Michael Rembe
Certified Consultant
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Posted:
6 years ago
Feb 14, 2019, 10:04 a.m. EST
Hi Hao,
the two equation turbulence models of COMSOL provide wall functions for rough walls. You can find it in the COMSOL documentation (for example: Theory for the Turbulent Flow Interfaces -> The k-ε Turbulence Model).
Best regards
Michael
-------------------
Michael Rembe
Rembe Consulting PartG mbB
www.rembe-consulting.de
Hi Hao,
the two equation turbulence models of COMSOL provide wall functions for rough walls. You can find it in the COMSOL documentation (for example: Theory for the Turbulent Flow Interfaces -> The k-ε Turbulence Model).
Best regards
Michael
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Posted:
5 years ago
Feb 15, 2019, 2:55 a.m. EST
Updated:
5 years ago
Feb 15, 2019, 2:55 a.m. EST
Hi Hao,
the two equation turbulence models of COMSOL provide wall functions for rough walls. You can find it in the COMSOL documentation (for example: Theory for the Turbulent Flow Interfaces -> The k-ε Turbulence Model).
Best regards
Michael
Thanks very much Michael.
>Hi Hao,
>
>the two equation turbulence models of COMSOL provide wall functions for rough walls. You can find it in the COMSOL documentation (for example: Theory for the Turbulent Flow Interfaces -> The k-ε Turbulence Model).
>
>Best regards
>
>Michael
Thanks very much Michael.
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Posted:
5 years ago
May 31, 2019, 11:31 a.m. EDT
Updated:
5 years ago
May 31, 2019, 11:32 a.m. EDT
Hello All,
Sorry to revive the topic after it appears to have been resolved, but I have a similar lack of understanding.
I'm attempting to implement a given roughness height
in my k-
turbulent flow models of hydrazine and xenon.
I've read through the documentation and it sounds like there should be a location in the standard COMSOL GUI to insert or modify the value of
to account for varying wall roughnesses---the documentation specifies that modifying
and
is the appropriate way to adjust for different sand roughness heights.
I cannot seem to find a means to insert the appropriate node under the Wall boundary condition, or introduce an appropriate choice in the turbulent model settings, such that the roughness height is available for me to modify. The back-end equations view shows no such value
or
in the Wall node.
Is there a way to activate
such that I can easily modify it, or are we supposed to manually modify the friction roughness equation
according to the theory provided in Theory for the Turbulent Flow Interfaces -> The k-ε Turbulence Model?
I appreciate your time, thank you!
Hello All,
Sorry to revive the topic after it appears to have been resolved, but I have a similar lack of understanding.
I'm attempting to implement a given roughness height k_s in my k-\epsilon turbulent flow models of hydrazine and xenon.
I've read through the documentation and it *sounds* like there should be a location in the standard COMSOL GUI to insert or modify the value of k_s to account for varying wall roughnesses---the documentation specifies that modifying C_s and k_s is the appropriate way to adjust for different sand roughness heights.
I cannot seem to find a means to insert the appropriate node under the Wall boundary condition, or introduce an appropriate choice in the turbulent model settings, such that the roughness height is available for me to modify. The back-end equations view shows no such value k_s or C_s in the Wall node.
Is there a way to activate k_s such that I can easily modify it, or are we supposed to manually modify the friction roughness equation u_\tau according to the theory provided in Theory for the Turbulent Flow Interfaces -> The k-ε Turbulence Model?
I appreciate your time, thank you!