Sohreiher J Bentkowsky and Kerr 



sources; the body, the shroud ring, and the thrusters. 



^external = ^body + ^shroud "*" ^thruster • 



The following sections will discuss the simulation of these three 

 classes of forces. 



BODY FORCES 



The forces on the body can be divided into several types: 

 the static forces, Fbgjjy static » associated with buoyancy and weight 

 and the dynamic forces, F^Q^jy dynamic "which depend on vehicle 

 motions with respect to the water. 



Static Forces 



The weight or gravitational force ( W) acts in the Z direc- 

 tion and the buoyancy. A, acts in the -Z direction. The total 

 vehicle weight, W, can be best expressed as the vehicle weight 

 when In neutral trim Wq = A plus the change In variable ballast 

 from Initial conditions. The resulting static forces on the body are: 



F body, static = i^o '^L'^ii - ^) 



- sin e 



sin <^ cos 9 

 -cos 6 cos 9- 



The DSRV contains the following ballast and trim systems which will 

 affect the static forces on the vehicle: 



Main Ballast 



Variable Ballast 



Transfer Ballast 



Rescuee Ballast 



Mercury Trim 



Mercury List and BG Control 



In operation, the main ballast tanks are full when submerged. 

 The Transfer Ballast tanks are empty except when they are being 

 used in the dewaterlng process, and rescuee ballast is exchanged for 

 rescuees providing a constant value during submerged operations. 

 These systems do not vary during normal subnnerged operations and 

 therefore are not Included In the simulation. 



The tanks whose contents vary during submerged, unmated 

 operation are the variable ballast (Tg and T^) » trim (T4 and Tj) , 



1118 



