Hi FOAMers, I would like to
 

Hi FOAMers,

I would like to have your opinion about the following problem:

- the strain tensor is defined as


- and, according to the linear algebra, its magnitude is


- now, if I let OpenFOAM to write out both the U gradients and S


I see that values coming from (3) and (2) (calculated manually) are different.

I had a look to the vectorSpace class and what I can understand (with my little C++ knowledge), is that the magnitude of a tensor S is given by


which differs from Eq. (2). Additionally, a manual check with the help of Eq.(4) does not return what is given by OF (Eq. (3)) and there is not any constant factor between their values...

What am I missing?

Thanks a lot,
Massimiliano

Hello Foamer,

strain rate Tensor is defined by

S:=1/2 [ grad(U)+gard(U)^T]

Try it and give me respond if it's worked.

Cheers