A VAWT simulation using Ansys Fluent Sliding mesh technique
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- Опубликовано: 11 сен 2024
- A vertical axis wind turbine simulation using Ansys Fluent. CFD is a method that is used for approximate solutions (numerical solution) that are used for solving real problems in life which are simple or complicated in their mathematical models. CFD is just an approximate solution! Here is the reference of a simple illustration.
www.mediafire.c...
![[CFD] Large Eddy Simulation (LES): An Introduction](http://i.ytimg.com/vi/r5vP45_6fB4/mqdefault.jpg)
All the CFD links that I have..
www.mediafire.com/file/94154a13ce94uxc/CFD_links.txt
Check out your e-mail dear Jamal please..Thanks
You are the best. Just see the way you are taking time to respond to your fans. I've searched on RUclips but your video made it so easy to understand things. Thanks
Thank you very much dear Rejoice :) You're very much welcome!
i performed all the similar steps but when i check in run calculation before starting the solution it shows me "Review wall motion. Stationery wall motion relative to adjacent cell zone detected.(Boundary condition)."
The re is something not right with the geometry or the mesh...Try each step again. Thanks
For the wall function, you can read about the different types of it in ansys theory guide and the y+ conditions...This affect the solution greatly.
how to find Cp?
Everybody checks out the trailing edge after the mesh process to be sure that the mesh surrounds it and there is no overlap like the problem in the mesh of this video. You can try edge sizing for the airfoil.
at 18:57 there is a circle outside of these airfoils but from which you import this diagram there is no circle outsides of airfoils, again you had started the sketch2 with a rectangle at 19:01, but how can you get sketch1 and sketch2 at 21:01? may be that is why im facing problem at 22:15 to do line from edges. please help me out as soon as possible.
Hello dear Dipta, simply, once you import the rotating domain including the airfoils and the circle, create a surface by selecting the circle, boolean the surface of the circle from the rectangle, (if you have a full rectangle surface) In other words, we have to find a rectangular surface with a hollow circle. This hollow place will be for the surface you create for the rotating domain. After doing this, you create surfaces for all airfoils, then boolean each airfoil surface from the circular surface. you must find that the airfoils are hollowed. What I did is that I drew the rectangle with the circle that has the same diameter of the rotor's circle to only create a surface for the rectangle without including the place of the rotor. This is easier. Then I created the surface of the airfoils. You got sir? Danke !
@@haveanicetime I can't select the circle as you did at 22:13 during Lines from Edges step.
I made the circle after the airfoils.......and I made another circle plus the rectangle in another sketch. I followed exactly as you did. But when I am trying to select the circle, I can't. Hence I cant draw the surface in the next step, and eventually cant apply the Boolean
I cant import my 2D sketch from solidworks to ansys. If it opens it shows only 1 Airfoil
Hello dear Ankam, create a surface in SOLIDWORKS before exporting the file. I think this was the method that worked. Also search for exporting 2D files from SOLIDWORKS into ANSYS. Thanks
Hello sir, to compute the coefficient of moment for the turbine should we take moment center as geometric center of turbine or geometric center of the blade
Hello dear M, the moment center is the origin of the whole turbine. This means that Moment(torque)= Force* Turbine Radius. Danke!
sir, why you didn't use wall motion (rotational) airfoil in Boundary Condition? why you just use mesh motion in cell zone condition? thank you sir :)
Hello dear Hodik, we use mesh motion in cell zone (rotating domain) to tell fluent that this is the rotating mesh that has the 3 airfoils and all of them rotates with a specific rotating speed..This is the sliding mesh technique and following these settings make the airfoils rotate and let us study the unsteady behavior of the air around the rotating airfoils :)..There is another settings for the steady state analysis and you can read about them in ansys fluent user guide :) ...Thansk
Hello Sir, I am using ANSYS 21, I am trying to mesh 2D vertical axis wind turbine but "Mapped Face Meshing' option is not showing...kindly help..
I replied to your email. Thank you
hello. very good video. may i ask why the inner domain as well as outer domain is both add material rather than one being add frozen and one being add material
Hello dear Farhan, I think it worked because I did not imported the outer domain from a CAD file, insteadI dre it in the a new sketch in ANSYS. Anyway, the reference is the results and validation. Thank you
The prescribed speed of the rotating mesh in rad/sec should be positive or negative if its moving in clockwise direction ?
If you watch the video carefully you will find the sign related to the rotation direction.
the contours of velocity and pressure change as turbine rotates, so may i know at what angle are the contours of pressure and velocity showed in the video
Hello dear Korrati, they are after running the simulation for some timesteps. I do not have the solution files anymore because his tutorial was recorded more than 3 years ago. You can run yours and know exactly the time and the angles. Vielen Dank !
hello i am to intrested to do VAWT blades of aerofoil shape i do not understand the problem where it is. So, please help me
Hello dear Raju, tell me please the details of the problem. Thanks
Hello,
I am doing helicopter rotor blade in fluent.
I dont know where is the problem!
The blade doesn't rotate!!
Data input are not correct
Contact me on 12317@eng.asu.edu.eg
For the wall function, you can read about the different types of it in ansys theory guide and the y+ conditions...This affect the solution greatly.
Hello sir,
I have simulated the flow for a tidal vertical axis turbine, but the Cp values and torque is way off. Every boundary condition and solution setup is correct, even the reference values. Can you help me??
