600 



- 6 - 

 APPENDIX 

 Symbol 9 . 



p. = incident pressure. 



p = maximum pressure of pressure pulse, 



n = decay constant of pressure pulse pj = p e' 



p' = relief pressure due to motion of diaphrajm, 



a = radius of diaphragm. 



h = thickness of diaphragm. 



p = mass density of water. 



■nt 



p = mass density of diaphragm.. 



c = velocity of sound in water. 



h. = effective thickness of diaphragm due to layer of water following 

 the motion of the diaphragm, 



= . . i!il^ 



10 5 Trp 

 -q - moan deflection of diaphragm, 



t = time, 



p = arbitrary pressure unit, 

 p, F(-i) = static pressure required to produce non-dimensional mean deflection -Z, 



/3 P, a' 



■77 a Pj 

 Other Symbols are defined in the text. 



Sutjscripts to i and <f. denote integration:- 

 ,1 



■?„ (T) = 



Jo 



Vl (^' '"'■■ *n 'x' = I '^n-l t") "*' 



2. Equation of notion of diaphrasm . 



The incident pressure pulse is assumed to be 



p. = p e-"t 

 ^ \ "^0 



while the pressure at any point of the diaphragm is 

 P = Pi - P* 



(1) 



(2) 

 where 



