CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   Main CFD Forum (http://www.cfd-online.com/Forums/main/)
-   -   Wanted buoyancy constants in k-epsilon model (http://www.cfd-online.com/Forums/main/1791-wanted-buoyancy-constants-k-epsilon-model.html)

grig February 4, 2000 05:50

Wanted buoyancy constants in k-epsilon model
 
Generation of turbulence due to buoyancy sometimes is included in k-e model "... +c1(eps/k)(1-c3) g mu / (rho sigma _ h) * d rho/d z +... ", where c1=1.44, g=9.8, etc. Please who can tell typical (Mach=0) values two constants c3, sigma_h and appropriate references?

Thank you. Grigory.

Jens Wyrwa February 5, 2000 19:21

Re: Wanted buoyancy constants in k-epsilon model
 
As far as I understood, you address the C3 empirical constant, that appears in the epsilon equation of k-epsilon turbulence model. C3 is connected with the buoyancy influence on turbulence. (your formula-fragment does not match with formulations I know)

Rodi (Turbulence Models and Their Application in Hydraulics 1980) discusses it and suggests a value of 0.8 connected wich an appropriate formulation of flux Richardson number. Recent investigations I read about (Sanders et al. Int. J. Heat Mass Transfer No.4(1997), Char+Hsu Int. J. Heat Mass Transfer No.12(1998), Hwang+Chiang J. Fluids Eng. Dec.1995 ), leave it out or set it to zero.

I need to find out about this problem myself. So if somebody in this forum knows more, please be so kind to send a note.

Jens Wyrwa


All times are GMT -4. The time now is 11:25.