How can the coefficient in drag be determined if its a person swimming in water?
This is an excellent question. Unfortunately, the answer is almost certainly “No, there’s no easy way to calculate that coefficient.” This is because of the tremendously complicated way in which fluids flow when there’s turbulence. Note that for spheres, the answer depends critically on the fact that the spheres are embedded in laminar (not turbulent) flows. The introduction of corners (as on a square) means that turbulence appears at much lower flow rates (and higher viscosities), so that a calculation for a cube is almost never attempted. If humans swam in a fluid such as thick glycerine, where laminar flow is guaranteed at the speeds and length scales involved, then the calculation would be trivial. On the other hand, humans wouldn’t be able to get anywhere in such a fluid, because we *need* turbulence in order to break the forward/backward symmetry to get net movement. Without turbulence, a human could just move back and forth in the water, but not swim the length of a pool. Such c