Hello dear M, you have to check all the steps again and the reference values can be changed until we get the predicted results because even if the reference values are correctly calculated, the 2D simulation does not simulate the flow correctly because of its unrealistic nature. Change the reference values until the values get better. Sometimes we have to increase them to equalize the 2D concept of the infinite cross section of the 2D. Danke!
@@haveanicetime thanks for the input sir, but this is happening for the 3D case too. We are not sure where it can go wrong. Any inputs for that sir.
Hello dear M, I am not sure actually, there is something not correct with the model or the mesh or the setup, make everything again from scratch to know the source of the issue. Danke!
@@haveanicetime we are trying to validate a paper, but not able to get the trends although we have given everything same to what is mentioned in the paper.
@@msaisantoshpavankumar9749 Watch my video about the 3D VAWT and turbine ventilator if you have not. Make everything again from scratch until we get something close. Danke!
hello dear sir, i am an undergrad student from Mechanical Engineering, attempting my thesis on Darrius VAWT. Firstly I want to thank you for this detailed tutorial the like of which is very rare in the internet. as a newbie in this field I am facing many confusions with my 2d CFD simulation for validation. it would be of tremendous help for me if you could provide me with your valuable feedback. could you be so kind to let me bother you with the brief details via mail?
Hello dear Sadman, you are welcome! yes send me some details by e-mail: mech.eng.ahmedmansour@gmail.com Danke!
thank you so much for your time and early response! this means a lot ❤️
i am sending them as soon as I can.
hello sir, thank you for the tutorial. I am working on a VAWT too. I was wondering that you have input the rotational value yourself. How do you make the turbine rotate on it's own due to the wind like in actual. The turbine should start slow and than reach a maximum rpm depending on the wind speed. Can you please guide me on this? Thank you!
Hello dear Muhammad, this simulation is for the turbines that work at fixed speeds. We ignore the starting up period. That's why we use sliding mesh. If you wanna let the turbine rotate due to the wind considering the starting up, the dynamic mesh 6 dof method is used. You have to watch my tutorial about this case in my playlist. Danke!
@@haveanicetime Thank you very much for the kind reply. Can you please share the link to that video with me? Also i am working on something similar....i am trying to find an optimum design. Now, as far as i know after solving the case you have to go to time history and calculate the rpm manually. I am stuck here....i get to this point just fine....but what i want to do is that i want cfd post to provide me the max rpm a turbine would run at, at a given wind speed. I want this because I want to parameterize the input and output and create a optimization process. If you can please guide me on this. This will a lot help to me.
Thank you!
To calculate the critical Re of an airfoil...you may use this Re=2.9Re^0.4...use the link to download the book.
www.mediafire.com/download/we2mxxmn35l5818/Aerodynamics_of_Wind_Turbines_2ed%2C_Martin_Hansen_%282008%29.pdf
www.mediafire.com/download/8pn8fnbklu2n6ko/Paper_on_transition.pdf
Check out this for more information.
www.mediafire.com/download/2jvj8kcn3zc8uii/VAWT_Model_CFD%282%29.pdf
www.mediafire.com/download/m8t73q9t39ttqrt/Thesis_on_suction%282%29.pdf
Can you display rpm in this simulation ?
Hello dear Handoyo, i am sorry, what exactly do you mean? Danke!
Can this simulation show (rpm) radians per minute of turbine rotation?
Hello dear Handoyo, we determine already the rpm or the rad/sec of the turbine in the mesh motion tab and it is fixed. Check out please some studies related to this kind of turbines to know more about it and how the researchers get benefits from the software to reach the conclusions. Danke!
How to find Cp?
Hello, the power coefficient= P_T/P_wind= M*omega/0.5*rho*S*V_inf^3 =(0.5*rho*S*V_inf^2*L*C_m*omega)/(0.5*rho*S*V_inf^3)= (C_m*L*omega)/V_inf=C_m*Lamda, Lamda is the tip speed ratio, so you simulate the c_m (make a monitor for the c_m of the whole turbine by selecting the 3 airfoils ) and multiply it by the Lamda..Okay? Thanks
@@haveanicetime Hi..And Thank you very much for replying...I would like to know what should be the reference values of area length and depth for simulating 2D VAWT
I am simulating a 2D in VAWT with multi element airfoil...to increase Cp...My turbine's diameter is 2 m while the size of rotating zone is 1.35D. I have generated a structured for both near airfoil and farfield region
I would like to know ur opinion on effectiveness of using multi element airfoil to reduce dynamic stall and increasing Cp
Hello dear Ali, you are welcome! You can watch my 2nd tutorial about turbines, it is about a 3D wind turbine and I showed some information about the reference values, it is just a trial and error approach until you get the good validation against the experimental results, the tutorial is in the playlist,
MultiElement Airfoils is a computer aided engineering (CAE) tool for calculating the aerodynamics of isolated or multiple airfoil shapes interacting in a flow field. Engineers and design professionals use it to rapidly and accurately compute aircraft, marine and automobile flow scenarios on an ordinary Windows based PC, notebook or tablet computer.
MultiElement Airfoils is a turn-key product that eliminates grid generation hassles and accurately computes lift, drag and moments for a group of airfoils and individual airfoils within the group. The software generates graphs of pressure, Mach number, temperature and total pressure using built-in post processing tools (it does not require additional third party software for pre or post processing).
MultiElement Airfoils is an excellent tool for optimizing cross-sectional shapes and getting the correct placement of aerodynamics components for aircraft, automobiles, boats, house hold products and other equipment. I know this from the website
www.hanleyinnovations.com/mefoil.html
So, you are doing a great job! Viel Erfolg! Ask me if you have any other questions!
