[k.vimalakanthan]

Hi All,

I have a differing number of vanes the impeller and diffuser and I couldn't use the standard 'no-ordering' AMI from the of230 (SimpleFoam with fvOptions), so I though I try the mixing plane interface in foam-extend 3.1 (MRFSimpleFoam). I'm very new to openfoam, but fe31 seems to much harder to get it going I'm keep getting 'Floating point exception (core dumped)' (see below). I'm not sure what is wrong with the set up, because same case went fine on the of230. This case has no pitch change too, so it should work fine if the different flow area is the problem.

You can download the entire case directory at (http://efshare.com/?s=89JF75) or the main files are attached to this thread AnsysMesh.zip, could any of you please have a look at this and see if you can spot the error? I'm sure its something very obvious to someone who is used to fe31...

Can anyone please also suggest if there is a way to use circumferential averaging interface (such as the stage interface in cfx) in of230? SimpleFoam with FVOptions seems to be the easiest way to simulate this type of problem, but it lacks the maxing plane interface for rotor/stator with different pitch. Eventually I will be moving on to compressible radial rotor/stator simulations with differing pitch, so please add any of your suggestions regarding this type of simulation in OpenFOAM...

Any advice is greatly appreciated,
Thanks in advance,
Kishore

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | foam-extend: Open Source CFD                    |
|  \\    /   O peration     | Version:     3.1                                |
|   \\  /    A nd           | Web:         http://www.extend-project.de       |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build    : 3.1-1dd681f6e943
Exec     : MRFSimpleFoam
Date     : Jul 14 2015
Time     : 12:41:21
Host     : ubuntu-VirtualBox
PID      : 12391
CtrlDict : /home/ubuntu/foam/foam-extend-3.1/etc/controlDict
Case     : /media/sf_OpenFoamUser/run/fe31/AnsysMesh
nProcs   : 1
SigFpe   : Enabling floating point exception trapping (FOAM_SIGFPE).

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0

Initializing the GGI interpolator between master/shadow patches: DiffPer1/DiffPer2
Initializing the GGI interpolator between master/shadow patches: RotorPer1/RotorPer2
Initializing the GGI interpolator between master/shadow patches: InPer1/InPer2
Initializing the mixingPlane interpolator between master/shadow patches: Diff2Rotor/Rotor2Diff
Initializing the mixingPlane interpolator between master/shadow patches: Rotor2In/In2Rotor
Reading field p

Reading field U

Reading/calculating face flux field phi

Selecting incompressible transport model Newtonian
Selecting RAS turbulence model RNGkEpsilon
RNGkEpsilonCoeffs
{
    Cmu             0.0845;
    C1              1.42;
    C2              1.68;
    alphak          1.39;
    alphaEps        1.39;
    eta0            4.38;
    beta            0.012;
    sigmak          0.71942;
    sigmaEps        0.71942;
}


Starting time loop

Creating ggi check function object
Creating mixingPlane check functionObject
Time = 1

BiCGStab:  Solving for Ux, Initial residual = 1, Final residual = 0.0388652, No Iterations 1
BiCGStab:  Solving for Uy, Initial residual = 1, Final residual = 0.0441579, No Iterations 1
BiCGStab:  Solving for Uz, Initial residual = 1, Final residual = 0.0342605, No Iterations 1
Floating point exception (core dumped)

[k.vimalakanthan]

The error was due to incorrectly setup mixing plane ribbon patch, now that is fixed the simulations seems to be running okay. I hope this thread help others wanting to simulate radial turbo machines in OpenFOAM. Now I'm off to test some compressible flows...wish me luck

Please still advice/suggest me on simulation regarding radial turbo machines with differing pitch and compressible flows using OpenFOAM....

[tareqkh]

Hello Vimalakanthan,

Do you have the case file of the problem?

Thanks,