ON THE DETERMINATION OF AEROHYDRODYNAMIC 

 PERFORMANCE OF AIR CUSHION VEHICLES 



S.D. Prokhorov, V.N. Treshchevsky, L. D. Volkov 



Kryloff Ship Research Institute 

 Leningrad, U. S. S. R. 



ABSTRACT 



Experimental and theoretical methods of determi- 

 nation of hydro-and-aerodynamical characteristics 

 necessary for air cushion vehicles dynamic calcu- 

 lations are discussed. The influence of ship form 

 on mentioned characteristics corresponding to stea- 

 dy and unsteady motion is analysed. 



The estimation of propulsive performance and manoeuverabi- 

 lity characteristics of ACVs while designing these vehicles can be 

 based on tests carried out with self-propelled models and simulation 

 of various operational conditions for these models. It is obvious that 

 the model behaviour is governed in this case by the total aerohydrody- 

 namic loads which are different in nature. At the same time separate 

 definition of aero-and-hydrodynamic forces of various nature is of 

 interest, specifically, for the analysis of the effect some components 

 of these forces have upon the ACVs performance and dynamics. 



The forces acting on ACVs can be classified into the follo- 

 wing categories : 



a) aerodynamic forces due to the oncoming flow around the hull, flexi- 

 ble skirt, stabilizing fins and controls; 



b) aerodynamic forces due to the air cushion and interaction between 

 the latter and counter air flow; 



c) hydrodynamic forces due to the contact of the flexible skirt with 

 water surface and interaction between the air cushion and water sur- 

 face; 



d) hydrodynamic forces due to the effect of waves. 



The cruising conditions of ACVs are characterized by the 

 active interaction of the structural elements with both water and air 



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