Learning Forum

[Ethan Johnson]

Hello!

When selecting k-omega BSL or SST models, I see that the coefficient alpha_inf is set to 0.52 -- is this a bug?

alpha_inf = 0.52 is true for the standard (Wilcox) k-omega model, and the default value for this coefficient is provided in the Fluent Theory Guide (Section 4.4.1.6 - Model Constants in Standard k-w Model).

However, when I switch the model to be BSL or SST I still see that alpha_inf is still set to 0.52, which is incorrect. Looking again at the Fluent Theory Guide, Section 4.4.2.4.2. - Product of w in Baseline (BSL) k-w Model, it provides equation 4-110 which is the correct equation for alpha_inf when using the BSL or SST model.

Just looking for a second opinion on this, maybe someone can point out what I am missing here.

Thank you!

[SRP]

Hi,

All additional model constants like alfa_infinity have the same values as for the standard k-omega model for both BSL and SST model. 4.4.3. Shear-Stress Transport (SST) k-ω Model (ansys.com)

Thank you.

[Ethan Johnson]

 

 

Thank you for the reply SRP!
Although there appears to be a communication breakdown between us. I am saying that alpha_infty is not a constant in the BSL and SST models.

Equation 4-110 in section 4.4.2.4.2 states the correct equation for alpha_infty: k-w BSL (Production of w) — It’s not a constant. In fact the line above the equation is very clear to point out this difference between the standard and SST/BSL formulations.

However I see the link that you sent clearly states that alpha_infty is a constant and its value is the same as the standard k-omega model.

 

So which is it?