@@HoaiThanh-wm6ze In this case, his model is set up with y axis being vertically up. So NORMAL_Y is a scalar value, it's the component of the normal of each element in the vertically up direction. Pressure times that component is the force on that cell. Add up all the forces on all the cells to get the total.
I a not getting the same options as you when extracting block. I only get one option so i cant extract my geometry. I'm trying to do the flow over golfball vs a smooth ball. I used symmetry on my study. Don't Know if that might affect anything
When i go to block indices just appears a block called internal mesh, how a can create more blocks? I made mi simulation using a .obj in openfoam, i edited mi model in 3ds max
hi.. could you do a tut on the workflow i should take starting with a fresh model from a 3d suite like Blender all the way to visualizing aerodynamic airflow? thanks in advance
4 года назад+3
Nice video. Is there any way to incorporate the viscous drag?
Thanks for this nice video ! However I encounter a problem, my object (plane in the video) is not present as a block when I want to extractBlock, what do I need to do in my geometry to make it appear here ?
Hi, I tried this on one of my projects and the integrated values are showing the drag values without considering the viscous effect. Is it possible to get those values too, the software I did the simulations showed both the drag due to the pressure force and the drag due to the viscous effects. How do I get it on Paraview?
It's a late answer and you surely have figured it out by now, but for reference you need to have or compute the wall shear stress then include them in the calculation of the forces
Really nice video about the possibilities in ParaView ! It might also be interesting to know, how to create the 3D model. My approach would be to create a parametric model with Salome Meca Software by using the Python interface and get it meshed with hexa elements.
Hi, you said you have an air flow that's straight along the z-axis I believe. I'm trying to calculate drag and lift of a rudder, so naturally, I will do that in various angles of water flow. How do I do that? My Water flows in negative z-axis direction at 0 degrees. At 20 degrees it flows cos(20deg) in neg z-axis and sin(20deg) in neg x-axis. Do I just use those same factors in the lift calculation? So should it look like this: lift = pressure*(cos(20deg)*Normals_X+sin(20deg)*Normals_Z)
One simple thing one could do is to maintain the flow speed aligned with the simulation main reference frame and turn the geometry accordingly around the right axis. Otherwise you con project your velocity component inside paraview using the calculator filter.
I thought about turning the geometry, but I don't like that solution. I don't quite understand what you mean by projecting the velocity component. Projecting it where?
If your inlet velocity is slightly inclined with respect to the system of reference you can define a new system of reference that is aligned with the velocity, and then calculate the velocity components with respect to it, projecting them onto it. This means you have to compute the proper coordinate transformation via the cosine matrix and project the velocity vector. But you have to pay attention also to how surface normals are defined in such a case, since they are vector too, you should take it into account in the new system of reference. So probably turning the CAD can be the most straightforward way.
But can't I just calculate it as if I didn't have an inflow angle and add both, which should give me the resulting force vector? And then I can just take out the drag and lift components depending on my own frame of reference.
It can be a solution, it should work. You can calculate lift & drag for a 0 angle geometry and inflow, then rotate both the geometry and the flow inclination and use your approach to verify if it works.
Hi, Thanks for this tutorial. In my case I am not able to select a specific boundary surface as you did: The data hierarchy is set on Multi-block dataset. I can just select Fluid domain and a general Boundary. Do you know how I can solve this issue? All the best
I know this is old, but the solution is selecting openfoam reader from just above where the extract block filter appears in the tree in the top left and making sure the cut or wall that represents the aircraft is selected then hitting apply
Hi! Thanks for the video. I would like to make you a question. For the incomprensible case, the pressure is usually not in [Pa] but it is divided by the fluid density (so the unit is m^2/s^2). On that case should we multiply the pressure for the density in order to have the proper pressure? (and the proper forces). Second question. I am calculating the forces exchanged between a boat hull and the water (so density=1000 kg/m^3). Should I use the same formula multiplied by the water density or should I use the same formula? Thanks in advance for the answer!
