force needed to overcome water drag

[dl09]

how do i calculate the force needed to overcome the friction between a submarine and the water?

 

[Slay the P.E.]

how do i calculate the force needed to overcome the friction between a submarine and the water?

If it’s for the PE exam, perhaps you can model it as a flat plate (or two plates) and use the correlations for the drag coefficient. Then from there you can get the drag force.

 

[dl09]

Could you model the submarine as a sphere and get accurate values?

 

[Slay the P.E.]

Could you model the submarine as a sphere and get accurate values?

If it’s for the PE exam (the focus of these boards) then a sphere would be a bad idea simply because the correlation for drag on a sphere is not in the reference handbook (I think)

Also, we’re getting into “spherical cow in a vacuum” territory: Spherical cow - Wikipedia

 

[Slay the P.E.]

.