Supersonic space shuttle

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Introduction

intro

This is an example of a steady-state compressible supersonic flow using a density-based solver.

The computational conditions are as follows

  • solver : TSLAeroFoam
  • turbulence model : $SST$ $k-omega$
  • Mach number : 3
  • Anglf of Attack : 15 degree
  • farfield pressure : 100000 Pa
  • farfield temperature : 288 K

Start BaramFlow and load mesh

Run the program and select ‘New Case’ from the launcher. In the launcher, select [Density-based] for [Solver Type].

Use the given polyMesh folder. In the top tab, click [File]-[Load Mesh]-[OpenFOAM] in that order and select the polyMesh folder.

launcher

General

Set [Operating Conditions] as 0.

Models

For this example, we’ll use $SST$ $k-omega$ model for turbulence.

Materials

Set Density as Perfect Gas, Viscosity as Sutherland.

Boundary Conditions

Set the boundary type and values as shown below.

  • spaceShuttle
    • Wall – No slip, adiabatic
  • maxy
    • symmetry
  • minx, maxx, miny, minz, maxz
    • Far-Field Riemann
    • Flow Direction : direction for AOA 15, (0.965926, 0, 0.258819)
    • Mach Number : 3
    • Static Pressure : 100000
    • Static Temperature : 288
    • Turbulence : intensity and viscosity ratio(0.1 and 1)

farfield Riemann condition

Reference Values

Set values as follows

  • Area, Length : 1
  • Density : 1.2097(farfield condition)
  • Pressure : 100000(farfield condition)
  • Velocity : 1020.5933(farfield condition)

Numerical Conditions

Set [Formulation] as [Implicit], [Flux Type] as [Roe-FDS] and [Entropy Fix Coefficient] as 0.5.

Set [Discretization Schemes] as [Second Order Upwind] for Flow and Turbulence.

Set [Convergence Criteria]-[Density] as 1e-5.

Numerical Conditions

Monitor

Select [Add]-[Forces] and set values as follows

  • Lift Direction : (-0.258819, 0, 0.965926)
  • Drag Direction : (0.965926, 0, 0.258819)
  • Boundaries : spaceShuttle

Initialization

Enter the value and click the Initialize button at the bottom. Then click the [File]-[Save] menu to save the case file.

  • Velocity : (985.817, 0, 264.149)
  • Pressure : 100000
  • Temperature : 288
  • Turbulence
    • Scale of Velocity : 1020.5933
    • Turbulent Intensity : 0.1
    • Turbulent Viscosity Ratio : 1

Run

Change the values as shown below, and click [Start Calculation] button.

  • Number of Iterations : 3000
  • Courant Number : 0.1
  • Save Interval : 500

For supersonic flows, starting with a high Courant Number often results in divergence, so starting with a small value and increasing it gradually as the calculation stabilizes can speed up convergence. During the calculation, you can modify the value in [Run Condition] and press the [Update Configuration] button in [Run] to apply it. In this example, we started with 0.1 and increased the value to 1 at around 400 iterations and then to 100 at around 700 iterations.

Residual graph

Post-processing

Click the parview button in [External tools] to open the paraview.

Change [Coloring] to p.

pressure distribution