Flow around a cone-shaped piston

Update: June 1, 2017
OpenFOAM 4.x

Case directory

$FOAM_TUTORIALS/incompressible/pimpleDyMFoam/movingCone

Summary

We wll calculate the flow around a cone-shaped piston moving in a cylindrical tube. The calculation is performed using a simplified model in which a portion of the cylinder is cut out in a wedge shape as one layer mesh.

Model Model

The region "left" is set to be open for fluid to flow in and out, the cylinder surface is set to no-slip wall condition, and the piston surface (region "movingWall") is set to have a fixed flow velocity (0, 0, 0). The piston moves from the region "left" to the region "fixedWall" at 1 m/s. The motion of the mesh is specified in the files constant/dynamicMeshDict and 0/pointMotionUx as follows.

dynamicFvMesh   dynamicMotionSolverFvMesh;
motionSolverLibs ( "libfvMotionSolvers.so" );
solver          velocityComponentLaplacian;
velocityComponentLaplacianCoeffs
{
    component       x;
    diffusivity     directional (1 200 0);
}
File: constant/dynamicMeshDict
dimensions      [0 1 -1 0 0 0 0];
internalField   uniform 0;
boundaryField
{
    movingWall
    {
        type            uniformFixedValue;
        uniformValue    constant 1;
    }
    farFieldMoving
    {
        type            slip;
    }
    fixedWall
    {
        type            uniformFixedValue;
        uniformValue    constant 0;
    }
    left
    {
        type            uniformFixedValue;
        uniformValue    constant 0;
    }
    farField
    {
        type            slip;
    }
    back
    {
        type            wedge;
    }
    front
    {
        type            wedge;
    }
}
File: 0/pointMotionUx

By including the file system/cuttingPlane in the file system/controlDict, the "value of the specified plane" at each time is output to the directory postProcessing/cuttingPlane.

The meshes are as follows.

Mesh at time 0 Mesh at time 0

The calculation result is as follows.

Mesh movement
Flow velocity (U)
Flow velocity at final time (U) Flow velocity at final time (U)
Pressure at final time (p) Pressure at final time (p)

Commands

cp -r $FOAM_TUTORIALS/incompressible/pimpleDyMFoam/movingCone movingCone
cd movingCone

blockMesh
pimpleDyMFoam

paraFoam

Calculation time

  • 16.54 seconds *Single, Inter(R) Core(TM) i7-2600 CPU @ 3.40GHz 3.40GHz

Reference