that the vertical force component is in good agreement with experimental results; it 

 is also of the same type as that obtained by Schiffman and Spencer. 



A new method of investigating the oblique entry of a cone has recently been 

 developed by A. Coombs (1956) with promising results. In this method the pressure 

 distribution along a generator is assumed to be the same as that over the correspond- 

 ing generator of a cone of the same apex angle when entering vertically into a conical 

 water surface. The basic assumptions of this technique are illustrated in Fig. 5; the 



Figure 5. Strip theory for oblique water entry of cone. 



pressure distribution along the generator OB of the top diagram is assumed to be the 

 same as that over the cone BOB' shown in the lower left hand diagram. Similarly 

 correspondence is assumed for conditions on generator OA and cone AOA'; also for 

 generator OC and cone COC. 



IV. The Steady Cavity Phase: Axi-symmetric Problems 



Hydroballistics is mostly concerned with the motion of bodies of revolution 

 and it is unfortunate that much of the extensive exact theory of two dimensional 

 cavity flow cannot be applied directly to hydroballistic problems. During the past 

 few years, research on the axi-symmetric problem has concentrated mainly on a. the 

 development of analytical techniques capable of solving the exact differential equations 

 and b. methods involving similarity between plane and axi-symmetric flows. 



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