dear sir, can we say eulerian approach is conservative form and lagrnagian approach as non conservative form?

No - an Eulerian approach can be non-conservative or conservative. A conservative approach involves casting the flux terms as a divergence of a flux function.

ya any approach can be converted into conservative or non conservative forms..we can do this using mathematical formulations like using advection terms.but can anybody explain the physics going behind that? like how by just changing into divergence form,u can assure conservative?

Thanks in advance,

Deepak

The differential equations that we normally solve are actually derived from integral equations that hold globally. When they are reduced to differential form then the equations hold locally and we need extra conditions to ensure global conservation. The divergence form is one form that can be directly related to the integral form of the equations via Gauss' Divergence theorem. It thus possesses better conservation properties than a non-conservative scheme (for example the ability to capture shocks without the explicit application of the Rankine-Hugoniot condition). At least, that's how I learned it. More information could be found in the Wiki article, as well as googling for conservation form+CFD. Most textbooks also include some information on this.