Water Entry and Exit of a Horizontal Circular Cylinder

Abstract

This paper describes the fully nonlinear free-surface deformations of initially calm water caused by water-entry and water-exit of a horizontal circular cylinder with both forced and free vertical motions. This has relevance for marine operations as well as for the ability to predict large amplitude motions of floating sea structures. A new numerical method called the CIP (Constrained Interpolation Profile) method is used to solve the problem. In this paper, the circular cylinder and free surface interaction is treated as a multiphase problem, which has liquid (water), gas (air) and solid (circular cylinder) phases. The flow is represented by one set of governing equations, which are solved numerically on a non-uniform, staggered Cartesian grid by a finite difference method. The free surface as well as the body boundary is immersed in the computational domain. The numerical results of the water entry and exit force, the free surface deformation and the vertical motion of the cylinder are compared with experimental results, and favorable agreement is obtained.

Fluid–structure interaction during the impact of a cylindrical shell on a thin layer of water

“…Greenhow (1988) used a boundary element method based on Cauchy's theorem, and Zhu et al (2005) used a CIP method. These studies assume rigid bodies.…”

Numerical Simulation of Water-Entry and Sedimentation of an Elliptic Cylinder Using Smoothed-Particle Hydrodynamics Method

“…In order to quantitatively verify the obtained numerical results, the depth of penetration of the cylinder obtained from the experi mental data of Greenhow and Lin and the CIP numerical results of Zhu et al [37] have been compared with the results of the (a) Fig. 11 Tim e variation of the (a) nondim ensional depth, and ( b ) vertical nondim ensional velocity of th e horizontal elliptical cylinder for various specific gravities during the water-entry case present SPH method for the water-entry and freely rising cases in the left column of Fig.…”

Numerical and experimental investigation of a three dimensional spherical-nose projectile water entry problem

“…Although potential-flow based numerical methods have been successfully employed in solving the water entry problem, it is difficult for these methods to treat highly distorted or breaking free surfaces. The problem is more severe when there is a compressed air layer between the body surface (with small deadrise) and the free surface (Zhu et al, 2006). The computational fluid dynamics (CFD) methods which are based on solving the Navier-Stokes equations can overcome these difficulties.…”