Axisymmetric subsonic flow and shock diamonds

Update: December 17, 2018
OpenFOAM 4.x

Case directory

$FOAM_TUTORIALS/compressible/rhoCentralFoam/LadenburgJet60psi

Summary

The subsonic air flow from a portion of the end face of a wedge-shaped region is performed for 2 × 10-5 seconds.

The gas flows in from the region "inlet" at 315.6 m/s and out from the region "outlet". The region "freestreaminlet" is set to a no-slip wall and the region "freestream" is set to free-flowing. And axisymmetric boundary conditions are set to regions "wedge1" and "wedge2" that are parallel to the flow direction.

Model geometry Model geometry

The turbulence model is not used, and the calculation is performed as a pseudo 2-dimensional mesh with one mesh in the circumferential direction of the wedge.

The meshes are as follows, and the number of mesh is 1800.

Mesh Meshes

The calculation result is as follows.

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

We can see that a shock diamond is generated behind the flow.

Commands

cp -r $FOAM_TUTORIALS/compressible/rhoCentralFoam/LadenburgJet60psi LadenburgJet60psi
cd LadenburgJet60psi

blockMesh
decomposePar
mpirun -np 8 rhoCentralFoam -parallel
reconstructParMesh -mergeTol 1e-07
reconstructPar

paraFoam

A converged solution is used as the initial condition. If you want to start the calculation with no flow, you need to overwrite folder 0 with the files in folder 0.orig and then run the solver.

Calculation time

  • 19.45 seconds (from the converged solution)
  • 24.93 seconds (from no flow)

*8 parallel, Inter(R) Core(TM) i7-8700 CPU @ 3.20GHz 3.19GHz

Reference