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 Excom April 28, 2009 07:56

Finite Difference - Nonuniform mesh

Hi

I am trying to solve Poissons equation with the use of the finite difference method.

Is there any one that can tell me how the second order derivative lookes like in the interface between a fine and a rough mesh?

I know that this has nothing to do with fluid dynamics, but maybe some one is familiar the finite difference method and is able to help me.

 harishg April 28, 2009 09:21

You can get the finite difference formula for non uniform mesh by writing the derivative as
f_primeprime = a f_i-1+ b f_i + c f_i-1
Expand the RHS using Taylor's series and match the coefficients on both sides to get a,b anc c.

 CFDstudent May 11, 2009 18:08

finite difference approximation to 2nd derivative