Prediction of wave-induced loads on ships: Progress and challenges

Numerical studies on effects of slosh coupling on ship motions and derived slosh loads

https://bib.irb.hr/datoteka/910471.1-s2.0-S0029801817306285-main.pdf

CFD verification and validation of green sea loads

Numerical research on time domain ship motions coupled with sloshing at different liquid levels and forward speeds

Green sea loads in irregular waves with Finite Volume method

The present work describes the development of an approach to study the problem of ship motions coupled with internal sloshing effects. A hybrid solution algorithm is developed that integrates a three-dimensional potential flow solver for ship motions into a viscous flow solver for sloshing loads. A three-dimensional time-domain forward-speed boundary element method (BEM), based on the transient Green’s function technique, is employed to capture the external ship hydrodynamics, while the open source finite volume method (FVM)-based solver, OpenFOAM, which incorporates an incompressible multiphase viscous flow model into an interface-capturing volume of fluid (VOF) technique, is employed to capture the internal sloshing hydrodynamics. After the individual solvers are validated against the experiments and other computations available in the literature, the solution from the coupled solver is discussed, and the influence of the coupling effects of sloshing loads on ship motions is brought out.

Numerical Studies of Coupling Effect of Sloshing on 3D Ship Motions

The nonlinear ship-wave interaction phenomenon occurring when the relative free surface motions exceed the free board of a vessel is studied using RANSE based Computational Fluid Dynamics. Present work illustrates a methodology developed using an unsteady RANSE based CFD tools to simulate complex green water flows and determine rate of water ingress into open holds of container ship. The methodology involves modeling appendages, open holds and generation of irregular waves. Simulations are performed on an open top container vessel operating in long crested irregular seas for one case as specified in the model test procedures given by IMO. Numerical computations of motion responses and rate of water ingress are compared with experiments.

Numerical Simulations to Compute Rate of Water Ingress into Open Holds Due to Green Waters

Numerical Studies on Slosh-Induced Loads Using Coupled Algorithm for Sloshing and 3D Ship Motions

There is an increased drive in solving complex ship and offshore hydrodynamic problems using viscous flow computations. Reliable seakeeping computations demands for accurate generation of waves. Present work demonstrates the simulation of numerical wave tank capable of generating regular and irregular waves with forward speed and current effects. Waves are generated according to velocity inlet method using a homogeneous multiphase flow model. The forward speed effects are accounted as an equivalent current. The main emphasize of present work is to generate and validate irregular waves; irregular waves are generated according to JONSWAP spectrum. The free surface elevations and sea spectrum are evaluated against theoretical computations. Treatment of outlet boundary condition and domain initialization is discussed.

Simulation of Numerical Wave Tanks for Generating Irregular Waves and Forward Speed Effcts

Design slosh-induced loads are estimated through short-term and long-term approaches based on numerical simulations. Long duration sloshing simulations are performed using multiphase volume of fluid (VOF) based finite volume method (FVM). Slosh coupling effects are considered in determination of tank excitations. The slosh coupled ship motion solver which combines transient Green function based time-domain boundary element method (BEM) solver with viscous finite volume method (FVM) solver is employed for seakeeping analysis. Methodology used for statistical evolution of pressure is demonstrated by considering a case study. Identification of suitable probability distribution function (Weibull 3-parameter or Generalized Pareto) is found to be essential at several stages based on the fill condition and nature of impact.

Jai Ram Saripilli

Papers

Numerical Studies of Coupling Effect of Sloshing on 3D Ship Motions

Numerical Simulations to Compute Rate of Water Ingress into Open Holds Due to Green Waters

Numerical Studies on Slosh-Induced Loads Using Coupled Algorithm for Sloshing and 3D Ship Motions

Simulation of Numerical Wave Tanks for Generating Irregular Waves and Forward Speed Effcts

Estimation of Design Slosh-Induced Loads Using Numerical Simulations