Determining Flow Type: Turbulent or Laminar?

[semc]

Hey guys how do you know when will a flow be turbulent or laminar?i came across a question asking what's the flow of the wind on the sail of a sailboat.i thought that since there is the sail to block the wind when the boat is surfing against the wind, the flow will be turbulent but the ans is laminar flow any help on how to determine the flow?

 

[Astronuc]

Usually one uses Reynold's number with appropriate characteristic data to determine if the flow is laminar or turbulent.

If the flow was turbulent, the flow would not form a pressure differential across the sail. Aircraft wings/foils require laminar flow to generate lift. If the flow was turbulent, the low pressure area would not be stable.

This might be of interest - http://www.grc.nasa.gov/WWW/K-12/airplane/shortc.html

Also -
http://www.grc.nasa.gov/WWW/K-12/airplane/

http://history.nasa.gov/SP-367/contents.htm

 

[semc]

wow thanks man the links are great!really wonder where i got the stupid idea that the flow above the aerofoil is turbulent...haha