[egerland]

Hi,

I don't know how to set an outlet velocity field result of a previous run as inlet velocity field in my present run.
Can anybody help me
Thanx

[NorbertB]

Hi,

You can try that (in your system file):

startFrom lastTime;

[egerland]

Hi Norbert,

I have a case, in which my inlet (O/U) of the boundaryField is fixedValue, uniform (10 0 0).
my outlet is set to zeroGradient.
In a next case, I want to take the results of the outlet velocity field and set them as the boundary field of the inlet for the new case. Instead of fixedValue, I want to use the results of the old case.

[MartinB]

Hi Benni,

have a look at the mapFields utility: in the mapFieldsDict you can use the patchMap function.

http://www.openfoam.com/docs/user/mapFields.php

In your case the entry for patchMap might be:

patchMap (outlet inlet);

Preparations:
- define the appropriate mapFieldsDict in your second simulations "system" directory.
- use boundary condition fixedVelocity for the inlet of your second simulation with a dummy value of (0 0 0) initialized.

The command sequence is something like (replace the paths and the 1000):
cd path_to_second_simulation
mapFields path_to_first_simulation -sourceTime 1000

Check with paraview before starting the second simulation.

Martin

[egerland]

Hi Martin,

thanx for your help.

I tried the second simulation with mapFieldsDict. The Field in paraview is o.k.

But I get the following error:

gradientInternalCoeffs cannot be called for a genericFvPatchField (actual type fixedVelocity)
on patch inlet of field U in file "/home/eggert/OpenFOAM/eggert-1.6/run/cube_cyclic/0/U"
You are probably trying to solve for a field with a generic boundary condition.

From function genericFvPatchField<Type>::gradientInternalCoeffs( ) const
in file fields/fvPatchFields/basic/generic/genericFvPatchField.C at line 782.

FOAM exiting


The other point is: I think mapFields is perhaps not the right tool for what I want to do. I have a 2-D case with inlet on the left and outlet on the right. In the middle of the mesh I have a box, which stands for a wall in a 3D case.
For every simulation step the velocity Field at the outlet would be the inlet for the next simulation step. This means, that this simulation will give the same solution as a simulation with many boxes in a row.
My problem is to generate the inlet velocity field for every step of the simulation.

[MartinB]

Hi Benni,

I assume that the cyclic boundary condition is the BC you are looking for.

Since I don't have experience with it, you may have a look at these threads:

http://www.cfd-online.com/Forums/ope...implefoam.html

http://www.cfd-online.com/Forums/ope...condition.html

This example in the OpenFOAMs tutorial directories might help, too:
tutorials/incompressible/channelFoam/channel395

Good luck

Martin

[Amar_CFD]

hi
I am also trying to simulate the same case. I have one pipe and valve as a first geometry. i want to give outlet velocity of the first case as inlet velocity distribution for second case which is simple pipe.
1)I tried using mapFields as follows
in second case directory
mapFields -path_to_first_case -sourceRegioin -outlet -targetRegion inlet

i also modified mapFieldDict in second_case/system as
patchMap (outlet inlet )

its showing the error
-FOAM FATAL ERROR
cannot find file "points" in directory first_case/outlet in times "latest_time_value down to constant.
please help.