Experimental investigation of the load exerted by nonstationary internal solitary waves on a square column beneath an ice keel

Abstract The safety of marine structures and underwater vehicles is seriously threatened by the nonstationary internal solitary waves (ISWs) beneath an ice keel. Laboratory experiments were conducted in a stratified fluid flume to examine the load characteristics of the square column that is exerted by nonstationary ISWs beneath an ice keel. The ISWs and its load on the column are measured by using conductivity-probe arrays and an underwater force measurement platform, respectively. The experimental results show that the evolution characteristics of ISWs are significantly changed by the ice keel, resulting in differences of the forces at different horizontal positions. The horizontal and vertical forces were measured as a control at the front slope. Subsequently, the magnitude of forces decreases significantly and direction changes at the bottom. At the back slope, the magnitude of the forces slightly increases, the direction remains unchanged, and the duration of the force decreases. The structural characteristics of nonstationary evolution of ISWs exhibit significant differences at different depths. When the envelope of the ISWs can come into contact with the column, the direction of forces remains unchanged and the magnitude decreases as the depth increases. Conversely, the magnitude becomes very small and the direction changes.