Numerical Simulation Of Slamming Induced Loads On Three Dimensional Structures With Various Angles

The bow section of a ship will be impacted by hydrodynamic force when it travels in rough seas.The impact force-“Slamming Load”-on the local structure,then spreading to the entire hull,will cause damage and deformation.High frequency vibration response is also generated throughout the entire ship hull.Therefore,the ship sailing in the oblique waves with roll motion,assessment of slamming load with small angles is of great significances to study the safety and movement responses for marine structures.In view of the vertical water entry problem with the angles,most researchers study the two-dimensional model,which has less influence on the three-dimensional effect of the structure.Numerical simulation research using CFD technology which is based on Finite Volume Method,cooperated with VOF(free surface capturing technology)and Dynamic Mesh Method was made.This work focuses on the assessment of total vertical slamming force,the vertical acceleration,pressure distributions at different time instances,pressure distributions along the Z direction and pressure histories on the wetted surfaces of typical rigid bodies of the three-dimensional structures in the process of the entry water.The secondary impact,the ventilation and air pocket phenomena are discussed in detail.The numerical simulation results are in good agreement with the experimental data,which verifies the feasibility of the CFD technique in the prediction of the impact pressure load.The simple geometric model,the wedge slamming test with angles is investigated firstly,and then analyzes Bow-flare drop test with various angles.Furthermore,the effects of the roll angle and the velocities of entry on the slamming loads are investigated through the calculations for the Bow-flare section with different roll angles which include 0°,4.8°,9.8°,14.7°,20.3° and 28.3°,wedge section with various height which include 0.3m,0.5m,0.75 m.The pressure distributions along the Z direction in three-dimensional is emphasized in the thesis.On the basis of previous research,research on the slamming load with angles of structure is benefit to understand slamming loads in oblique waves,and providing a reliable basis for the researchers to study slamming problem in theoretical and engineering application field.