Great video!! I am currently doing a transient fixed vertical axis wind turbine simulation top simulate the starting conditions of a VAWT however I am having a few issues wioth the results, would It be ok to ask you a few questions over email? also why have you changed the axis for the lift and drag monitors? and does it make a difference changing the inlet velocity to components and then setting the y velocity to 0 as opposed to setting the value for the velocity magnitude
Dear Rikesh, thank you for your kind comment...I changed the axis of the monitors according to Dr. Dalyo's video about flow around a 2D cylinder on youtube..I think he did this to tell fluent that we want the values of the lift coefficient to be monitored on y axis with the time on x axis and nothing more...So, I followed his method :)...You can senf me your questions on 12317@eng.asu.edu.eg and also I have uploaded a tutorial about a 3D VAWT and a turbo ventilator...you can watch it for more information..I have shown some references and some tips for calculating the performance coefficients...Thanks
Do you have a problem with contacting with me sir?
Have a nice time!
I apologise for my tardiness, I just need my next set of results to work with but they take around a day to simulate. I will contact you tomorrow if that is suitable because I have lectures all day tomorrow
Okay sir :) No problem at all...Take your time :)...Good luck and have useful lectures...
Hi bro, I have a doubt, how did you choose the angular velocity? How do i know that the turbine reaches that velocity .. I'm making my degree job about a hydrokinetic darrieus turbine and i do not understand why all simulation are carried out that way, could you explain me ? thank you, warm regards from colombia.
Hello dear Alejorol :), Basically, the rotating speed is omega (rad/sec) and it is the Velocity V (m/s)/ Rotor radius m...there are different kinds of wind turbines...one of them is fixed speed fixed pitch and this kind has a fixed omega regardless of the wind velocity magnitude...Omega is fixed all the time and the pitch of the blade is constant...Also there is a variable speed turbine which accommodate the wind velocity by changing its rotating speed omega..So, at wind speed = 6m/s, you have an omega and at another wind speed you have another omega etc.Also you may have a fixed speed variable pitch and variable speed variable pitch...So, according to you realistic design, you have to know if omega is constant or not...the tutorial shows the setup procedure and if you have a constant omega you have to carry out the simulations at many wind speeds at a constant omega, if you have a variable omega you have to calculate it at each wind speed following the basic rule and you can find this in the reference of Hansen....Check out please all the links that I put under the video, you will find the reference and some research papers and a thesis...Thanks and tell me if you have any other problem...:)
Have a nice time! thank you brother in this moment i am devolpe the DMS model on mathlab and validate it before on ansys, kind regards from colombia
Okay...Good luck :)
you might want to try QBlade too - it is open source and it based on streamtube models also
Hello, this is the other way of simulations, ruclips.net/video/vrhHs6QbyTU/видео.html
Sir your video is not playing.
Hello dear Inderjeet, just wait until it plays, sometimes the RUclips becomes heavy, I have used Internet Explorer and it is okay :)...
Hi,
Thank you for your video , I follow your video from the beginning till the end but it's seems i'm not getting the same results. precisely in the Fluent part where I'm getting an Error in Boundary conditions'' Review wall motion. Stationary wall motion relative to adjacent cell zone detected''.
Would you please help me resolve this issue or is it possible to share your ANSAY file to compare?
regards
Hello dear Mohamed, please, recheck again the steps, there is something not right, I am no longer have these files, but it is very simple, recheck again, if you miss any step you will face some errors, this is the sliding mesh technique, it is sensitive to the geometry handling and interfaces....Recheck again and tell me please...Danke!
Hello Again and Ramdan Karim,
Well, i checked again the steps as you mention, apparently, the meshing nodes number is the only difference between mine and yours but still getting the same error i mention before.
I'm about to present my simulation soon and i really need your help, do you think i can send you my file to be checked. what do you think?
if yes please send me your email.
regards
Hello dear Mohamed, okay, send it on mech.eng.ahmedmansour@gmail.com
Dear Ahmed,
Sent, please check out your email.
Regards
Mohamed
Received, Thanks.
Thanks for sharing the video.
I had a doubt, when I change the TSR, which means I am changing the velocity at inlet, while the angular velocity remaining same, I see that the Torque goes on increasing with the increase in the TSR (with smaller values of wind velocity). In fact for a particular airfoil the torque should increase upto a certain point for the corresponding value of TSR and then it should decrease. How do I tackle that. Please let me know.
Thanks in advance.
Dear Parikshit, not at all :)....To plot the tip speed with the power coefficient or the torque, you should carry out many simulations with different inlet wind speed at the same rotating speed of the turbine. Then you can calculate the average torque value for each simulation because the simulation is unsteady. I think that you see the torque increases because it is not the curve of the tip speed ratio with the torque. It increases with time of this particular simulation only at this period of time at this certain time step and mesh size. So, you should carry out simulations from tip speed equal 2 or 1 as an initial point and calculate the average torque or the torque at a certain time, and carry out simulations up to tip speed equal to 20 ...every simulation has its torque and tip speed...so you can plot these values using a spread sheet like Excel to check out the results.
Thanks a lot for the reply. I can email you my workbench file if you allow. Can you please look into it and reply your comments on it through email. I am in an urgent need to solve this problem. Please help me out.
@@parikshitghogare6212 hey prakashit i am going throught the same problem..can u let me know how did u sort it out?
