[courtjester140]

Hello,
I'm about to start a new project, taking a look at flow passing over a flat plate that has channels cut into the surface. The channels will be pretty shallow, say .00025 inches, and only about .015 inches wide, spanning the entire plate (which as far as I am concerned is infinity at this point).

I'm afraid of using typical theory here because of the small size of the channels. Is there a cutoff where microfluidics theory should be used? Is there an in-between macro and micro that I can use here?

My goal is to write a quick bit of code to analyize how the channels affect pressure and the boundary layer. This will be incompressible viscous flow.

As a bonus, i'd like to incorporate surface roughness in the channels, say ranging from 32-200 Ra. What tools do I have at my disposal to look at surface finish effects on flow from a purely analytical standpoint?

Thanks!