# 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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## 2 thoughts on “BASIC kOmega-SST Boundary Conditions” Leave a comment ›

1. S.ouchene says:

L is an approximate length of the computational domain.

2. Dicky Mulyo Aditama says:

Thank you for providing this particular post for the explanation and not forget to mention this organized website. I have a question, for free stream boundary condition, what is the definition of L? is this computational length or something? is it based on paper or textbook or anything? Thank you for your attention.

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