Langley Research Center Turbulence Modeling Resource

3D Bump-in-channel Verification Case - Intro Page

The purpose here is to provide a large sequence of nested grids of the same family, along with results from existing CFD codes that employ specific forms of particular turbulence models, in order to help programmers verify their implementations of these same models. On a given grid, there may be differences between the results from different codes, but presumably as the grid is refined the results should approach the same answer (if the flow conditions and boundary conditions are the same). With verification, the purpose is not to establish the "goodness" of a model compared to experiment, but rather to establish that a model has been implemented correctly, as intended according to the equations and boundary conditions. (It is through validation that a model's "goodness" is established.) The purpose here is primarily verification.

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 essentially incompressible conditions: M = 0.2, at a Reynolds number of Re = 3 million based on length "1" of the grid. The lower wall is a curved viscous-wall bump extending from x=0 to 1.5 at the two sides of the computational domain y=0 and y=-1, but starting and ending further downstream at y locations inbetween. 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