# BASIC kOmega-SST Boundary Conditions

## kω-SST (komegaSST) Boundary Conditions

Here the basic boundary conditions if you are using the kOmegaSST model in OpenFOAM:

At the wall:

• ω (omega) – specific dissipation rate
• BC type: fixedValue
• BC value: $\omega_{wall}=10\frac{6\nu_\infty}{\beta_1\left(\Delta y_{wall}\right)^2}$

Note: The omegaWallFunction actually calculates this BC value for omega at the wall. Therefore, you can use it, even if you aren’t using wall-functions. It just applies the correct value for omega at the wall.

• k – turbulent kinetic energy
• BC type: fixedValue
• BC value: 0
• nut – turbulent viscosity
• BC type: fixedValue
• BC value: 0

In the free-stream:

• ω (omega) – specific dissipation rate
• BC type: fixedValue
• BC value: $\frac{U_\infty}{L} < \omega_{\infty} < \frac{10 U_\infty}{L}$
• k – turbulent kinetic energy
• BC type: fixedValue
• BC value:$\frac{10^{-5}U_\infty^2}{Re_L} < k_{\infty} < \frac{0.1U_\infty^2}{Re_L}$
• nut – turbulent viscosity
• BC type: calculated
• BC value: 0 (this is just an initial value)

where $\beta_1=0.075$, and $\Delta y_{wall}$ is the normal distance from the wall to the first cell center.

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CFD

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