Keep producing good work like this. Genuinely one of the only CFD videos that explains the whole process well. Thank you so much for making this video. Perhaps simulating an Aerospike nozzle could be you're next video at different altitudes (atmospheric pressures). So that we can see the change in the exhaust diameter as the nozzle climbs in altitude. Also using OpenFoam may appeal to a wider audience. So, if you could possible use that that would really be appreciated Josh (if possible ). I've never actually left a comment on RUclips before but I guess this is what it took. A good CFD tutorial that was actually well produced. Anyways look forward to the Aerospike nozzle vid dude. :D
Thanks for the kind comment! Simulating the aerospike is definitely something I'll be looking into doing at some point. I just need to update my MoC code to design it, since it's slightly different than the CD nozzle design. I probably won't do any OpenFoam tutorials, since SU2 is also open source and it's easier for me to stick to one program. I'm really just using SU2 to show some interesting results that I've simulated, and then I'm going to move onto how to program a CFD program from scratch. I'm glad I could get your first comment!
Hi Josh, I am blown away by your love for nozzles...And in-depth understanding. I am coming from field of coldspray metal 3d printing. Here we have added fun with loading of large fraction particles. Did you try any of that? Can you carryout paid consulting to optimise some of our. Nozzle projects? Thanks Josh.
It's a pretty cool topic! I have some more interesting CFD-to-analytical comparisons coming up, along with some videos on how to actually code the CFD solvers.
Thanks for this, Josh. I soon will be doing more CFD stuff in the coming years. One of my professors recommended I start with SU2. If possible, I do think it may be helpful if you did a video of how to build the .cfg file for the specific simulation. There are many options in the .cfg file that I do not understand. Anyway, thank you for all the SU2 and GMSH tutorials you have done. They are extremely helpful. I look forward to more.
You're welcome! The CFG file can be a bit lengthy for sure. For the most part, you can leave a lot of the settings at their default values, and only mess around with the boundary conditions (markers) and the freestream/farfield stuff. I would need to delve more deeply into all the different settings to be able to make a good video about it, and I don't have the time at the moment. When I made these CFG files for my videos, I downloaded their master CFG file from the GitHub and deleted all the sections that I didn't need. The SU2 tutorials they have on their GitHub are quite good, so I would browse through those to start off with. The folks that develop and maintain the code also seem to be really responsive with answering questions on their forum, so if you have specific questions, you can probably get them to answer you directly.
3:15 in plot the nozzle exit diameter is 6 (-3 to 3) and throat diameter is 2 (-1 to 1). So expansion ratio A/A* is (6/2)^2 = 9. But in the matlab command window the results showing A/A* [MOC] = 2.98714. Why is this discrepancy? Result in the command window matches Quasi 1-D isentropic result of A/A*, which is 3, but the plot does not agree.
Hey, your MOC code output shows the area ratio to be around 6.7 for exit mach = 3.5, but the output figure gives a y coordinate of 6.78, which makes area ratio 45. I tried to write my own moc code and I have the same issue. Why is this? Really appreciate all your work by the way.
Thanks! I don't really do unsteady simulations so I'm probably not the best person for the job, unfortunately. The SU2 tutorials are really good, so you might find something useful there.
Thanks a lot Josh, your videos are extremely helpful for cfd enthusiasts. I used the same mesh but when I ran the simulation in SU2 it results in an error "Orthoganization Failed, Linear Solver Diverged". Then I looked into its Mesh Quality Metrics, where the min and max orthogonality angle are -nan. I would like to know did you face any such problems during the simulation of the nozzle in SU2? Do you have any idea how to resolve it? Once again, thanks a lot for your videos, it has been really helpful.
You can include those effects in SU2 using the Navier-Stokes solver if you want to. The point of this video is to show how you can run a simple, quick CFD simulation for a rocket nozzle and compare it to the quasi 1D solutions that I go over in my other videos. The reason I use the Euler solver for this problem is because the quasi 1D solutions are inviscid.
The area ratio is supposed to be 3, but the output figure shows exit radius as 3 and throat radius as 1 making the area ratio 9. Why is this? I've written a code for MOC and my output is exactly the same as yours. Any clue why does this happen with moc? Thank you.
Hi Josh, I am very appreciated for this nice series on cfd. Is the su2 mesh file used in this video compatible with SU26.0 version? I have to try to change some lines in cfg file and, run 5 iterations. Then try to plot in Paraview 5.6 and I get only a line which is clearly not nozzle. I guess I missing sth.
