Turbulence Intensity vs Reynolds number
 

Hi everyone
I don't have too much background in fluid dynamics. From ANSYS user manual, turbulence intensity (I) of fully developed pipe flow is defined as :

I=0.16 *Re_dh^-1/8.

where Re_dh is the Reynolds number. It seems that turbulence intensity is inverse proportional to Reynolds number. We know that Reynolds number of laminar flow is much smaller than that of turbulent flow. But according to this equation, does that mean turbulence intensity of laminar flow is higher than that of turbulent flow? This doesn't make any sense because laminar flow should shouldn't have turbulence intensity or very low turbulence intensity. Which part I didn't understand correctly? Thanks.

I don't think that this formula is thought to be applicated for creeping flow or Re just beyond it.

In turbulent cases you have an effect: With lower Re the eddies take more room, because there is more time for expansion. An example is a well devloped Kármán vortex street. At much higher values of Re the turbulent area gets much more norrw, but with vortices containing more energy. A missile does't give a wide vortex street.

Thats the way I explain for me what the formula contains.

Thanks Uwe.

hello every one.
I have a question about the flow regime, according to my bibliographic research I found that for low numbers of Reynolds i.e: 600- 1400,
The k-e turbulence model is introduced into the calculation, but the regime is laminar, can you please answer me.