Resistive forces on a submarine?

[K_Factor]

Lets say I was going to build a submarine, how could I determine most accurately the resistive forces as it is traveling in sea water at a constant velocity. I need to know how much energy it would consume per km. Cant find anything about this online..

Thanks in advance!

 

[mgb_phys]

You would probably determine the frcition forces from the amount of energy (or rather power) it used at constant speed.

If you were developing a submarine you would do CFD modelling in a computer or drag a model behind a boat with a force gauge - depending on how big a navy you are.