Backstep flow with inflow distribution

Update: June 1, 2017
OpenFOAM 4.x

Case directory

$FOAM_TUTORIALS/incompressible/simpleFoam/pitzDailyExptInlet

Summary

The fluid flows in from the region "inlet" and out from the region "outlet". A no-slip condition is set for the channel walls, and the problem is solved in 2 dimensions with a single mesh in the Z direction. The standard k-ε model is used as the turbulence model.

Model geometry Model geometry

The distributions of flow velocity (U), turbulence energy (k), and turbulence dissipation rate (ε) entering from the region "inlet" are specified by value in each coordinate. These distributions are defined in a file under the directory constant/boundaryData/inlet.

Distributions of inlet flow velocity Distributions of inlet flow velocity
Distributions of inlet turbulence energy Distributions of inlet turbulence energy
Distributions of inlet turbulence dissipation rate Distributions of inlet turbulence dissipation rate

To use the defined distribution data in the calculation, we set the type of the region "inlet" to "timeVaryingMappedFixedValue" in the file 0/U, 0/k and 0/epsilon.

The meshes are as follows.

Mesh Meshes

We use the streamlines function to draw streamlines during the calculation. The configuration is done in the file system/controlDict.

The streamline data is saved as a vtk format file under the directory postProcessing/sets/streamLines at each time. This file can be loaded into ParaView to visualize the streamlines.

To visualize the calculated turbulence energy and turbulence dissipation rate, check "k" and "epsilon" in the "Properties" tab in ParaView.

Check k and epsilon Check "k" and "epsilon"

The calculation result is as follows.

Flow velocity (U) Flow velocity (U)
Pressure (p) Pressure (p)
Turbulent energy (k) Turbulent energy (k)
Turbulent dissipation rate (epsilon) Turbulent dissipation rate (epsilon)
Streamlines by streamlines function Streamlines by streamlines function

Commands

cp -r $FOAM_TUTORIALS/incompressible/simpleFoam/pitzDailyExptInlet pitzDailyExptInlet
cd pitzDailyExptInlet

blockMesh
simpleFoam

paraFoam

The file system/decomposeParDict is provided so that parallel execution is possible.

cp -r $FOAM_TUTORIALS/incompressible/simpleFoam/pitzDailyExptInlet pitzDailyExptInlet
cd pitzDailyExptInlet

blockMesh
decomposePar
foamJob -parallel simpleFoam
reconstructPar

paraFoam

The calculation will be executed in 4 parallels by the settings in system/decomposeParDict. The calculation run in the background, and the execution log is output to the file "log".

Calculation time

25.88 seconds (single)

14.49 seconds (4 parallels)

※Inter(R) Core(TM) i7-2600 CPU @ 3.40GHz 3.40GHz

Reference