A wall has been placed
Hello Everybody,
I have a problem with a simulation in CFX. The Problem is: The geometry is as simple as that: a board with an ellipse at the beginning. In the middle of the board i have a hot aluminium plate. Three Free Slip walls, one Symmetry plane, Inlet, Outlet, 10e6 nodes, structured mesh I have already done a simulation with the following boundarys: - SST - Inlet: 10 (m/s), Tu = 0.1 ; l=10mm, 300K - Outlet: 0 Pa - Ansys V11 and it worked fine. Now I have the same case just with a little change, there is a wire behind the ellipse to increase turbulence. But now it isnt working at all, I get the message: - " A wall has been placed at portion(s) of an OUTLET..." - The maximum Mach number is about 10 - The Residuals drop to 1e-100 - The Result File is completely empty I have already changed a lot of parameters but nothing helped. Any Ideas, Solutions, deja vus? Any more informations? Thanks a lot Camoesas |
What is your reference pressure? If your outlet is 0 Pa then you will need a finite reference pressure or you will have problems.
The error message suggests the wire is causing convergence problems. A wire in high Ma flows is going to have shocks and rarefactions and all sorts of complex stuff happening so will be a lot harder to converge than high Ma flow over a flat plate. You will probably need to start with small time steps and increase them as the simulation proceeds. Also make sure your mesh quality is good. |
have you used "outlet" or "opening" boundary conditions?
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HI,
My reference Pressure is 101325 Pa. The Flow velocity should be 10 m/s, thus far far away from supersonic. For the Outlet I use outlet and not Opening Regards |
Then why are you running a compressible flow solver? You have to be using a compressible solver as it was talking about Mach numbers. Go back to an incompressible solver and I bet it converges just fine.
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Hey Glenn,
thats interesting, but after a lot of searching and aimless clicking in Ansys I still don't know where to choose compressible / incompressible solver! I can't remember ever seen such a menu :confused: Could you please lift the fog! Thanks |
Hello!
I'm simulating a centrifugal compressor and i have the same problem (a wall has been placed at portion of an outlet boudary condition...) I tried by setting a static pressure as outlet boundary condition but the situation persist. I just want to know if your problem has been solve, and how? it could help me. Thankyou |
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Hello Everybody,
Thank you for trying to help me. Now me Simulation is just running fine! It was the mesh indeed. I got a new one and now everything s fine! |
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