|March 19, 2016, 10:32||
Join Date: Mar 2016
Posts: 6Rep Power: 2
I'm trying to model the drag coefficient on a car.
When i set the Turbulence Intensity to 15% at the inlet and outlet backflow and plot the result, I can see that the turbulence intensity immediatly drops to basically 0% right after the inlet (so it has no influence).
The turbulence viscosity ratio is 10 and I use a uniform velocity profile (25m/s horizontal at inlet).
How do I solve this?
|March 25, 2016, 14:21||
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 1,372Rep Power: 20
A uniform velocity profile is shear free and therefore has limited capability to produce and sustain turbulence. Thus any turbulence at the inlet will eventually decay and die out (reach 0%). The question is how long of a distance until it decays and this depends on the length scale of the turbulence.
A turbulence viscosity ratio of 10 is extremely (pathetically) mild. This magnitude of the viscosity ratio is what you would expect to see at the edge of a boundary layer (the freestream boundary, where the shear is very small and very little turbulence exists).
|Thread||Thread Starter||Forum||Replies||Last Post|
|Turbulence Intensity at inlet boudary||egge24||FLUENT||1||October 10, 2015 15:56|
|Turbulence intensity - cross wind on a body||Fabio88||Main CFD Forum||0||May 4, 2015 03:44|
|How to define the turbulence intensity and mixing length at an outlet (for k-eps)?||david39||OpenFOAM Running, Solving & CFD||6||February 2, 2011 04:01|
|High turbulence intensity||wenfengxie||FLUENT||1||April 16, 2010 12:00|
|High Turbulence Intensity Problem||bwg||FLUENT||1||January 13, 2010 14:09|