CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   Fluent UDF and Scheme Programming (http://www.cfd-online.com/Forums/fluent-udf/)
-   -   Any idea on how to obtain Yplus value for interior cells? (http://www.cfd-online.com/Forums/fluent-udf/99758-any-idea-how-obtain-yplus-value-interior-cells.html)

 g0800276 April 11, 2012 02:00

Any idea on how to obtain Yplus value for interior cells?

Although C_Wall_Dist can calculate the distance between a cell and the nearest wall, we could not identify this wall and thus can not get the wall shear stress, which is required for the calculation of Yplus.

I have searched, through the entire google, for this problem without a solution. Do you have any idea to share with us?

Regards,
Joshua Zhu

 Ati_CFD August 18, 2013 09:18

calculation of y+ for interior points?

Quote:
 Originally Posted by g0800276 (Post 354108) Although C_Wall_Dist can calculate the distance between a cell and the nearest wall, we could not identify this wall and thus can not get the wall shear stress, which is required for the calculation of Yplus. I have searched, through the entire google, for this problem without a solution. Do you have any idea to share with us? Regards, Joshua Zhu
Quote:
 Originally Posted by om3ro (Post 251529) I'm trying to implement the Chien model with OpenFoam, but I have some general doubts on the description of y+. The Chien model uses y+ for the definition of the damping factors. Suppose to describe a 2D duct flow in with the following configuration: HTML Code: ```
/\  y       |       |       |       ------------>  x  ____________________________________________ ->                                                                    -> ->                                                                    -> ->                                                     *             -> ->_________            _ ,    °   .________,*________->                   |         |  |         |                                   |____ _|  |___ __|
``` y+ is defined as: y+ = (U_t * y) / nu and U_t(x) = sqrt(tau_w(x) / rho) y+, U_t, tau_w are functions of x!!! It is necessary to define for each point (x,y) of the numerical domain the x coordinate in which define y+, U_t and tau_w. An example: In both points identified with " * ", tau_w must be evaluated in " , ". But in the point " ° ", shall tau_w be associated with " , " or with " . " ? Does anybody have experience on this aspect? What is the principle to adopt in this task? Marco

Hi,
The Chien model uses y+ for the definition of the damping functions.
Does anybody have knowledge about calculation of y+ for interior points?

Best Regards,
AtiCFD

 All times are GMT -4. The time now is 11:36.