An example calculation of the fundamental mode of 

 vibration for cavity No. 2 will serve as an illustration of 

 the application of the above relations. The inside dimen- 

 sions of the cavity are 12 x 8 x 10 inches, the latter num- 

 ber being the depth. The cavity walls are stainless steel 

 sheets of 24-mil thickness. Using a specific gravity of 

 stainless steel equal to 7. 9, the correction A I for each 

 wall is 190 mils or 0. 19 inch. 



The cavity is open on the top and was employed with 

 the water level always 0.2 5 inch below the rim. The effec- 

 tive cavity dimensions (using A I - for the free surface) 

 are accordingly 12. 38 x 8. 38 x 9. 94 inches. For the 

 fundamental mode of vibration (n , n 3 , n 3 being 1, 1, 1 

 respectively), the effective wave numbers for the cavity 

 are accordingly 



k , k~ , k~ 



TT 17 TT 



i' 2' s 12.38 8.38 9.94 

 in units of radians /inch. This yields 



h * = 0. 17575 tt 

 i 



5.69 



and from the first of relations (66) 



2 TT/ = 



no 

 5.69 



/ = 0. 08787 o 



For the temperature and salinity conditions of 60°F and 



34 gms/kg, the value of c from standard tables is 4935 ft/sec 



53 



