CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   Reynolds for a rotary wing/blade (http://www.cfd-online.com/Forums/cfx/95296-reynolds-rotary-wing-blade.html)

mohammad December 13, 2011 00:07

Reynolds for a rotary wing/blade
 
Hi dear All,

I want to know that when we are working with a wind turbine with a very long blade, for "Lift coefficient_ AOA" calculation which Reynolds number must be worked with.
I am thinking because in different radial positiions the velocity is changing according to the "Local R".

For example:
-Please consider the chorld length is constant;
-Velocity of wind is 10 m/s , and think R= 5 m , =7.5 Rad/s
So, the Relative Velocity at the tip = [ (10)^2+(5*7.5)^2 ]^ 0.5 ~ 39 m/s and then the Reynolds at the TIP will be 4 times the Reynold of free stream.
Now when we want to check the values of Cl-AOA , which Reynolds number we must consider? I think I must work with local Re and for different radial positions I must calculate Re number and work with that local Re.

Would you please tell me the answer for this question

ghorrocks December 13, 2011 17:12

Your comment about local Re number sounds about right.


All times are GMT -4. The time now is 06:52.