|
[Sponsors] |
May 24, 2011, 20:30 |
residual spikes in fluent for airfoil case
|
#1 |
New Member
Mike
Join Date: Apr 2011
Posts: 22
Rep Power: 15 |
Hi,
Im running a test on an transonic airfoil at M=0.73 and Re=6.5E6 im using the density based solver in FLUENT and the spallart-allmares turlence model. I've been having a problem getting the solution to converge even with a low Courant number of 4 (which is low since using implicit solver) and low URF's around 0.2. The force monitors of the drag, lift and momentum do not converge before the equation's residuals begin to spike. The force monitors are what im most interested in since im looking at performance of the airfoil. I built the mesh in ICEM and noticed that the best results in fluent are gotten when the spacing of the first node off the wall is at y+=10 (limit S-A). Also when more nodes are added in the y-direction the case diverges in FLUENT. The y-velocity is begins spiking early durring the itterations and then the energy, x-velocity, and continuity join in later on. However the trubulance residual continues to converge. I was wondering what could be cousing these spikes. Heres a picture of the residuals plot starting at the 2000 iteration point when things start to go bad and thanks for all help Last edited by josip76; May 24, 2011 at 21:32. |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
icoLagrangianFoam OF1.6 myNewParticleSolver | heavy_user | OpenFOAM | 23 | June 2, 2020 03:18 |
How to write k and epsilon before the abnormal end | xiuying | OpenFOAM Running, Solving & CFD | 8 | August 27, 2013 16:33 |
Low Mach number Compressible jet flow using LES | ankgupta8um | OpenFOAM Running, Solving & CFD | 7 | January 15, 2011 14:38 |
Error log | vw.cfd | OpenFOAM | 6 | August 7, 2009 06:44 |
TurbFoam problemlarge Co number | sunnysun | OpenFOAM Running, Solving & CFD | 6 | March 10, 2009 09:05 |