Streamline or turbulent flow?

  1. Hey guys how do you know when will a flow be turbulent or laminar?i came across a question asking whats 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 :confused: any help on how to determine the flow?
     
  2. jcsd
  3. Astronuc

    Staff: Mentor

    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
     
    Last edited: Sep 30, 2006
  4. wow thx man the links are great!really wonder where i got the stupid idea that the flow above the aerofoil is turbulent...haha
     
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