@@haveanicetime what i have been doing is keeping the inlet velocity const and changing the angular rotation for each simulation depending upon that required for the TSR .. am i doing it right or i should do it the other way ..like changing vel and keeping the angular vel of blade constant ?
What about the reference values???
Watch my video about 3D VAWT and turbine ventilator because I talked about that in that video. Thanks
How can I construct 4 airfoil blade sliding mesh using designmodeler or autocad? Thanks
Hello dear Ladokun, you can make a circular pattern but the number is 4 not 3, then you will have 4 airfoils in Autocad...Check out this link please...
ruclips.net/user/results?search_query=circular+pattern+autocad
For the wall function, you can read about the different types of it in ansys theory guide and the y+ conditions...This affect the solution greatly.
sir i cant open your mediafire files.will u me please?
Hello dear Tajbhi, what exactly do you want? Danke!
actually i cant go to the link. I want the geometry file at first, sir.
Hello dear Tajbhi, the link does not have the geometry. I do not send the geometry because it is easy to be done. The link has a txt file that has some links related to some websites and CFD references.
Danke!
Hi, I am working on my graduate thesis about air flow in Savoinus turbine (2D) and your videos including links you put here, are probably the most useful materials I found on the internet regarding my issues. So, thank you very much kind sir :). For problem I am working on I drew 3D and 2D model. 3D model is meshed by sweep method (one element per high) and I am not sure would changing reference values help or is cross section area defined by 3D geometry? This is the first time I am working with sliding meh and I have oo soo many doubts. Could you be so kind and let me write you an email with few questions and some prtsc? :) Thank you in advance
Hello dear Ana :), you're welcome :), you can contact with me on 12317@eng.asu.edu.eg and send me the details of your models, also watch my tutorial about the 3D wind turbines for some information about the performance curves...Thanks
Thank you for your quick response :). I'll send you an email within 2 hours, thanks again :)
Okay :)
Hello sir, thank you very much for this tutorial. I have a request. I have been stuck with my simulation for a long time and am failing to draw power coefficient vs TSR graph. I have been studying from different sources and searching for a way for too long and now my deadline is very near. Any input from you will be greatly appreciated. Thank you.
Hello dear SK, I am sorry I was sick. Watch my video about the 3D turbine ventilator and VAWT because I showed how to generate such curves. Danke!
for rotating domain, how did you find the angular velocity for mesh motion ??
Hello dear Sumit, from the basics of wind turbines, V=omega*Turbine_radius Danke!
@@haveanicetime As per my understanding , due to the pressure angle every time velocity will change as air will only flow in x direction but the angle it is making with the airfoil will make have impact on velocity.
Please correct me if I'm wrong.
@@sumitpatil6346 Simply there are different types of wind turbines, this type shown in the video is the fixed rotation speed fixed pitch. You can read about the other types in any wind turbine reference covers the aerodynamic basics. Danke!
@@haveanicetime Ok, Actually I'm working on Savonius Turbine. In that velocity is sinusoidal in nature. I tried dynamic mesh method, but the simulation is not working so I thought I should give try to sliding mesh method.
Can you suggest some material where I can clear concepts related to dynamic and sliding mesh method
Thank you!
@Sumit Patil Well, you have to get research articles related to your point of research because you will find the previous numerical models and their physics. Before using the software, you must do a literature review. And you must get a wind turbine reference that has the different types of turbines. If the wind velocity is not constant, the variable wind velocity equation is used and I showed this in one of my tutorials, sliding mesh simulates the fixed speed of rotation. It mainly depends upon the research articles and the type of turbine you have Danke!
I created a 2d sketch of 3 naca0018 airfoils similar to yours in solid works ,but while importing geometry in ansys only one airfoil is displayed that too at the origin and not on the circumference I drew.
I tried step & iges format to import
Hello dear Pinak, try parasolid_xt. Danke!
@@haveanicetime I tried saving it in parasolid x_t format but error pops up saying format doesn't support this type of geometry
I found that for solid works I had to create suface plane ..after doing this I could import using all stp , parasolid and iges formats and it opens in ansys with planar surface and proper geometry.
Anyways, thankyou sir!
You are very much welcome dear Pinak, okay, that's pretty good! Danke!
Great video! Is it possible you will make a tutorial on NREL phase VI wind turbine??
Thank you very much dear Estay :), do you mean optimizing the blade like the attached link? Thanks
metacomptech.com/images/VDWebsite/Content/AllValidationCases/NREL%20Phase%20VI%20Wind%20Turbine%20Rotor.htm
thank you for your reply, I mean run fluent simulation on a wind turbine rotor.
Hello dear Estay, could you please send me some details about your point on mech.eng.ahmedmansour@gmail.com ? Vielen Dank!
ruclips.net/video/HBQ-liI4Q_I/видео.html
ruclips.net/video/fxFZyiWt_Xc/видео.html
Yes, okay you wanna a simulation about a horizontal axis wind turbine, I will prepare it to be simulated in FLUENT, okay? Thanks
Ok i will contact you by mail i have my batchor project making a gorlov turbien inside a pipe so i wanna to make sliding mesh for this situation i make one but in the animation part I don't know how to continue ..
+Amr Hasan Keep goin'
+Have a nice time! You should define the interfaces carefully like what I have done.
