I cannot imagine a two-phase mixture of liquid copper and water, so the physics of that model questionable. Hence, you do need to consider copper as a colloid or nanoparticle and the mixture as a "suspension". I doubt that this kind of system is well understood but you might look at recent papers on Brownian suspensions, such as those by J. Brady et al.

To add to Joe's comment. In modeling to extract coarse-grained Eulerian mixture models (as Joe mentioned), you do need to treat the copper particles as discrete entities, though they probably are too small (without aggregation which would give you even more complications) to be well represented by closure models used in the granular community. Some methods to do this could include simulation methods like Stokesian dynamics, but may also require explicit representation of the solvent if particle dimensions are far below the micron scale as in a nanofluid. Not fully aware of this literature, myself, but searching it is probably your best bet.

Thanks a lot Joe Goddard and Eric Murphy sir for the reply,

Completely agree to your statement Joe Goddard sir, but if we consider the secondary phase as granular and enter a diameter of 100nm will it not represent the same physics.

Silts, sands, gravel, boulders, and planets all obey the physics of classical/relativistic mechanics. BUT the "physics" at each scale differs quite a bit based on the scale and essential nature (important mathematical terms) of the problem. To answer your question directly - compute a Peclet number as given in J. Brady's 2009 Physics today for your problem. Then compute it for 1 mm sand sheared at 10 s^-1 in air (or water for that matter). And finally, consider the consequences/read the literature/talk to your adviser or boss.

Thanks a lot Eric Murphy Sir.