Motora and Koyama 



Though the heaving force acting on a circular 

 cylinder has been calculated by Cummins (8), it is 

 necessary for us to calculate the inertia term and 

 buoyancy term separately. An approximate calcula- 

 tion was done making use of the Eq. (4), i.e., it was 

 assumed approximately that a summation of the 

 inertia term for a cylinder and for a strut would 

 give the inertia term of the total body. The same 

 assumption was applied for the buoyancy term. 



For the inertia coefficient k^ of a circular cyl- 

 inder, values given by Yamamoto (9) were used, and 

 for that of a strut, values given by Tasai (10) for 

 full section were employed. 



Fig. 1 - Geometry 

 of circular cylinder 

 type models 



Calculated inertia force and buoyancy for dif- 

 ferent breadth of the strut are as shown in Fig. 2. 



Fig. 2 - Calculated inertia force and buoyancy 

 for different breadths of the strut 



386 