To calculate the critical Re of an airfoil...you may use this Re=2.9Re^0.4...use the link to download the book.
www.mediafire.com/download/we2mxxmn35l5818/Aerodynamics_of_Wind_Turbines_2ed%2C_Martin_Hansen_%282008%29.pdf
Check out this for more information.
www.mediafire.com/download/2jvj8kcn3zc8uii/VAWT_Model_CFD%282%29.pdf
www.mediafire.com/download/m8t73q9t39ttqrt/Thesis_on_suction%282%29.pdf
www.mediafire.com/download/8pn8fnbklu2n6ko/Paper_on_transition.pdf
I have imported the stp file to ansys Why doesn't the airfoil appear?
Hello dear Handoyo, try to import it as an x_t file but before that be sure that you made Line body "Yes" before hitting Generate. Danke!
Thank you so much
Thats helpfull
You're welcome dear Handoyo. Danke!
Your explanation is very nice I have a question about how we can plot the momentum against the azimuth angle Or TSR against power cofficient
Hello, you're welcome! Simply get the paper that shows those graphs, then you will change the TSR and run different simulations, then get the torque coef. from the simulation and calculate the power coef. using the formula. That's it.
Thank you, change Tsr means change omega inside simulation. Is it correct?
@@najmnajib6864 Yes, the tip speed is the omega x radius of the turbine. Changing omega changes it..Check out the formulas for the references...Thanks
Hello sir your videos are so helpful.
Thank you very much dear Inderjeet :)
sir,i m trying simulation of horizontal wind turbine,but i m getting some problems in setup,could u give me some guidance.
Hello dear Ananya, contact with me on 12317@eng.asu.edu.eg to discuss the details :)..Thanks
Do you have a problem in contacting with me? It is better to send me the design to check it out....Thanks
thank you sir
Not at all and waiting your e-mail :)..Thanks
I am running a static case of the same thing and I am getting the same contours of velocity as shown as 1:31:34. The interface has been defined but it still acts like a wall. The streamlines show that the air get deflected upward instead of passing through the interface. Can you identify my problem?
+farhan javed222 Dear Farahan, I don't understand what do you mean by static...Do you mean steady? ...To be sure that you define the interfaces well, you should open fluent and check out the interfaces tap, is it active or not, if yes, you should open it and you must find interface 1 and interface 2, your problem may be due to defining the interface wrongly...you should suppress bodies like what I have done to cancel all other bodies except the current body ..If you don't make this, you will find many planes appear at the down left side and you have to select the right plane but this method is not recommended....So, follow what I have done carefully to make sure that the interfaces are activated well...You may find the interface tap is activated but you may find one interface is the only activated..this is due to the multi planes issues...Suppress bodies may help you....try it again please step by step.
I actually meant to say steady state. I have properly defined the interfaces and I can see them in the mesh interface tab as well as the bc tab. When I run a steady case with no frame motion the air flows through the interfaces. But as soon as I enable the frame motion, the air stops flowing through the interface. What do you think is the problem over here?thanks for your earlier response.
+farhan javed222 What is the model you use and did you set the fixed and rotating domains conditions? Sliding mesh is for setting a rotating speed in rpm for the rotating domain by enabling the mesh motion tap not the frame motion because the frame motion is another method which is different from the frame motion , the fixed domain is fixed mesh....you can set the model to be laminar and steady flow...this gives a solution....If you changes the model to any turbulent model like k-e , you should make it transient....In any case...you should set a rotating speed to make the rotating domain slide on the fixed domain...This is the main conditions of using sliding mesh, you may set the rotating speed equal zero but I thing you should enable the mesh motion in any case or you will have many errors in the solution. :)...This is my guesses..Keep going :) and try to read the theory book of ansys fluent to know the differences between sliding mesh, moving reference frame and multiple reference frame.
I have used the k epsilon model...I have set the rotating domain using the frame motion and the fixed domain is stationary. I have given the rotating domain a speed of 16 radian/sec.
I have infact used my setting before an executed the CFD properly. However, when I am trying to repeat the CFD with a different blade chord I am unable to get it to run properly.
Hello once again! Greetings! I tried this problem and it works for me. I have one question though. I have understood the time steps concept and transient solution. Just out of curiosity I decided to solve the same problem with steady solver, frame motion instead of mesh motion. In both cases I used "write" option in monitors for getting cm values for each time step and iteration respectively. For similarity, I used 36 time steps with 200 iterations each (as per my input one time step meant 10 degrees azimuth angle change) so total 7200 iterations and for steady solution I took 7200 iterations. Now interestingly, the moment at the end of last timestep and last iteration respectively for each case is EXACTLY SAME. The plot of cm wrt timestep for transient sliding mesh method is just like you have explained (fluctuates from positive to negative and average is positive). But the plot I get for cm wrt iteration, for steady frame motion method makes absolutely no sense! However as I pointed out, the final values of moment for both cases is EXACTLY SAME (since iterations are same, 7200)
So my question is:
As we calculate and set delta t such that each time step represents fixed change in azimuth angle (10 degree per time step in my case), the cm vs time step plot makes sense as each time step means certain azimuth angle increment. Similarly, what does each iteration in steady solver mean? How can we make sense out of cm vs iteration plot?
I would have considered the steady solution as garbage but the as the final moment values are exactly same (upto 4 th decimal!) I got curious and thought maybe even steady solution has some meaning.
Thank you for your kind help. Sorry for the long comment, but I just wanted to make it clear why and what I'm doing. Cheers!
