hello friends, I understood how the basic 3 governing eqns can be obtained in conservative and non conservative form. but i got a question that why the eqns have to be obtained in these forms? plz reply

Eqs in conservative and non conservative forms are mathematically equivalents. The point is that some numerical methods such as Finite Volume types are developed based on the conservative form. In this way, these numerical algorithms force the conservation of the total flux. Other methods such as Finite Difference types consist in getting an approximation of the equation independent of the form.

In general, independent of the numerical method and form of the equation you should get the same solution.

FVM are based on conservative form you said. why not non conservative???????

Dear Vijesh..

In Finite Volume Method we are integrating the Gov. equations for each CV throughout the domain. So it directly utilizes the conservation. In Finite Difference we have to confirm the conservation. I mean we have to prove there is no loss and No gain of any of mass, mom and energy.

In finite Volume Method, At interface, flux coming from left CV is equal to going to Right CV.in the same way top and bottom . so fluxes at each CV cancel each other. Finally it arises the Only Boundary conditions and whole domain acts as a single CV.

I hope it will help Regards Mohammed

Thank you Mohamed.

[einstein_zee]

Since the answers are vague I just wanted to add a short read for the original question : computational methods for fluid dynamics, Ferziger & Peric, page 7-9 shortly explains the story behind conservative and non-conservative forms... hope it helps