I am interested in the viscous drag of a floating body (let's say an cylindrical iceberg in water) moving with a constant velocity, s.t. the Reynolds number of the fluid is very large. I am taking a course in continuum dynamics and I am able to write down the equations of the fluid and the corresponding boundary conditions (I also got some prior knowlegde in Perturbation theory and PDEs). I am well aware that determining a drag coefficient for some flow with an awful geometry is nearly impossible. I know that even for fully immersed cylinders this drag coefficent cannot be determined analytically as function of the Reynolds number.
My question is now: what methods/estimates can one use to say something meaningful about the drag on such a floating body for a stationary flow of high reynolds number? Is there a possibility to do apply boundary layer theory in some way to get some crude estimate for a drag coefficient? I am not very familiar with the art of estimating.
By the way, I want to refrain myself from solving the PDEs numerically, since I am just looking for a very (very!) crude estimate.
I hope that you guys could help me to find a place to start.
I thank you in advance!