Flow around a running motorcycle

Update: June 1, 2017
OpenFOAM 4.x

Case directory



We calculate the wind flow around a motorcycle. The fluid flows in at (20, 0, 0) m/s from the region "inlet" (minimum X-plane) and out at the region "outlet" (maximum X-plane). The surface of the motorcycle is assumed to be a no-slip wall condition, and the ground is assumed to have a velocity of (20, 0, 0) m/s. The other walls (region "upperWall", "frontAndBack") are assumed to be in the slip wall condition.

The k-ω SST is used for the turbulence model.

Model geometry (entire) Model geometry (entire)
Model geometry (near the motorcycle) Model geometry (near the motorcycle)

The meshes are as follows, and the number of mesh is 683240.

Mesh (entire) Mesh (entire)
Meshes (near the motorcycle) Meshes (near the motorcycle)
Meshes (XY-Plane) Meshes (XY-Plane)

The calculation result is as follows.

Flow velocity (U) Flow velocity (U)
Pressure (p) Pressure (p)


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

cp $FOAM_TUTORIALS/resources/geometry/motorBike.obj.gz constant/triSurface/
mpirun -np 6 snappyHexMesh -parallel -overwrite

# Search for the directory "processor*" and update the directory "0" in the found directory with 0.orig
ls -d processor* | xargs -I {} rm -rf ./{}/0
ls -d processor* | xargs -I {} cp -r 0.orig ./{}/0

mpirun -np 6 patchSummary -parallel
mpirun -np 6 potentialFoam -parallel
mpirun -np 6 simpleFoam -parallel

# Merge splited meshes and results
reconstructParMesh -constant
reconstructPar -latestTime


The utility patchSummary writes the patch information to standard output (the file is not modified). We also use potentialFoam to calculate the initial conditions for the flow velocity (U), and then perform the actual flow analysis.

Calculation time

  • Making meshes: 2 minutes 12.18 seconds
  • Calculating: 9 minutes 33.34 seconds

*6 parallel, Inter(R) Core(TM) i7-2600 CPU @ 3.40GHz 3.40GHz