Hello dear Japun :) :)..Thanks for your good question :)...Basically, from my experience, the steady state solution is to initialize the unsteady state solution especially for the problems that have unsteady flow like wind turbines and the other turbomachinery ....So, when we solve a flow inside a pump, we start a steady state solution using frozen rotor or stage (mixing plane) methods just to initialize the transient solution...The same for wind turbines, you cane use the steady state methods to initialize the unsteady solution but the difference between the steady state solution and the transient is as follows...The steady state is used to get the converged accurate initial solution for the unsteady problem..this means that you have a vawt and it is transient..you can start the solution as steady to reach a good convergence for the values..every iteration, you will find the cm values changes with the ITERATIONS and after many iterations, it has to be fixed (no changes) and this means that the solution for the cm value in this steady case is this number ..the same for the other values..they change with the iterations until they become fixed and no changes and here you know that this is the final right value for this steady solution and the solver will take it to START the transient solution and then you will find that this value changes with time because the flow is unsteady :) and it has to fluctuate :)..So, we take the AVERAGE of the TRANSIENT solution and the FINAL value of the STEADY solution....So, if you solve the problem as steady, you have to reach 10^-4 or lower 10^-5, -6,-9 in the convergence and you have to see the values do not change anymore with the iterations..here you have to stop the solution and take the last value as the final fixed solution to start the transient simulation with it and see it fluctuates....attached a link for some CFD references...check them out and read the moving reference frame in ansys fluent theory guide and the sliding mesh technique..That's why we use sliding mesh for the majority of the cases in fluent, to start the solution steady for some iterations and the solver automatically complete the solution as transient and we know this when we see the RESIDUALS fluctuates...Thanks
Tell me if you still have a confusion...
www.mediafire.com/file/94154a13ce94uxc/CFD_links.txt
Thank you for your reply. My concept about steady and transient wasn't clear before. Now I know difference better than before. And the links are helpful too! :)
This makes me very happy :)..Thanks dear Japun and I am trying to write a code for a variable rotating speed wind turbine :)..Thanks
Hello, this is the other way of simulations, ruclips.net/video/vrhHs6QbyTU/видео.html
I am supposed to do CFD analysis for a VAWT hybrid between savonius and darrieus! I want to use different overlap ratios for savonius and draw velocity and pressure contours to see and optimise power coefficient for the hybrid! do you think if I follow this I can achieve the results?
+Himanshu Dikka Dear Himanshu Dikka, do you mean that you will make a one simulation for the 2 turbines or you will make 2 simulations , one for the 1st turbine and the other for the 2nd turbine and compare between them?
+Have a nice time! I mean one simulation for both (probably darrieus on top of savonius)
If you will draw the 2D airfoils and have a rotor ans a stator domains, you can do it....you can contact with me on 12317@eng.asu.edu.eg, you can send a snapshot of the drawings to tell you my opinion :)
+Have a nice time! Yes! I am not sure about how to have a rotor and stator domain created. I will email you! You want the solidworks drawing? I m not sure how to do a 2d simulation for a darrieus rotor on top of savonius. Thanks!!
Okay :)
Hello sir,
Mesh interfaces option is disabled in my ansys fluent can you please help me in this issue.
Hello dear Korrayi, the interfaces were not correctly defined in the meshing step. Check it out again. Danke!
@@haveanicetime
I have defined the interfaces as you mentioned in the video. But in set up mesh interfaces option was disabled
@@haveanicetime
Thanks sir, it helped me to solve the problem
@@haveanicetime
Sir,
What is rotation axis origin in cell zone conditions.
If the turbine is drawn in xy plane, the axis is z. I am sorry I do not receive the notifications because they are modifying the creator studio. I am sorry. I have to manually check out all comments and this is not easy. Danke!
Thank You Very much for your nice tutorial.
May you please explain why you used rotational velocity to rotate the turbine? While it should rotate with wind speed.
You're welcome dear Mostafa :)..Simply, we assume that the wind speed is constant because we carry out the experiments inside a wind tunnel at a fixed fan speed and the large scale experiments are carried out in a location where the average wind speed is also fixed. So, we use the law V=omega*R..where omega is the rotational speed in r/s and R is the rotor radius in m and then we calculate omega as a fixed rotational speed for the fixed speed wind turbines...Another option is the variable speed wind turbine which changes the rotational speed based on the variable wind speed...In this case, we have to write a c++ code to define the variable omega but I will try to record a tutorial for this..Check out please the links here and download all the references that I have uploaded....Thanks
Thank you for your response
So what was the need to give velocity in the inlet? I think in this case there is no need to inlet and we should have both outlets.
(Excuse me for beginner questions)
I am trying to simulating and validating the article below:
www.sciencedirect.com/science/article/pii/S0306261912009555
I did a simulation for it with help of your tutorial, and you can see it in the link below, however, I know that I made mistake :)
ruclips.net/video/_hKYRx6j2E0/видео.html
I think this case is the option that you said it need c++ code.
This is a good question :), the inlet velocity represents the wind speed that enters the domain. This is very important to simulate the moving air through the fixed domain and the rotating speed of the rotor is to simulate the rotating turbine (sliding mesh ) to show the different positions of the rotor during the simulation of the unsteady flow behavior and we can study the separation of the flow at the blade's surface and the laminar and turbulent boundary layers, and the performance...
