[Friendly]

Hi,

I have some question about the k-equation implementation. I have found the following source code in force kEpsilon.C:

// Turbulent kinetic energy equation                           
tmp<fvScalarMatrix> kEqn                           
(                               
fvm::ddt(alpha, rho, k_)                             
+ fvm::div(alphaRhoPhi, k_)                             
- fvm::laplacian(alpha*rho*DkEff(), k_)                            
==                               
alpha()*rho()*G                             
- fvm::SuSp((2.0/3.0)*alpha()*rho()*divU, k_)                             
- fvm::Sp(alpha()*rho()*epsilon_()/k_(), k_)                             
+ kSource()                             
+ fvOptions(alpha, rho, k_)

1.Why is there an alpha respectivly alphaRhoPhi in the equation? Does it have something to do with heat transport? I suppose is alpha is equal to 1 if heat transport is ignored. But also I exptected instead of alpharRhoPhi the mean mean velocity infront of the div(k_). Why is it missing?

2. What does SuSp and Sp mean? And why are there additional "+ kSource() + fvOptions(alpha, rho, k_)"? What do they mean?

Can anyone help?

EDIT: I just remembered that alpha might be from boussinesq. But I am still missing the meaning of alphaRhoPhi


Greetings,
Friendly

[shereez234]

Originally Posted by Friendly

Hi,

I have some question about the k-equation implementation. I have found the following source code in force kEpsilon.C:

// Turbulent kinetic energy equation                           
tmp<fvScalarMatrix> kEqn                           
(                               
fvm::ddt(alpha, rho, k_)                             
+ fvm::div(alphaRhoPhi, k_)                             
- fvm::laplacian(alpha*rho*DkEff(), k_)                            
==                               
alpha()*rho()*G                             
- fvm::SuSp((2.0/3.0)*alpha()*rho()*divU, k_)                             
- fvm::Sp(alpha()*rho()*epsilon_()/k_(), k_)                             
+ kSource()                             
+ fvOptions(alpha, rho, k_)

1.Why is there an alpha respectivly alphaRhoPhi in the equation? Does it have something to do with heat transport? I suppose is alpha is equal to 1 if heat transport is ignored. But also I exptected instead of alpharRhoPhi the mean mean velocity infront of the div(k_). Why is it missing?

2. What does SuSp and Sp mean? And why are there additional "+ kSource() + fvOptions(alpha, rho, k_)"? What do they mean?

Can anyone help?

EDIT: I just remembered that alpha might be from boussinesq. But I am still missing the meaning of alphaRhoPhi


Greetings,
Friendly

alpharhophi has rhophi which has the flux which has the velocities in it.