I think I agree with you, but I am not sure. To get the total lift force the pressure load on the mesh face should be multiplied with the mesh face area.
@@lucderuiter8904 To be more precise, if you change angle of attack with velocity vectors this procedure will give Normal and Axial force. On the other hand, if you change angle of attack by body rotation it wil give Lift and drag force.
May I ask how i could extract the spanwise lift distribution before integrating, in order to adapt the wingplanform and obtain a bell shaped lift distribution in openfoam?
Sorry for the late reply. Anyway, the procedure in paraview is exactly the same. The only thing you have to change in your CFD simulation is the geometry configuration!
hi.. could you do a tut on the workflow i should take starting with a fresh model from a 3d suite like Blender all the w ay to visualizing aerodynamic airflow? thanks in advance
![[ Paraview Tutorial 5 ] Vector Visualization and Streamlines](http://i.ytimg.com/vi/1jml3j3BmUg/mqdefault.jpg)
This is exactly what i'm finding sir! Thank you so much. Hope that you can do more video like this for newbie like us to follow.
There are much more on our website: conself.com/blog/category/post-processing/
I am newer working with CFD. you can explain for me why lift = pressure * scalars y. I mean I can understand what is the scalars y. thank you .
@@HoaiThanh-wm6ze In this case, his model is set up with y axis being vertically up. So NORMAL_Y is a scalar value, it's the component of the normal of each element in the vertically up direction. Pressure times that component is the force on that cell. Add up all the forces on all the cells to get the total.
Around all info that I found in youtube. This is kind of elegant, clear math and consistency way to do it!, great for sharing.
I a not getting the same options as you when extracting block. I only get one option so i cant extract my geometry. I'm trying to do the flow over golfball vs a smooth ball. I used symmetry on my study. Don't Know if that might affect anything
It's been a while. Could you please tell me is there any chance to count Drag Coeficient from those data and how it is possible to do?
When i go to block indices just appears a block called internal mesh, how a can create more blocks? I made mi simulation using a .obj in openfoam, i edited mi model in 3ds max
hi.. could you do a tut on the workflow i should take starting with a fresh model from a 3d suite like Blender all the way to visualizing aerodynamic airflow? thanks in advance
Nice video. Is there any way to incorporate the viscous drag?
Thanks for this nice video ! However I encounter a problem, my object (plane in the video) is not present as a block when I want to extractBlock, what do I need to do in my geometry to make it appear here ?
I hope I'm not late. Yo have tu clivk in your .foam and then scroll down until you see your mesh regions. the you have to enable your surface.
Hi, I tried this on one of my projects and the integrated values are showing the drag values without considering the viscous effect. Is it possible to get those values too, the software I did the simulations showed both the drag due to the pressure force and the drag due to the viscous effects. How do I get it on Paraview?
It's a late answer and you surely have figured it out by now, but for reference you need to have or compute the wall shear stress then include them in the calculation of the forces
I can’t Select the cell data option, the program shows a error. Whe I select the point data, it’s ok, help
Hello thanks for the video,
Could you also explain how to find the centre of pressure location?
How to get lift coefficient
Really nice video about the possibilities in ParaView ! It might also be interesting to know, how to create the 3D model. My approach would be to create a parametric model with Salome Meca Software by using the Python interface and get it meshed with hexa elements.
i extract a hull of a ship and follow thw proces but i get a negative drag why is that?
Hai sir/madam i am also getting the same error. If you know how to correct the mistake please explain. Advanse Thanks.
Is it possible to take vorticity vectors over a wing Surface in paraview ?
how to get the pressure contour?
Excellent presentation - thanks
Hi, you said you have an air flow that's straight along the z-axis I believe. I'm trying to calculate drag and lift of a rudder, so naturally, I will do that in various angles of water flow. How do I do that?
My Water flows in negative z-axis direction at 0 degrees. At 20 degrees it flows cos(20deg) in neg z-axis and sin(20deg) in neg x-axis.
Do I just use those same factors in the lift calculation?
