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July 5, 2022, 08:19 |
Adding an implicit gradient term
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#1 |
Member
Uttam
Join Date: May 2020
Location: Southampton, United Kingdom
Posts: 34
Rep Power: 5 |
Dear FOAMers,
I have a question regarding the implicit gradient. Here is my system of equations that I wish to solve Screenshot from 2022-07-05 17-42-49.png I have the solve for u^dagger and the quantity \Tilde{u} is known. I am doing this using a modified SIMPLE algorithm (by playing around with the simpleFoam solver). Here is the code that I have implemented Code:
fvVectorMatrix UEqn ( //Laplacian term 4th term from left on the L.H.S of the equation 1 - (fvm::laplacian(nu,UDagger)) //1st term from left on the L.H.S. of the equation 1 - fvm::div(phi, UDagger) + fvm::SuSp(fvc::div(phi), UDagger) //2nd term from left on the L.H.S of the equation 1 + (UDagger & T(fvc::grad(U1))) ); Screenshot from 2022-07-05 17-47-42.png to be treated implicitly or explicitly? If it has to be treated implicity, how do I make a conversion just the way I did for the second term in fvVectorMatrix?
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Best Regards Uttam ----------------------------------------------------------------- “When everything seem to be going against you, remember that the airplane takes off against the wind, not with it.” – Henry Ford. |
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July 5, 2022, 10:37 |
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#2 | |
Senior Member
Santiago Lopez Castano
Join Date: Nov 2012
Posts: 354
Rep Power: 15 |
Quote:
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July 5, 2022, 10:42 |
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#3 | |
Member
Uttam
Join Date: May 2020
Location: Southampton, United Kingdom
Posts: 34
Rep Power: 5 |
Quote:
But please help me understand this a little better. The term is u.grad(udagger)^T How is this converted into div(U*U)? I would have to use fvm::div(flux, unknown) in that case but I am not sure if that is equivalent to the term u.grad(udagger)^T What do you think?
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Best Regards Uttam ----------------------------------------------------------------- “When everything seem to be going against you, remember that the airplane takes off against the wind, not with it.” – Henry Ford. |
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