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TURBULENCE MODEL NUMERICAL ANALYSIS

3D Modified Bump-in-channel

This case is designed primarily for numerical analysis of turbulence model simulations; e.g., convergence properties, effect of order of accuracy, etc.

This case is almost the same as the 3D Bump-in-channel Verification case, except that the grid here is only half in spanwise extent of the original (because of symmetry, the results should be the same). A large sequence of nested grids of the same family are provided here if desired.

The 3D bump-in-channel case is a three-dimensional version of the 2D bump-in-channel verification case, with spanwise variation added. In this 3D case the z direction is "up" and y is "spanwise." It was run at M = 0.2, at a Reynolds number of Re = 3 million based on length "1" of the grid. The body reference area is 0.75 units. This lower wall is a curved viscous-wall bump extending from x=0 to 1.5 at the side of the computational domain y=0, but starting and ending further downstream at y locations inbetween 0 and -0.5. The maximum bump height is 0.05. The "2D" definition of the bump at the y=0 plane is:

z=0.05*(sin(pi*x/0.9-(pi/3.)))**4   for 0.3≤x≤1.2 along y=0

z=0   for 0≤x<0.3 and 1.2 <x ≤1.5

But the x-location of any position on the bump varies in the spanwise direction between y=0 and y=-0.5 according to:

x=x₀+0.3(sin(pi*y))**4   for -0.5≤y<0

where x₀ is any given x-location of the "2D" shape at y=0, and "pi"=3.1415927... The upstream and downstream farfield extends 25 units from the viscous-wall, with symmetry plane BCs imposed on the lower wall between the farfield and the solid wall. The upper boundary is a distance of z=5.0 high. It is taken to be a symmetry plane. The left and right walls are also taken to be symmetry planes. The following plots show the layout of this case, along with the boundary conditions. They are the same as given for the 3D Bump-in-channel Verification case (other than the fact that this modified bump is only half the span of the original, taking advantage of the center plane of symmetry).

Another important note: although M=0.2 is low enough that the flow is "essentially" incompressible, this is a compressible flow verification case. Therefore, if you run this case with an incompressible code, your results may be close - but not quite the same - as the grid is refined.

GRIDS
 
 

What to Expect:

RESULTS	LINK TO EQUATIONS	MRR Level
SA-neg	SA-neg eqns	4

(Other turbulence model results may be added in the future.)
 
 

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Last Updated: 01/05/2017