Overview🔗
- Solver: simpleFoam
- 2D flow over a bump at a Reynolds number of \(3 \times 10^6\) (L=1m)
- Based on the description provided by the NASA Turbulence Modelling Resource
- $FOAM_TUTORIALS/incompressible/simpleFoam/bump2D
Mesh🔗
- 2D structured mesh created using blockMesh
-
bump described
\[y(x) = \begin{cases} 0.05 [\sin(\pi \frac{x}{0.9}-\frac{\pi}{3})]^4, & 0.3 \le x \le 1.2, \\ 0 , & 0 \le x \lt 0.3 \, \text{and} \, 1.2 \lt x \le 1.5. \end{cases}\] - this has been set in the
blockMeshDict
using acodeStream
Boundary conditions🔗
-
\(U\) based on a Mach number of 0.2. Mach number, \(Ma\), is defined as:
\[Ma = \sqrt{\gamma R T}\]where \(\gamma\) is the ratio of specific heats, \(R\) the gas constant and \(T\) the temperature. Using values for air at 300K, the inflow velocity is given as:
\[U = 0.2 Ma = 0.2 \sqrt{1.4 \times 287 \times 300} = 69.44 m/s\] -
The laminar viscosity is derived from the Reynolds number, i.e.
\[\nu_\infty = \frac{|\u| L}{Re} = \frac{69.44 \times 1}{3 \times 10^6} = 2.31 \times 10^{-5} m^2/s\]
Common fields🔗
Velocity: U
Patch | Condition | Value |
---|---|---|
Inlet | fixedValue | 69.44 m/s in x |
Outlet | zeroGradient | |
Bump | noSlip | |
Walls | symmetryPlane |
Pressure: p
Patch | Condition | Value |
---|---|---|
Inlet | zeroGradient | |
Outlet | fixedValue | 0 Pa (static) |
Bump | zeroGradient | |
Walls | symmetryPlane |
Turbulence fields🔗
- turbulence model: Spalart Allmaras
Turbulence viscosity: nut
Patch | Condition | Value |
---|---|---|
Inlet | calculated |
|
Outlet | calculated |
|
Bump | nutUSpaldingWallFunction |
|
Walls | symmetryPlane |
Spalart-Allmaras
Modified turbulence viscosity: nuTilda
Patch | Condition | Value |
---|---|---|
Inlet | fixedValue | based on \(3 \nu_\infty\) |
Outlet | zeroGradient | |
Bump | fixedValue | 0 |
Walls | symmetryPlane |
Results🔗
The NASA Turbulence Modelling Resource employs a code comparison to show that the FUN3D and CFL3D codes produce equivalent results for this case. OpenFOAM and CFL3D results are presented in the following series of images, showing that OpenFOAM results compare very favourably.