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 MJK April 6, 2003 16:12

Entropy calculation using CFD

Hello there,

I am looking for a way to calculate sum of entropy rises due to viscous effects, shoks, temp. gradient etc. throughout the computational domain and compare it with entropy difference of outlet and inlet.

I wonder if anyone can help or introduce a reference.

Appreciated

MJK

 walter schwarz April 8, 2003 08:45

Re: Entropy calculation using CFD

 MJK April 8, 2003 10:46

Re: Entropy calculation using CFD

Thanks Walter,

In fact that was the only source I had found on this matter- of course other than what Bejan has explained in his text.

I wonder if anyone has tried such an approach and been able to match entropy generation due to viscous dissipation and temp gradient WITH the overall entropy rise throughout the domain.

Regards

MJK

 Bob Roach May 8, 2003 05:50

Re: Entropy calculation using CFD

Entropy is a state variable, as such it may be computed from two other state variables (like pressure and temperature). Why can you just not compute it at each of your points in the domain.

 Mkermani@unb.ca May 11, 2003 16:44

Re: Entropy calculation using CFD

Bob,

That is right- entropy at any point can be obtained in terms of two other independent variables.

I was asking how is it possible to obatin and compare entropy generation within the domain due to (1) viscous effects, (2) thermal effects and (3) shock waves.

Some good explanation is given in text by A Bejan- but it does say no wrod about the shock effect.

Regards