possible to rapidly compute the source strengths corresponding to a 

 number of propeller onset flows as 



r. = ZC-}. V. 

 1 *r' XT 1 



(10) 



Once the body source strengths are known, it is straightforward to 

 compute velocities and pressures at points on the body surface or in the 

 surrounding field. It is also possible to determine the resultant force 

 acting on the body as described below. 



SOLUTION FOR THE THRUST DEDUCTION 



In general, the influence of a stern propeller causes a net increase 

 in the hull resistance. Two methods are available to compute the force 

 exerted on the body. In the first approach, the axial force, F , is 

 derived by integrating the pressure over the body surface. 



F = e 



X s 



i 



P(r,) - P(r^) 



with without 

 propeller propeller 



ri(rg) dS(rg) 



(11) 



where the pressure is found from Bernoulli's equation 



p = --^V • V 



(12) 



The velocity is computed at the control points of each quadrilateral as 



V.(r^) = 11^ o. V 

 J 



AS. + V + 



(r. ) 



A distinct advantage of this method is that the effect of body foirm can be 

 determined by examining the distribution of the pressure integral. Also, a 

 detailed knowledge of the pressure distribution is an important first step 

 in solving the viscous flow over the afterbody. 



