Quote:
Originally posted by nerobro
has anyone considdered looking at fluid analysis programs? We could examine a circle in 2d. The turbulant wake of a boat, ball, whatever will tug at the ball a little bit. this tug is random. Like the turbulance behind a semi truck. Given that this is random, it should even out in the end. And a few pages later we see comments on the "drunken walk" sounds like a fine scientific term ;-)
It's pretty much been established that we cannot use a 2 dimensional case to examine what's happening to a spherical paintball. The results from these two cases just don't converge. A 2-D case (infinitely long cylinder moving through a fluid) results in a periodic vortex shedding, while the 3-D case results in a chaotic vortex shedding. The former results in a sinusoidal force profile acting on the object, while the latter results in a random-walk force profile.
Quote:
Originally posted by nerobro
Well, you can be sure that a shed vortex would provide a turbulant "ball" of air that the paintball will happily fall into. I would imagine the wake of a paintball would be like having a ball sit under a water faucet. If you've done the experiement where you fill a pot with water and put a ball under the flow from the faucet, the ball will stay under the faucet instead of being pushed over the edge of the pan.
Similarly, a ping pong ball will remain in a vertical column of air ejected from a vacuum cleaner running in reverse.