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Having troubles in understanding the correction term in pressure equation

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Old   January 25, 2012, 18:37
Default Having troubles in understanding the correction term in pressure equation
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Kai
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Hi,

I have troubles in understanding the correction term in pressure equation.
For example in buoyantPimpleFoam,
Code:
        
fvScalarMatrix p_rghDDtEqn
(
    fvc::ddt(rho) + psi*correction(fvm::ddt(p_rgh))
  + fvc::div(phi)
);
where does the term psi*correction(fvm::ddt(p_rgh)) come from?
It seems like it origins from the difference between old value and current value of rho. But how about if we write the eqn as
Code:
        
fvScalarMatrix p_rghDDtEqn
(
    fvc::ddt(psi,p) 
  + fvc::div(phi)
);
Back to the correction part, why there is no term like
Code:
        
 p_rgh*correction(fvc::ddt(psi))
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Old   October 8, 2012, 05:19
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pengfei han
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Have you solved it?
I'm confused too. It should be related to the material differential of pressure, but I don't know how to get it in this particular form.
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