Considering the flow through a dense net / grid
 

I have a grid like structure in the flow path and I'd like to consider it's effect with out actually meshing it.

The attached image shows the sructure / surface im talking about.

I'd like just keep it as a plane surface with out actually meshing those small holes but considering their effect by some means.

Could some one please tell me how to do this.

Hi saisanthoshm88,
in the past I worked on a burner with a very dense metallic net: I modelized it with porous zone, so I suggest using it (even porous jump can be used).
See Fluent Manual for info about it (if you'll have some specific question maybe I''be able to answer ;))

Regards

Yaa I think the porus jump boundary condition could be used here but I didn't know how to calculate the face permeabilty and pressure jump coefficient to my case.

I don't know the velocity of flow through this perforated plate it's just lying in the flow path.

Could some one please suggest on this

Perhaps you can find some empirical correlations about velocity and pressure through a grid like yours...
Or you could model a small fraction of the system (maybe taking advantage of symmetries) and simulate it with a good mesh even for the holes :)