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fvm::div(T) or fvc::div(T)

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Old   October 11, 2013, 22:12
Default fvm::div(T) or fvc::div(T)
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Dongyue Li
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Hi guys,

I wanna make a discretisation on a turbulence stress tensor.\nabla \cdot \tau

In this term. \tau  = scale\left( {nut,\nabla U} \right)

In most of the situation, nut is a scalar. After discretisation, you can get:
\nabla  \cdot \tau  = \nabla  \cdot \left( {nut\left( {scalar} \right)\nabla U} \right) = fvm::laplacian\left( {nut,U} \right)

But in my case, nut is a turbulence tensor. So I cant turn it into laplacian term.I have to use fvc::div as follows:
\nabla  \cdot \tau  = \nabla  \cdot \left( {scale\left( {nut\left( {tensor} \right),\nabla U} \right)} \right) = fvc::div\left( {scale\left( {nut,\nabla U} \right)} \right)

But actually, I wanna discretize the term into the matrix equation. But I cant use fvm::div(). What should I do.? Thanks.
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Old   October 11, 2013, 22:18
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BTW.
scaling vector a by vector b would produce vector c whose components are
ci = scale(a, b) = (a1b1, a2b2, a3b3)
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Old   October 13, 2013, 19:51
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Any ideas?
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Old   October 13, 2013, 20:12
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Dongyue Li
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Am I clear on this topic?
I mean lets say I have a scalar "a" and a tensor "T". So this formula \nabla  \cdot \left( {a\nabla U} \right) in code is:
Code:
fvm::laplacian(a,u);
Regarding this formula:\nabla \cdot  \left( {T} \right)in code is:
Code:
fvc::div(U);
But I want it to be Imp. What should I do?
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