20 



(c'+iq'V 



Y2 Y4 



— [Jo(kD) CF.23 



+ 2 y (a cos nB + b sm nB)iTi J (kD) 

 ^, n n n 



n=l 



T J (kD)7r cos 2i 



N 



I 

 n=l 



± \ (a^cos(n+2)3 + b sin(n+2) 3) TTi""^^J^_|_2 (kD) 



N 



, n-2 



± y (a cos (n-2) B +b sin (n-2) B) Tri j _ (kD) ] 

 ^, n n n-2 



n=l 



for some frequency 6. The cross-spectral density of the absolute 

 pressure signal and x-axis and y-axis differential pressure signals 

 are respectively: 



(c'+iq') = k [J„(kD) cos 



nn.. 



N 



CF.3] 



n+1. 



+ y (a cos(n+l)g + b sin(n+l)B)Tri J _^t (kD) 



i- n n n+± 



n=l 

 N 



.n-1. 



+ y (a cos(n-l)B + b sin(n-l) 6) ttI J , (kD)J 

 '', n n n-l 



n=l 



