Decay of turbulence through the domain
 

Hi everyone,
I am trying to investigate the effect of differing levels of turbulence on an aerofoil, by setting the turbulence intensity at the inlet to 10%, 1% or 0.1%. Unfortunately as I refine the mesh, the turbulence decay becomes significant and so after only one or two chord lengths after the inlet, the TI has reduced to well below 0.1% regardless of the particular inlet condition.

I'm using 2D DES with k-w SST for the near wall region.

Does anyone have any suggestions on either how to sustain the turbulence throughout the mesh, or perhaps to 'create' turbulence in the region upstream of the aerofoil, without the necessity to model and resolve baffles/walls to physically disturb the flow.

Many thanks,

Gareth