I'm not the guy they pay around here to do aerodynamics, so I don't have the hard numbers for you, but converting drag and other equations to compensate for things like density and scale are common in the field, and used a lot in scale tests in wind tunnels. Drag and flow issues are also dealt with extensively in submarine and ship design, which also deal with a dense media.

There is constant research into drag reduction, which in the case of submarines and ships creates greater efficiency. Even a slight reduction in drag on something like an oil tanker can save enormous amounts of fuel.

Some outfits are working on submarines that "fly" through the water.

Deep atmospheric probes might operate on the same principle as a bathyscaphe, although I suspect winds would be a serious issue.