Flow regime identification
 

Greetings to everyone!

Can anyone please explain me how to identify the flow regime?
For example, if I have the flow properly resolved (or precise experimental data is available), so that all characteristics of the flow are known everywhere at every timestep, how do I determine whether the flow is laminar, turbulent or transitional?

Thanks in advance,
Dmitry

If turbulent it will have a turbulence spectrum covering a wide range of time and spacial scales. A laminar flow will have only a limited range of time and space scales.

Thank You, Glenn! Could you please explain what is considered wide or limited range?

Go to your library and look at any textbook on turbulence modelling or turbulence theory. This is all basic turbulence modelling theory and should be explained in detail by any decent textbook. The text I use is "Turbulence modelling for CFD" by Wilcox, but there are many others.

Thanks again! I'll try to find some books. It has become really difficult, because foreign technical books are no longer published since USSR(

Then you should be able to find a USSR turbulence textbook. There are lots of textbooks on the topic so I bet you can find a Russian one.