Thank you very much for the video, I downloaded it and you can delete it now....I have checked out the paper..I think that the idea is to use the guide vanes and test the turbine performance to compare it without guide vanes...Simply, adding the guide vanes enhanced the self start speed ..this is because without the guide vanes, the turbine could not start rotating if the wind speed is lower than 7.35 m/s but adding the guide vanes made the turbine self start rotating at only 4 m/s and this is the enhancement because you do not have to put the turbine i a place that has a wind speed higher than 4 m/s, also the rotating speed increases and this increases the torque and the power :) ...I think all the experiments and simulations are at a fixed wind speed and rpm..The idea is to compare between two ideas :)..I hope this helps you...Thanks
if it's water turbine , what should i change ?? and your mail please
+Amr Hasan You will change the flow type, set it water liquid not air from the fluent data base, calculate Re number to know if the condition is laminar or turbulent, but due to Von Karman effects and the nature of the wakes, we set the simulation as transient"Unsteady"...According to Re number, assume the turbulent intensity or find out empirical formulas related to the water wind turbines, check the domain dimensions to be sure that the turbulence is damped before the trailing edge of the airfoil. 12317@eng.asu.edu.eg
For the wall function, you can read about the different types of it in ansys theory guide and the y+ conditions...This affect the solution greatly.
to make a circular pattern what function should I use in autocad?
+Himanshu Dikka
ruclips.net/user/results?search_query=circular+pattern+autocad
+Have a nice time! thanks sir! I had seen it before but I had some technical problem. Also after we draw the wing airfoil using the coordinates in autocad, is it possible to change the length of it? mine is stuck to 1 unit- which is in meters- so it is 1 m in length
Yes, make scale like what I did in the tutorial using scale.
www.mediafire.com/download/we2mxxmn35l5818/Aerodynamics_of_Wind_Turbines_2ed%2C_Martin_Hansen_%282008%29.pdf
www.mediafire.com/download/8pn8fnbklu2n6ko/Paper_on_transition.pdf
Sir please upload video regarding combined savonius and darrieus VAWT.
Hello dear Inderjeet, I uploaded a video about 3D simulations for a turbine ventilator and a VAWT, check it out please in my playlist and you can contact with me on mech.eng.ahmedmansour@gmail.com if you have any questions or any problems related to your project, we can work on it together :) Thanks
Do we need to put any equations? and which equations?
+Himanshu Dikka If your simulation is just like this, no need for any additional effort, but there is a source input if you want to add any source to Navier Stokes equations. If your study is like what I did, no need for any additional action.
www.mediafire.com/download/we2mxxmn35l5818/Aerodynamics_of_Wind_Turbines_2ed%2C_Martin_Hansen_%282008%29.pdf
www.mediafire.com/download/8pn8fnbklu2n6ko/Paper_on_transition.pdf
www.mediafire.com/download/2jvj8kcn3zc8uii/VAWT_Model_CFD%282%29.pdf
The skewness is recommended to be lower than .85 and the mesh should be structure around the airfoil to capture the boundary layer...you can get CFD references and Schlichting for more information.
Everybody checks out the trailing edge after the mesh process to be sure that the mesh surrounds it and there is no overlap like the problem in the mesh of this video. You can try edge sizing for the airfoil.
Thank You Very much, it really helps me, could you please produce a Video illustrating how to get cm-TSR curve? this is really challenging for me since I just started working on my thesis
You are welcome :) ...could you please watch my tutorial about the 3D VAWT on playlist? The tutorial contains some information about the performance curves ...watch it and ask me if you still have questions :) ..Thanks
alright, thanks in advance.
You are welcome :) Thanks
For more information about the performance coefficients. Kindly check out my tutorial about a 3D VAWT and a turbo ventilator..Thanks
ruclips.net/video/1pA_yk2a4po/видео.html
Hello sir
U r video helping me a lot.
Does same process setting works in transient condition for NACA 0018
Hello dear Rohith :) You are welcome, you can use any design of any airfoil, just you have to know the coordinates and the angle of attack and do the same procedure, if you have more questions, you are welcome :)...Danke!
Does same process setting works in transient condition for NACA 0018??
Thank you, I ll get you back if stuck somewhere
Okay and you are welcome :)
Hello Sir
I'm unable to do the Boolean at 22:51
do i need do draw the outer circle in inventor only before going to ANSYS?
sir, how did you get the speed (rad/s) at 1:50
Hello dear Zuhairi, what speed at 1:50? Danke!
@@haveanicetime sorry, I mean 1:50:50
@@zuhairisapudin5429 Okay, depending on the wind speed, V_tangential (or V_wind) = omega*turbine radius. So, get the tangential velocity of the wind or use the wind speed for approximation (Check the research articles) and calculate the omega in rad/sec. Danke!
Tq. I've one more question. How to know whether the solution already converge or not?
the way you explain the meshing part so confusing. I don't understand at all
thank you very much
You are WELCOME dear Jnan, I am so glad to help you :)....Thanks
Hello, I have watched your video and found it very useful in my research. My research is about a transient flow in a cross-sectional cylinder. Can I contact you by email?
Thank you dear Weiyin :)....my mail is 12317@eng.asu.edu.eg ....I have a playlist includes a tutorial about flow over a cylinder.
www.mediafire.com/download/we2mxxmn35l5818/Aerodynamics_of_Wind_Turbines_2ed%2C_Martin_Hansen_%282008%29.pdf
www.mediafire.com/download/8pn8fnbklu2n6ko/Paper_on_transition.pdf
www.mediafire.com/download/2jvj8kcn3zc8uii/VAWT_Model_CFD%282%29.pdf
The skewness is recommended to be lower than .85 and the mesh should be structure around the airfoil to capture the boundary layer...you can get CFD references and Schlichting for more information
Everybody checks out the trailing edge after the mesh process to be sure that the mesh surrounds it and there is no overlap like the problem in the mesh of this video. You can try edge sizing for the airfoil.
Salam Brother ..
