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keith0101
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- Why we take area of disc, instead of area of ambient air in the assumption of mass flow rate when calculating the available wind energy? Isn't it a contradiction to conservation of mass?
For the avaliable power to be harvested in free-streaming wind:
P=1/2QU^2_infinite (Q: mass flow rate, U_infinite: velocity of free-streaming wind)
And
Q is defined as: p x U_infinite x A_d. (p: density of air, A_d: Area of disc)
I cannot understand the reason of taking the area of disc, A_d, instead of area of ambient air, A_infinite, in the assumption of Q, since under the conservation of mass:
p*U_infinite*A_infinite = p*U_d*A_d = p*U_w*A_w
P=1/2QU^2_infinite (Q: mass flow rate, U_infinite: velocity of free-streaming wind)
And
Q is defined as: p x U_infinite x A_d. (p: density of air, A_d: Area of disc)
I cannot understand the reason of taking the area of disc, A_d, instead of area of ambient air, A_infinite, in the assumption of Q, since under the conservation of mass:
p*U_infinite*A_infinite = p*U_d*A_d = p*U_w*A_w
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