Murthy 



15(A) 

 QA9) 



Cf (cos -j 



= //p (x, y) J k (xcos + ysin#) sec qJ dxdy 



// ° sin ° , 



S 



(6-35) 



These results agree exactly with those given by Havelock [6j for a 

 surface pressure distribution which is continuous and is zero at the 

 outer boundaries. 



We now come that part of the wave resistance which is due to 

 the interference between the air cushion and the side hulls. 



Referring to (6-23A) we shall not attempt to evaluate the inte- 

 gral over S\ for under the assumption made previously (i. e. with 

 small side hull immersion) the integral will be of (5 jS). The in- 

 terference of the air cushion on the side hulls may therefore be neglec^ 

 ted. 



The effect of the interference of the side hulls on the air 

 cushion is given by 



^V : = i"J/ p o *ioooxx (x ' y ' o) dxdy = 



interference 5„ 



o 



= "¥ 11 3£ axdy ll'W d ^ df [ G J x >y>°A'>*,!') + 



+ G x (x,y, o;^, -b, r)J (6-36) 



It does not appear that this double surface integral could be 

 reduced to the simple form of a single integral as in the case of the 

 hull resistance and the cushion resistance. 



VI . 4 Drifting Amphibious ACV 



The case of an amphibious hovercraft drifting in calm water 

 has been discussed in section 7 of Reference 1 and a solution for the 

 wave resistance in closed form has been obtained in the form 



2 */2 



1 

 — R 



2 W 

 /3 cushion ZirpV 



-tt/ 2 



S-y /[pV/3)+Q 2 (*.0)] 



roV J 



5 

 sec d d0 



156 



