Nonlinear analysis of sloshing and floating body coupled motion in the time-domain. (15th September 2018)

• Record Type: Journal Article
• Authors: Huang, Shuo; Duan, Wenyang; Han, Xuliang; Nicoll, Ryan; You, Yage; Sheng, Songwei
• Is Part Of: Ocean engineering. Volume 164(2018)
• Page Start: 350
• Page End: 366
• Publication Date: 2018-09-15
• Subjects: Nonlinear time-domain simulation -- Sloshing -- ISITIMFB -- Energy dissipation; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2018.06.003
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: The aim of this paper is to develop a coupled nonlinear time-domain simulation scheme for nonlinear interactions among sloshing flows and floating body motion for both regular and irregular wave excitation. The contributions of a variety of nonlinear factors, outside waves and inside sloshing induced forces, as well as their influences on body coupled sway and roll motion were investigated. The induced forces are due to the changes in the transient wet surface of the floating body and full nonlinear sloshing. The effects of tank fill ratio and excitation wave height on the nonlinear coupled motion, as well as the relationship between sloshing and floating body nonlinear coupled motion under large wave amplitudes and severe sea conditions were also investigated and the results are presented. Finally, the numerical solutions are compared with existing experimental result. The fully nonlinear sloshing and floating body coupled motion are simulated based on the potential flow theory, with the transient position hydrodynamic assumption. The boundary value problem is solved by the B-spline higher-order panel method. The ISITIMFB (iterative semi-implicit time integration method for floating bodies) is applied to solve for the body's velocity and displacements. The sloshing energy dissipation is modeled by changing the boundary condition on the tank's solid boundaries. An extended principle to determine the energy dissipation coefficient for both regular and irregular cases is extracted. Then, the sloshing and floating body nonlinear coupled motion under large wave amplitudes and severe sea conditions are investigated, and the numerical solutions are compared with existing experimental results. The effects of tank fill ratio and excitation wave height on the nonlinear coupled motion is also investigated. Highlights: A time-domain method based on nonlinear potential flow theory is established to predict sloshing and ship coupling motion in large amplitudes regular and irregular beam sea. The present model help successfully approximate sloshing energy dissipation and so achieve the steady state of sloshing motion in a short time simulation. A modified wall boundary condition is given by ∂ ϕ ∂ n = U ⇀ ⋅ n ⇀ − μ g ∂ ϕ ∂ t | n Y | to consider sloshing energy dissipation. An extended principle to determine the energy dissipation coefficient μ in both regular and irregular cases is extracted. The nonlinear effects of inside sloshing and outside waves in coupling motion are emphasized. It is discovered that nonlinear sloshing is what affect the coupling motion the most, followed by nonlinear changes of floating body surface.