The mesh should be fine since they didn't change its formatting from version 5 to 6. I would guess that it's a problem with the config file. Make sure the boundary markers match the mesh file names exactly.
Thanks! My code is on my GitHub (github.com/jte0419/Rocket_Nozzle_Design). After I finish my current set of panel method videos, I'm going to be doing the full derivation of this code. Just be aware of its limitations. If you want more details on all the different types of MoC formulations, check out the book by Zucrow and Hoffman.
@@JoshTheEngineer 3:15 in plot the nozzle exit diameter is 6 (-3 to 3) and throat diameter is 2 (-1 to 1). So expansion ratio A/A* is (6/2)^2 = 9. But in the matlab command window the results showing A/A* [MOC] = 2.98714. Why is this discrepancy? Result in the command window matches Quasi 1-D isentropic result of A/A*, which is 3, but the plot does not agree.
After some attempts, I was finally able o run this case with SU2 version 5.0.0 'Raven' and obtained similar results as Josh. I have used the same setup as him for most parts (including his Matlab code to generate a geometry), except for the following: - Mesh size: Josh's (17101 points, shown at 5:11 of video) x mine (13032 points) - Josh's .cfg line 47 (3:46 of video): FREESTREAM_TEMPERATURE changed from '3000.0' to '2965' (according to T* calculated with his MATLAB code) - Josh's .cfg line 168 (4:19 of video): Option 'SPATIAL_ORDER_FLOW = 1ST_ORDER' replaced by 'MUSCL_FLOW= NO' to use 1st order convection scheme In case anyone is also trying to solve this, I have created a github repository with mesh, configuration and results files: github.com/murillo-sspn/SU2_Rocket_Nozzle
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Keep producing good work like this. Genuinely one of the only CFD videos that explains the whole process well. Thank you so much for making this video. Perhaps simulating an Aerospike nozzle could be you're next video at different altitudes (atmospheric pressures). So that we can see the change in the exhaust diameter as the nozzle climbs in altitude.
Also using OpenFoam may appeal to a wider audience. So, if you could possible use that that would really be appreciated Josh (if possible ).
I've never actually left a comment on RUclips before but I guess this is what it took. A good CFD tutorial that was actually well produced.
Anyways look forward to the Aerospike nozzle vid dude. :D
Thanks for the kind comment! Simulating the aerospike is definitely something I'll be looking into doing at some point. I just need to update my MoC code to design it, since it's slightly different than the CD nozzle design. I probably won't do any OpenFoam tutorials, since SU2 is also open source and it's easier for me to stick to one program. I'm really just using SU2 to show some interesting results that I've simulated, and then I'm going to move onto how to program a CFD program from scratch. I'm glad I could get your first comment!
Hi Josh, I am blown away by your love for nozzles...And in-depth understanding. I am coming from field of coldspray metal 3d printing. Here we have added fun with loading of large fraction particles. Did you try any of that? Can you carryout paid consulting to optimise some of our. Nozzle projects? Thanks Josh.
Very interesting stuff! I'm looking forward to this topic at university!
It's a pretty cool topic! I have some more interesting CFD-to-analytical comparisons coming up, along with some videos on how to actually code the CFD solvers.
Yeah, I am watching your older videos right now to keep up! (New to the channel, love it!)
Thanks for this, Josh. I soon will be doing more CFD stuff in the coming years. One of my professors recommended I start with SU2.
If possible, I do think it may be helpful if you did a video of how to build the .cfg file for the specific simulation. There are many options in the .cfg file that I do not understand.
Anyway, thank you for all the SU2 and GMSH tutorials you have done. They are extremely helpful. I look forward to more.
You're welcome! The CFG file can be a bit lengthy for sure. For the most part, you can leave a lot of the settings at their default values, and only mess around with the boundary conditions (markers) and the freestream/farfield stuff. I would need to delve more deeply into all the different settings to be able to make a good video about it, and I don't have the time at the moment. When I made these CFG files for my videos, I downloaded their master CFG file from the GitHub and deleted all the sections that I didn't need.
The SU2 tutorials they have on their GitHub are quite good, so I would browse through those to start off with. The folks that develop and maintain the code also seem to be really responsive with answering questions on their forum, so if you have specific questions, you can probably get them to answer you directly.
3:15 in plot the nozzle exit diameter is 6 (-3 to 3) and throat diameter is 2 (-1 to 1). So expansion ratio A/A* is (6/2)^2 = 9. But in the matlab command window the results showing A/A* [MOC] = 2.98714. Why is this discrepancy? Result in the command window matches Quasi 1-D isentropic result of A/A*, which is 3, but the plot does not agree.
