Constitutive Relations
 

Hi all

Does anybody know of groups/people researching constitutive relations in fluid mechanics ? Are the presently accepted constitutive relations being questioned ? Is there any basis for somebody to question these ?

TIA

Regards,

Eddy

Re: Constitutive Relations
 

I have once been told that Stokes' hypothesis,

mu' = lambda + 2/3 mu

has never been verified experimentally.

Is that true? Does anybody have any info on that?

The bulk viscosity mu' is 'assumed' to be zero. (See Schlichting, Boundary Layer Theory, 7th Edition, p.61-63)

Re: Constitutive Relations
 

There is an extensive literature on constitutive relations, you just have to do a proper literature search. Information on bulk viscosity is hard to find, but there are little bits and pieces in some of the standard books, such as "Compressible-Fluid Dynamics" by P. A. Thompson, pages 30 and 111. The bulk viscosity is zero only for low-density monatomic gases.