[NEMO] Divergence for two-directional flow
Hi pals!
I am trying to analyse Falcon 9 along its reentry trajectory. To simply the simulation, I'm having a simplified model with one nozzle at the moment in Argon environment. There are two main parts: 1. Descent w/o plume 2. Descent w plume For part 1, there are no issues with it and the results are fine. For part 2, I configure the Argon freestream and added MARKER_SUPERSONIC_INLET at the nozzle exit with negative x-velocity component but it diverges immediately. Code:
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------------------------------ Begin Solver ----------------------------- Mesh file: https://drive.google.com/file/d/1vtG...ew?usp=sharing |
Hi Jessowy,
Thanks for using SU2-NEMO! It seems like an interesting problem and look forward to seeing the results. As a quick heads-up, I can't see any of the mesh files - I no longer have access to all my tools. Your setup looks good. Some things I would suggest are: 1.) Run using the AUSM or MSW numerical scheme. In my experience, they were much more stable. 2.) I would make sure you are running to a first-order simulation to start (MUSCL=NO). I think the difficulty is arising due to the nozzle exit flow condition. The numerics, at the beginning of the simulation, see a velocity gradient of M=4.5 flow to a negative value....which I suspect is causing problems. You can play some games here: 1.) You can use a restart file. Take you good solution from your first solution, then apply the nozzle condition. 2.) You can create/alter your restart file to better initialize the flow. You can manually change the restart csv file to include a plume region where the flow state would more closely resemble the plume. This may alleviate the large gradients. 3.) Finally, (I think this would work - but not confident), is to set your freestream conditions to stationary flow (or close to it). Then the inflow of your domain and the nozzle exit would be initialized as a supersonic inlet. This will allow the plume to develop before interacting with the M=4.5 flow. You may need to run the problem unsteady for this. I am not aware of anyone trying to simulate any type of retro-propulsion with SU2 in general, so you are in uncharted territory. Please let me know if any of this helps. Wally |
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