278 



- 10 - 

 TABLE 3a. 



C riterion (g - j5) for appearance of cavitation according to 'rigid piston' 



assumption. 



Extreme cases are gauges of the crusher type, in which the thickness of the piston is 

 comparable with or greater than the radius. It will Be quite safe to apply incompressible theory 

 to such cases, but the smaller sizes of diaphragm gauge seem to be in or near the critical region. 

 For the box models one can deduce that extensive cavitation will occur, and the sare is likely 

 to be, true of ships' plates unless they are very much subdivided by stiffeners. 



TABLE 3b . 



Kirkwood's Criterion i3 - '^ a~r ~r '"9 °^ 'or appearance of cavitation according 



to assumpt ions. 



This 



