Ahmed body

Ahmed body and its importance:

1. Its shape is simple enough to allow for accurate flow simulation but retains some important practical features relevant to automobile bodies.

2. The special shape enables the Ahmed body tp to be used widely to validate new computational fluid dynamics code. This can be done by comparing the results of the new code with that of previously established experimental data.

RESULTS

CASE 1 (DEFAULT MESH)

At the first case, meshing is done with default parameters (413.66 mm) without any inflation layers. Meshing for this first case is :

Ahmed body car wall pressure:

VELOCITY VECTOR:

VELOCITY CUT PLANE:

VELOCITY CONTOUR :

RESIDUALS

CASE-2 (REFINED MESH)

MESHING FACE SIZING:

MESHING HOLE SIZING

MESHING INFLATION LAYERS:

VELOCITY CONTOUR:

RESIDUALS :

PRESSURE CONTOUR :

A negative value of static pressure indicates that pressure values are lower than the gauge pressure provided those particular points. Since in two cases, gauge pressure is taken as zero there might be possible of negative static pressure. But we have to make sure that absolute pressure value is positive if not there is some problem with boundary conditions and initial conditions. For instance, I ran the same setup with a gauge pressure of 1503.8 k pascal and corresponding static pressure shown in below