Quote:
Originally Posted by ConnClark
Ummmmm.... this isn't how it works.
Golfball dimples mix are used to mix the faster moving air with the slower moving air of the boundary layer thus thinning it and maintaining dynamic pressure which allows it to follow the corners and bends in the body. A thicker boundary layer tends to form turbulence and thus is more prone to separation and hence more drag.
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I am still getting my head around this and the fact that laminar flow and boundary layers are just mathematical constructs, assume you are talking in a relative sense, as it is the golf ball that moves through stationary air, but either way one assumes a measure for the limit of the boundary layer, 95 - 99.99% of free stream velocity depending on source, so if you mix the stationary air at the balls surface with the moving air further away, the mixed air is has a lower velocity than the free stream and is the boundary layer.
You can't mix stationary air with fast air and expect it move at free stream velocity, any air below that velocity is part of the boundary layer.
With the dimpled golf ball compared to a smooth ball, the smooth ball has less skin friction on the face, and has a more laminar flow, but seperation occurs immediately after the equator and has a much larger wake, where as the dimpled ball has greater skin friction on the face because of the increased turbulence, but this increased turbulence (boundary layer) results in higher pressures on it's surface which result in delayed seperation and a smaller wake and lower drag which allows it to maintain a greater velocity for longer.