Mach 2.0, 15 Degree Wedge

Figure 1. Pressure contours of the Mach 2.0 15 degree wedge

Introduction

Mach 2.0 flow over a 15 degree wedge was used to test the Wind code's ability to compute supersonic inviscid flows and in particular to capture shock waves.

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Grid

Figure 2. 2D view of the grid

Figure 3. 3D view of the grid

The unstructured grid was generated using GridGen. The shock position was computed using inviscid theory and grid points were clustered around this line. The grid was developed as a two-dimensional plane and then extruded to three dimensions for Wind-US. The grid consists of 4,884 points.

After the cgd file was exported from Gridgen, CFPART was used to add lines to the grid in preparation to be solved with Wind-US3.146. In Table 1, both the Common and Gridgen versions of the grid are attached as well as the CFPART script used to add lines.

Freestream Conditions

Boundary Conditions

Figure 4. Boundary conditions. Note: This is a 2D view of the 3D grid. Inviscid walls were specified on the sidewalls/xy-planes.

Computation Strategy

Monitoring the residuals was used to determine the convergence of this case. Below are the algorithm settings established in the dat file.

Input Parameters and Files

Computation

The same numerical scheme, RHS HLLE SECOND, was used for all the wedge test cases run with Wind-US 3.146.

Post-processing

Post-processing for this case was done with a simple bin script that can calculate skin friction, velocity, or residuals. Only residuals were calculated with this script. A CFPOST script was also used to determine the centerline pressures where the shock occurs. Since CFPOST cannot be used to generate PLOT3D files, the cgd and cfl files can be loaded into Tecplot using the Common File Format Loader. Pressures can then be measured using the "Probe" tool. "Analyze>Calculate" can be used to calculate more variables and "Data>Alter" can be used to rescale data.

Results

Figure 5. Mach contours of the wedge

Figure 6. Centerline pressure at the shock

Figure 7. Residual plot used for determining convergence

Contact Information

This validation test case was performed by Keven Lenahan. Contact: Manan Vyas, (216) 433-6053. MS 5-12, NASA Glenn Research Center, 21000 Brook Park Road, Cleveland, Ohio, 44135.