Hey, your MOC code output shows the area ratio to be around 6.7 for exit mach = 3.5, but the output figure gives a y coordinate of 6.78, which makes area ratio 45.
I tried to write my own moc code and I have the same issue. Why is this?
Really appreciate all your work by the way.
Congrats! You have amazing videos. I wonder if you could make a video on SU2 using unsteady simulations... Thanks a lot!
Thanks! I don't really do unsteady simulations so I'm probably not the best person for the job, unfortunately. The SU2 tutorials are really good, so you might find something useful there.
Thanks a lot Josh, your videos are extremely helpful for cfd enthusiasts. I used the same mesh but when I ran the simulation in SU2 it results in an error "Orthoganization Failed, Linear Solver Diverged". Then I looked into its Mesh Quality Metrics, where the min and max orthogonality angle are -nan. I would like to know did you face any such problems during the simulation of the nozzle in SU2? Do you have any idea how to resolve it? Once again, thanks a lot for your videos, it has been really helpful.
The exit mach no and area ratio obtained is not matching and is following area ratio-mach no trend.
Great videos!. Your config file site is not working. Could you please make it available? Thanks very much!
Thanks! I should have fixed my website for now, so you should be able to find it there again.
Wouldn't you rather use a commercial CFD package which incorporates the effects of viscosity and turbulence for a more precise simulation?
You can include those effects in SU2 using the Navier-Stokes solver if you want to. The point of this video is to show how you can run a simple, quick CFD simulation for a rocket nozzle and compare it to the quasi 1D solutions that I go over in my other videos. The reason I use the Euler solver for this problem is because the quasi 1D solutions are inviscid.
The area ratio is supposed to be 3, but the output figure shows exit radius as 3 and throat radius as 1 making the area ratio 9. Why is this?
I've written a code for MOC and my output is exactly the same as yours. Any clue why does this happen with moc?
Thank you.
Any idea how you would go about plotting characteristic curves from the cfd data? I.e. lines whose normal Mach number is constant at M=1
Hi Josh, I am very appreciated for this nice series on cfd.
Is the su2 mesh file used in this video compatible with SU26.0 version? I have to try to change some lines in cfg file and, run 5 iterations. Then try to plot in Paraview 5.6 and I get only a line which is clearly not nozzle. I guess I missing sth.
The mesh should be fine since they didn't change its formatting from version 5 to 6. I would guess that it's a problem with the config file. Make sure the boundary markers match the mesh file names exactly.
Wow just fantastic! Any chance you would be willing to share your MOC matlab code?
Thanks! My code is on my GitHub (github.com/jte0419/Rocket_Nozzle_Design). After I finish my current set of panel method videos, I'm going to be doing the full derivation of this code. Just be aware of its limitations. If you want more details on all the different types of MoC formulations, check out the book by Zucrow and Hoffman.
@@JoshTheEngineer 3:15 in plot the nozzle exit diameter is 6 (-3 to 3) and throat diameter is 2 (-1 to 1). So expansion ratio A/A* is (6/2)^2 = 9. But in the matlab command window the results showing A/A* [MOC] = 2.98714. Why is this discrepancy? Result in the command window matches Quasi 1-D isentropic result of A/A*, which is 3, but the plot does not agree.
Anyone has a link to the configuration file?
Sir, do u have a lecture on MOC method?
Not yet, but when I'm done with my panel method videos, I was going to do a full MOC video series.
Thanks Sir.
Pls let me inform when you are going to start. I will be obliged to you for this.
Hello, Josh, could you provide the .cfg file? I believe that your website link is not working.
After some attempts, I was finally able o run this case with SU2 version 5.0.0 'Raven' and obtained similar results as Josh. I have used the same setup as him for most parts (including his Matlab code to generate a geometry), except for the following:
- Mesh size: Josh's (17101 points, shown at 5:11 of video) x mine (13032 points)
- Josh's .cfg line 47 (3:46 of video): FREESTREAM_TEMPERATURE changed from '3000.0' to '2965' (according to T* calculated with his MATLAB code)
- Josh's .cfg line 168 (4:19 of video): Option 'SPATIAL_ORDER_FLOW = 1ST_ORDER' replaced by 'MUSCL_FLOW= NO' to use 1st order convection scheme
In case anyone is also trying to solve this, I have created a github repository with mesh, configuration and results files:
github.com/murillo-sspn/SU2_Rocket_Nozzle
Is SU2 software available for all students or only for Stanford students??
I got the answer! thanks
Sorry for the delayed response. Glad you figured it out!