Hi guys, first post and I hope I got the right forum. I have been doing some reading on fluid dynamics and there are a couple things I can't figure out. 1) When you light a candle or something and the smoke rises. It starts of nice and smooth, but then turns all turbulent after a little bit. What is the cause of this? 2) Golf balls. I know the dimples create a turbulent layer around the ball. This layer increase the friction drag, but it decreases the "pressure drag". I am not entirely sure how this works. I read a bunch of sites, and the best explanation i got was: http://wings.avkids.com/Book/Sports/Images/golf_01_sma.gif [Broken] ___ http://wings.avkids.com/Book/Sports/Images/golf_02_sma.gif [Broken] laminar ___________ turbulent "The larger separation region of the laminar case implies a larger pressure drag on the sphere." As I said before I am not sure how these increased separation slows the ball down. Also does laminar flow give you more control over spin and such, because ping pong balls can curve like crazy. How does this work? 3) Finally air plane wings. Again I have done a bunch of reading on this. On normal wings the "hump" is 25% of the way in, but on a laminar flow win it is 50% of the way in. This delayed hump means that the flow will be laminar for longer. If I understand correctly this means the plane will be able to go faster and have less drag. This seems to be a good thing but my research shows that laminar airfoils are only really used in highspeed jets / planes. How is this a disadvantage? EDIT: if there is better suited somewhere else please let me know.