So should it look like this: lift = pressure*(cos(20deg)*Normals_X+sin(20deg)*Normals_Z)
One simple thing one could do is to maintain the flow speed aligned with the simulation main reference frame and turn the geometry accordingly around the right axis. Otherwise you con project your velocity component inside paraview using the calculator filter.
I thought about turning the geometry, but I don't like that solution. I don't quite understand what you mean by projecting the velocity component. Projecting it where?
If your inlet velocity is slightly inclined with respect to the system of reference you can define a new system of reference that is aligned with the velocity, and then calculate the velocity components with respect to it, projecting them onto it. This means you have to compute the proper coordinate transformation via the cosine matrix and project the velocity vector. But you have to pay attention also to how surface normals are defined in such a case, since they are vector too, you should take it into account in the new system of reference. So probably turning the CAD can be the most straightforward way.
But can't I just calculate it as if I didn't have an inflow angle and add both, which should give me the resulting force vector? And then I can just take out the drag and lift components depending on my own frame of reference.
It can be a solution, it should work. You can calculate lift & drag for a 0 angle geometry and inflow, then rotate both the geometry and the flow inclination and use your approach to verify if it works.
You’re amazing bro 😱😱😱😱😱😰🤩🤩🤩🤩🤩🤩 you save me and my tesis project. Thanks!!!!
Hi, Thanks for this tutorial.
In my case I am not able to select a specific boundary surface as you did: The data hierarchy is set on Multi-block dataset. I can just select Fluid domain and a general Boundary.
Do you know how I can solve this issue?
All the best
Hello I am also facing the same problem..did you find a solution to it..
I know this is old, but the solution is selecting openfoam reader from just above where the extract block filter appears in the tree in the top left and making sure the cut or wall that represents the aircraft is selected then hitting apply
Hi! Thanks for the video. I would like to make you a question. For the incomprensible case, the pressure is usually not in [Pa] but it is divided by the fluid density (so the unit is m^2/s^2). On that case should we multiply the pressure for the density in order to have the proper pressure? (and the proper forces).
Second question. I am calculating the forces exchanged between a boat hull and the water (so density=1000 kg/m^3). Should I use the same formula multiplied by the water density or should I use the same formula? Thanks in advance for the answer!
Yeap, u r right
one need to muliply pressure by density, to get actual force value
where can I d/l the openFOAM_2834.case from?
I think this will give normal force and axial force. Not lift and drag.
I think I agree with you, but I am not sure. To get the total lift force the pressure load on the mesh face should be multiplied with the mesh face area.
@@lucderuiter8904 To be more precise, if you change angle of attack with velocity vectors this procedure will give Normal and Axial force. On the other hand, if you change angle of attack by body rotation it wil give Lift and drag force.
So, the tutorial doesnt give dragCoeff? How can I obtain dragCoeff?
Hello great tutorial !!
by the way which solver in OpenFOAM did you used to run your simulation...
May I ask how i could extract the spanwise lift distribution before integrating, in order to adapt the wingplanform and obtain a bell shaped lift distribution in openfoam?
by this way aren't you neglecting shear forces?
well, in CFD everything is calculated and then it is up to the user considering or not these effects
Thank you, it helps a lot. But, can you tell how to calculate lift and drag with AoA variant?
Thanks before :)
Thank you for video sir. But how to find lift and drag for the different angle of attack using paraview?
Sorry for the late reply. Anyway, the procedure in paraview is exactly the same. The only thing you have to change in your CFD simulation is the geometry configuration!
Obviously, all theese things cost a lot, if we exclude the student licences?
I'd like to have something like this to compile videogame cars' datas
Hello
it is very a important tutorial. Can you please upload case directory so I may download and practice. Shall be very grateful. Thanks
Thank you very much sir. Super usefull!
quillo vaya acento que tienes compare
hi.. could you do a tut on the workflow i should take starting with a fresh model from a 3d suite like Blender all the w
ay to visualizing aerodynamic airflow? thanks in advance
yeah, STL are easy to import in our web application. If you want we can set up a custom tutorial for you!