Modelling of wedge water entry problem by SPH method

Due to its importance in many practical applications in ship hydrodynamics and ocean engineering, the water entry problem is a challenging problem due to the modeling of instantaneous high pressures that occur during a collision of any arbitrary body to the fluid medium. Specifically, understanding of the physical phenomenon that occurs during the motion of a ship body provides useful information for optimization for structural endurance and motion stability. Numerical techniques enable us to obtain significant outcomes based on their theoretical background which is used to define the physical problem mathematically. During its motion in severe service conditions, a ship body is exposed to extreme and sudden pressure changes on its external shell structure causing impact loadings. In this manner, wedge entry phenomenon that may cause damaging impacts is because of fluid-solid interaction and shall be regarded as extremely important since its investigation provides useful information for the structural design and predicting endurance of the hull geometry. Numerical methods to solve mathematical models for such phenomenons can provide quantitative outcomes for pressure distribution over the region where fluid-solid interaction occurs. As an engineering approach, the cross-section of a ship body in two-dimension is geometrically approximated as a wedge and pressure distribution along the edges is investigated for various collision scenarios. Developments in the computational technology have provided faster computations and accelerated the to obtain numerical results. In time, computational power has spread in science and technology as well as in computational implementations of Smoothed Particle Hydrodynamics. The aim of this thesis study is to model the problem of access to the element numerically by using the Lagrangian particle based sph method. In this scope, a two-dimensional SPH algorithm was developed and a triangular body was first modeled at a constant speed to the calm water surface. The pressure distributions on the surface of the triangular body are calculated at the given sensor points of the experimental/numerical measurements in the literature. Furthermore, additional treatments which are known as viscous penalty method and fluid-solid interaction are coupled with weakly compressible smoothed particle hydrodynamics method and obtained numerical results are correlated with reference studies.