Static Stability And Motion Response Of Steel Cylinders Block In The Wave

The steel cylinder block is made up of four large diameter cylinder. To aerate atthe bottom, and the block is towed in wave. The static stability and motion responseof steel cylinder block in the wave are studied in this paper.The concept of air floating decrease coefficient was introduced and thecomputing method about correlative parameters and stability indications of staticstability were studied considering the geometry parameters, air pressure and differentdrafts. Based on the theoretical methods of the statics of the ship, computing methodon static stability of steel cylinder block is given, the stability properties of thestructure block made up of four steel cylinders whose diameter is 10.5m werecalculated under six kinds of drafts and different aeration heights, the initialmetacenetric height of the structure block was obtained, and the stability wasevaluated under different floating conditions.The wave loads computing method and the mathematical prediction method ofthe structure system motion response were studied by using diffraction theory,radiation theory considering the wave parameters ,air pressure. The water column wassimplified into moving piston and the high pressure is dealt with gas springs, then thecomputation model of motion for steel cylinder block was put forward. Thediffraction velocity potential was solved by wave potential flow theory and theboundary progressive matching method, then the wave loads acted on the steelcylinder block were gained. By the boundary progressive matching method, theradiation potential of the steel cylinder block was calculated, the added-masscoefficient and added-damping coefficient of the steel cylinder were obtained . At last,the wave loads and motion response of the structure block made up of four steelcylinders were calculated. The results show that the method in the paper is practical.