CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   Main CFD Forum (http://www.cfd-online.com/Forums/main/)
-   -   Help with calculating turbulence parameters! (http://www.cfd-online.com/Forums/main/83949-help-calculating-turbulence-parameters.html)

Dan Chambers January 16, 2011 16:02

Help with calculating turbulence parameters!
 
Evening all,

I'm trying to calculate the boundary turbulence parameters for a case. I am modelling a flat plate (0.76m x 0.406m) with two strakes on to generate vortices.

From experimental data I know the turbulence intensity is 2% and I have set the turbulent length scale to be 7% of the plate width (0.028m). I have also assumed in the calcs below that the mean flow velocity is the freestream value of 53.6m/s (not sure if this is correct or not).

Using the calculation in the fluent manual (http://combust.hit.edu.cn:8080/fluen....htm#ke-params) I find the following values:

Turbulent kinetic energy: 1.723776
Turbulent viscosity ratio: 1354.598
Dissipation Rate: 13.08516

From this I'm pretty sure I'm doing something wrong as I was expecting the turbulent viscosity ratio to be below 10!

Can anyone please offer me some advice on this as I'm completely at a loss as to what I've assumed wrong to make the calculations give such wrong numbers. Any help is very much appreciated.

Many thanks
Dan


All times are GMT -4. The time now is 14:10.