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

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.