' ABSTRACT 



Y 



The forces and tnouianto acting on a 

 suboersible are computed whets it ie 

 beneath the free surface or near a wall. 

 The taethod used in this report is baeed 

 on potential theory. In th« computation 

 of forces and moments on the hull, a 

 three-dinensional method Is applied. The 

 free surface condition is linearized and 

 the body boundary condition is exact. 

 The body surface is discretized with 

 surface elements and the singularity of 

 source and sink is distributed on thea. 

 The strengths of the unkovra sources and 

 sinks are determined through the body 

 boundary condition. A two-diisensional 

 Eethod is applied to compute forces and 

 roocents of the^/control ''surfaces. The 

 boundary conditions ar&saae as those for 

 three-diisenslonal case. Computed forces 

 and noaente of the control planes are 

 added to those of the bare hull. To 

 include the interference effect of the 

 hull on the control planes, the flow 

 velocity at each control plane is 

 computed with existence of the hull. 

 There are some discrepancies between 

 coeputed results and experimental data 

 because of the effect of viscosity* The 

 overall trends in the computed results 

 are same as those of the experiments. -<£— 



ADMINISTRATIVE INFORMATION 



The work described below was perforsed for the Naval Sea Systea Command 

 (N'AVSEA), Funding was provided under Work Unit Kusber 1563-172. 



