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amirmohammad January 8, 2014 07:42

Convergence
 
hi,
I have a question...
how can I converge an equation with just a convection term?
I don't have any diffusion and unsteady and source terms...
does it have any specific discretization? :(

laingmj January 8, 2014 09:27

More detail
 
Can you describe in more detail what it is that you are trying to do?

amirmohammad January 8, 2014 12:17

Quote:

Originally Posted by laingmj (Post 469138)
Can you describe in more detail what it is that you are trying to do?

I use a finite volume code, in the species equation with the simplification I just have a convection term and it is equal to zero.
In this situation my code is running to diverge.

FMDenaro January 8, 2014 12:49

Quote:

Originally Posted by amirmohammad (Post 469157)
I use a finite volume code, in the species equation with the simplification I just have a convection term and it is equal to zero.
In this situation my code is running to diverge.


Is that something like Div (rho*V) =0 ? that is a constraint, must be satisfied coupling it to the other equations.

amirmohammad January 8, 2014 12:57

Quote:

Originally Posted by FMDenaro (Post 469162)
Is that something like Div (rho*V) =0 ? that is a constraint, must be satisfied coupling it to the other equations.

It is Div (rho*U*C)=0.0

C is the concentration of species.

FMDenaro January 8, 2014 13:02

the key is the same, the convergence of the solution is obtained while solving a system of equations, you can not focus only on this single equation

amirmohammad January 8, 2014 13:05

Quote:

Originally Posted by FMDenaro (Post 469166)
the key is the same, the convergence of the solution is obtained while solving a system of equations, you can not focus only on this single equation

I have 5 equations

1) u momentum
2) v momentum
3) pressure correction
4) oxygen concentration
5) water concentration

in water concentration I just have a convection term as follow:
Div ( rho*U*C) = 0.0


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