Forces on an A.C.V. Executing an Unsteady Motion 



S side force coefficient, analogous to R 



c c 



t time 



w, u induced longitudinal and transverse wavenumbers 



W weight of craft 



x, y, z coordinate system travelling with craft, but not rotating with 

 it 



a longitudinal cushion pressure fall-off parameter 



j3 transverse cushion pressure fall-off parameter 



7 



Vgk' tanh (kd) 



yaw angle of vehicle relative to x axis (see Eq. (47)) 



free surface elevation 



wave direction with respect to the x axis 



longitudinal coordinate in the stationary reference frame 



water density 



initial position of model in the tank 



dummy time variable 



velocity potential in the stationary reference frame, such that 

 the velocity is its positive derivative 



Superscripts 



variable reffered to axis system moving and rotating with 

 craft 



dummy variable 



time differentiation 



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