Boundary Layer

WhiteRaven

hi, i'm just currently doing some research on swimsuits and how they work. i have found that 1 type of swimsuit makes water "stick" to the suit longer so the water doesn't seperate and cause drag. i notice this is very similar to how golf balls work with the dimples making the air stick longer to the Boundary Layer. my question is, how does a turbulent boundary layer get the water to "stick" longer to the suit? wouldn't it be the other way around, turbulent making the water come off more quickly? also how exactly does water seperating from the boundary layer create drag? btw if there are any great websites to refer me to would be very helpful

thanks
wr

Sirus

http://scienceworld.wolfram.com/phys...daryLayer.html
http://www.mech.northwestern.edu/fac...layerflow.html
http://encyclopedia.thefreedictionar...undary%20layer

The wonders of Google

WhiteRaven

thanks, but the question still remains, why does turbulent flow make water "stick" to the boundary layer?

Clausius2

As far as I know turbulence pressurizes additionally the boundary layer against the wall. Also dynamic viscosity is virtually increased due to the turbulent stresses (turbulent viscosity). One could think of the contrary behaviour, but the external eddies enhances the more grip of the layer.

I have another question: if a turbulent layer has less drag, why do not the wings are shaped like the surface of golf balls?. I mean with those small holes on the surface.

I've tried to give you a <more humanitarian> answer than that posted a little above. I assume you have googled a bit before coming here, so that answering you with links to encyclopedias is....