I am looking to Model one component of the Turbine which is Tower and study the deflections plus rotation by studying stiffness, overturning moment, limit on natural frequency and model them on Ansys. If I can have your email address I'll write you in more detail what I am looking. Just point me in the right direction please.
Hello dear Shahzaib :) the e-mail is mech.eng.ahmedmansour@gmail.com
Waiting your e-mail sir...Thanks
unfortunately I've a prob with import geometry to Ansys
I hope You Can Help Me
Hello dear Abdelmoneim...what is the extension of the geometry file and what is the cad software that you used for the design process? Thanks
Thanks for replying , SW 2016
Okay, SW is not compatible with ansys in 2D cases (step files)..Try ACIS and if does not work, open the step file in ant other cad software you have or open the acis file by autocad and reexport it with the same extension and import it into ansys..if you still have a problem , send me the files and I am gonna convert them using Autodesk inventor because SW works only for 3D work...mech.eng.ahmedmansour@hotmail.com.Thanks
I've sent a message to Your mail
12317@eng.asu.edu.eg
My mail is abdlmoneimnasr@gmail.com
Send me the files please...
Good work . thanks
Thanks.
wow great work.
Thank you :)
www.mediafire.com/download/we2mxxmn35l5818/Aerodynamics_of_Wind_Turbines_2ed%2C_Martin_Hansen_%282008%29.pdf
www.mediafire.com/download/m8t73q9t39ttqrt/Thesis_on_suction%282%29.pdf
You did an excellent job by uploading this video..... Thanks for the video... Can you suggest me how to plot Cp (power coefficient ) Vs TSR Graph
+Bharath Ningaraj Not at all dear Bharath :)....You are welcome...You can calculate the tip speed ratio at every rotational speed and wind speed, you will get many points, to calculate the power coefficient at certain wind speed and rotating speed, you can calculate the moment of the turbine by clicking on Reports under plots and select moments, I think you should set the moment center to 0,0 , click print or write, you will find the total value of the moment in N.m at a certain time step, you can take the moment value after one revolution or you can take many values during one revolution....you will find that the moment value changes with time...you can read more about this on google to get the accurate moment of the turbine, you can calculate the time of one revolution and the number of revolutions per minute to set the time step, you can make it 0.0001 as an initial guess...you can monitor the Cm coefficient by clicking on monitor, moment and choose every airfoil or the three airfoils, I am not sure of the accuracy of the values...then you can write them to a file and take the average of each airfoil and add them together and substitute in the formula that attached in the next links...then you can calculate the power coefficient for this simulation...repeat the simulations by duplicate and change the wind speed and the rotating speed if the turbine can accommodate the wind velocity...recalculate what I have mentioned and you will have many points of TSR and Power coefficient.
www.researchgate.net/post/How_do_you_calculate_the_average_torque_using_CFD_in_Fluent
www.researchgate.net/post/How_can_I_calculate_the_Performance_Coefficient_Cp_from_Ansys_Fluent
www.cfd-online.com/Forums/fluent/39780-how-does-fluent-calculate-moments-dyanmic-static.html
www.google.com.eg/?gfe_rd=cr&ei=akgcV9qgNc-c-waRsL3gDA&gws_rd=ssl#q=forces+in+fluent+
www.cfd-online.com/Forums/fluent/98314-calculating-coefficient-drag-ansys-fluent.html
www.cfd-online.com/Forums/openfoam/91762-wind-driven-rotation.html#post322023
www.cfd-online.com/Forums/fluent/80208-torque-calculation-2d-vawt-wind-turbine.html
www.cfd-online.com/Forums/fluent/116999-wind-turbine-vawt-negative-moment-fluent.html
+Have a nice time! Thanks bro...
You're welcome buddy :).
www.mediafire.com/download/we2mxxmn35l5818/Aerodynamics_of_Wind_Turbines_2ed%2C_Martin_Hansen_%282008%29.pdf
www.mediafire.com/download/8pn8fnbklu2n6ko/Paper_on_transition.pdf
how get Cl vs time ?
+praditya sari In monitors select create-lift- and check the "write" option is marked; after the simulation ends you should find a .txt in fff/dp0/fluent named cl-history where you get the data
+praditya sari Do what dear jakfenix have told you and select the required airfoil.....Watch this video... Dr. Dalyo showed the method.
ruclips.net/video/DXWO-X16UIo/видео.html
What is Moment center and moment axis?
praditya sari Dear Praditya, check out these links
www.sharcnet.ca/Software/Ansys/16.2.3/en-us/help/flu_ug/flu_ug_sec_report_force_generate.html
www.cfd-online.com/Forums/fluent/47476-moment-report-fluent.html
www.google.com.eg/?gfe_rd=cr&ei=00pIV9WbEcus8wePwaGYDw#q=moment+axis+and+center+ansys
If you still don't understand, ask again :)
www.mediafire.com/download/we2mxxmn35l5818/Aerodynamics_of_Wind_Turbines_2ed%2C_Martin_Hansen_%282008%29.pdf
Watch my video about human development:
ruclips.net/video/_CgvG3OYUx0/видео.html
Ok sir, please send me your email. I need your help for my hybrid VAWT project work.
Hello dear Inderjeet, did you get what you wanted? I am sorry the notification system was not working while you were contacting me. Danke!
My boundary layer control simulation on a vawt using fluent...
ruclips.net/video/-_rrTzhOT5c/видео.html
Look at www.vertogen.co.uk
Vielen Dank!
Check out your e-mail please....Thanks