|
[Sponsors] |
May 18, 2010, 03:37 |
A wall has been placed
|
#1 |
Senior Member
Join Date: Mar 2009
Posts: 138
Rep Power: 17 |
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 |
|
May 18, 2010, 07:57 |
|
#2 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
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. |
|
May 18, 2010, 08:50 |
|
#3 |
Member
Join Date: Jun 2009
Posts: 56
Rep Power: 16 |
have you used "outlet" or "opening" boundary conditions?
|
|
May 19, 2010, 03:32 |
|
#4 |
Senior Member
Join Date: Mar 2009
Posts: 138
Rep Power: 17 |
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 |
|
May 19, 2010, 18:28 |
|
#5 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
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.
|
|
May 21, 2010, 04:05 |
|
#6 |
Senior Member
Join Date: Mar 2009
Posts: 138
Rep Power: 17 |
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 Could you please lift the fog! Thanks |
|
May 21, 2010, 04:10 |
|
#7 |
New Member
Arsene Noume
Join Date: May 2010
Posts: 4
Rep Power: 15 |
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 |
|
May 21, 2010, 06:35 |
|
#8 | |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
Quote:
|
||
May 21, 2010, 08:52 |
|
#9 | |
Senior Member
Attesz
Join Date: Mar 2009
Location: Munich
Posts: 368
Rep Power: 17 |
Quote:
|
||
May 22, 2010, 06:53 |
|
#10 | |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
Quote:
|
||
May 28, 2010, 04:59 |
|
#11 |
Senior Member
Join Date: Mar 2009
Posts: 138
Rep Power: 17 |
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! |
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
[Commercial meshers] Fluent3DMeshToFoam | simvun | OpenFOAM Meshing & Mesh Conversion | 50 | January 19, 2020 15:33 |
help with wall functions | Nick Georgiadis | Main CFD Forum | 10 | January 17, 2017 10:03 |
Errors running allwmake in OpenFOAM141dev with WM_COMPILE_OPTION%3ddebug | unoder | OpenFOAM Installation | 11 | January 30, 2008 20:30 |
AMG versus ICCG | msrinath80 | OpenFOAM Running, Solving & CFD | 2 | November 7, 2006 15:15 |
Multicomponent fluid | Andrea | CFX | 2 | October 11, 2004 05:12 |