# forwardStep tutorial case: failure in OpenFOAM-dev using rhoPimpleFoam

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May 3, 2022, 16:27
forwardStep tutorial case: failure in OpenFOAM-dev using rhoPimpleFoam
#1
New Member

Robert C
Join Date: May 2022
Posts: 1
Rep Power: 0
I am new to OpenFOAM, and am experimenting with various flavors of the solver, including OpenFOAM-6 and OpenFOAM-dev (CFD-Direct), and OpenFOAM-plus (ESI).

I am interested in compressible solvers, so for OpenFOAM-dev, I attemped to run the forward step problem (\$FOAM_PROJECT_DIR/tutorials/compressible/rhoPimpleFoam/laminar/forwardStep) using rhoCentralFoam and rhoPimpleFoam. To my surprise, rhoPimpleFoam failed with the below error message. I am posting here to see if I am missing something simple, ahead of filing a bug report with CFD Direct. I greatly appreciate any help you can provide.

Code:
```  Courant Number mean: 0.251275 max: 1.17915
Time = 0.016s

PIMPLE: Iteration 1
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver:  Solving for Ux, Initial residual = 0.0764808, Final residual = 1.29e-06, No Iterations 1
smoothSolver:  Solving for Uy, Initial residual = 0.064002, Final residual = 7.94223e-06, No Iterations 1
smoothSolver:  Solving for e, Initial residual = 0.26368, Final residual = 4.9006e-06, No Iterations 3
smoothSolver:  Solving for p, Initial residual = 0.0715941, Final residual = 6.77228e-08, No Iterations 2
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 1.94255e-09, global = 1.06042e-09, cumulative = 6.6211e-09
PIMPLE: Iteration 2
smoothSolver:  Solving for Ux, Initial residual = 0.00795199, Final residual = 9.99449e-11, No Iterations 1
smoothSolver:  Solving for Uy, Initial residual = 0.021992, Final residual = 1.56364e-09, No Iterations 1
smoothSolver:  Solving for e, Initial residual = 0.285134, Final residual = 2.3536e-08, No Iterations 2

--> FOAM FATAL ERROR:
Negative initial temperature T0: -3.09503```
I see no such error using rhoCentralFoam, nor in OpenFOAM-6 using sonicFoam, nor in OpenFoam-plus using sonicFoam.

Looking at the git log, I see the following commit which may be related:
Quote:
 commit 3341f925108a759f58f06ce2fd865321af6dd6ca Author: Henry Weller Date: Wed Jun 6 11:07:45 2018 +0100 sonicFoam, sonicDyMFoam, sonicLiquidFoam: Functionality merged into rhoPimpleFoam The sonicFoam, sonicDyMFoam and sonicLiquidFoam functionality has been merged into the transonic option of the latest rhoPimpleFoam solver and the corresponding tutorials moved into the rhoPimpleFoam tutorials directory. To run rhoPimpleFoam in transonic mode set the transonic option in the PIMPLE sub-dictionary of fvSolution: PIMPLE { . . . transonic yes; }
I have checked, and the transonic option is indeed present in fvSolution for forwardStep.

FWIW, I am using OpenFOAM-dev at commit 38262243ccdd13bd936541d2373ccfd1974db597

Last edited by RobertC; May 4, 2022 at 09:36.

 September 12, 2022, 12:23 #2 New Member   jay Join Date: Sep 2022 Posts: 2 Rep Power: 0 I concur that this case, as packaged in OpenFOAM 10 (installed 1 or 2 months ago from CFD Direct), encounters the negative temperature error. I can overcome the error when adding the following lines to the file 'system/controlDict'. adjustTimeStep yes; maxCo 0.7; maxDeltaT 1; However, the process time step becomes very small, ~2e-08.

 September 12, 2022, 13:44 #3 Senior Member   Domenico Lahaye Join Date: Dec 2013 Posts: 720 Blog Entries: 1 Rep Power: 17 Use limiter on T using https://www.openfoam.com/documentati...mperature.html Nothing in rhoSimpleFoam prevents negative T values, especially in initial stages of convergence. The issues has been repeated discussed in this forum. Good luck.

 June 17, 2023, 11:29 #4 New Member   jay Join Date: Sep 2022 Posts: 2 Rep Power: 0 The issue I had was addressed by OpenFOAM.org Issue 3889.

 Tags compressible, pimple, tutorial