Contents | Description | Calculation | Results


Description of the case

In order to learn and to have a better idea on the functionning of the code AVBP, a case test calculation was performed: the calculation of a bump.

This case is well documented and there are four standards cases:

subsonic flow at M=0.01 and a 4.2% bump

subsonic flow at M=0.3 and a 4.2% bump

transonic flow at M=0.85 and a 4.2% bump

supersonic flow at M=1.4 and a 4.0% bump

The height of the channel is 1 and the bump is formed by a circle with a radius of 1. The thickness of the circle is a percentage of the height of the bump.

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Performed calculation

The transonic case was calculated with a standard bump mesh.

In this case we took the following characteristics:

M=0.85

number of iterations: 10,000

Normally, the flow looks like the flow around an airfoil. The flow must be distended on the rear part of the bump until the Mach number value is 1.35. Then a little shock wave must occur.

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Results

With the simulation of the case, the awaited results could be observed, as shown in the pictures below (click on the pictures to enlarge them):

Mach number

Pressure

Density

(These pictures were obtained by means of dplot, the AVBP postprocessor)


Mach number

The shock can be observed at the rear part of the bump, as previously said. The global values are respected: the mach number is 1.3 in this area.

Pressure

The acceleration of the fluid can be clearly observed by the pressure diminution in the converging part of the mesh.

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