fx = ∑i|v_xi| / L  =  n * Vx / L

fy = ∑i|v_yi| / L  =  n * Vy / L 


f = (Vx + Vy) * (n/L)



vx = v * cosu * cosw   (u:위도/ w:경도) 

vy = v * cosu * sinw


Vx = v * (∫[-π/2~π/2]|cosu|du / π) * (∫[0~2π]|cosw|dw  / 2π)

= v * 4/π²

Vy = v * (∫[-π/2~π/2]|cosu|du / π) * (∫[0~2π]|sinw|dw  / 2π) 

= v * 4/π²


f = 8nv / (π²L)





(사진)

f(n,v,L) = f(20,2m/s,21*0.5m) ≒ 3.08Hz