Help with Length Scale estimation/perforated plate
 

Hi! I am a beginner, and I need some help with length scales. What exactly are length scales? I saw an equation of l=0.07L. What is l? Also for a perforated plate, is L the thickness of the plate? What I understand is that downstream of the perforated plate I need to have cells of length around 7% of the thickness of the plate. Is this correct?

Re: Help with Length Scale estimation/perforated p
 

Please this is urgent. I cannot believe nobody knows anything about length scales?!?!

Re: Help with Length Scale estimation/perforated p
 

l is the turbulence length scale, related to the size of the large eddies in a turbulent flow.

For a fully developed duct flow, l is restricted by the duct size, L, typically, the hydraulic diameter.

Re: Help with Length Scale estimation/perforated p
 

Thanks Do you know anything about an obstruction in the flow like a perforated plate, what L would be in that case?