Session: 08-06-01 non-presentations

Paper Number: 124819

124819 - LNG Carrier in Regular Waves: CFD Comparison to Existing Experiments 

The evaluation of a ship’s performance in seaways is crucial for passenger comfort, fatigue and operating costs. With growing computing power proper CFD predictions become increasingly attractive. However, an integral part is their validation. This paper contributes a comparison of model scale RANS simulations to existing model tests and simplified linear approximations. The corresponding experiments have been conducted during the EU project Extreme Seas at TU Berlin.
A LNG tanker model was equipped with pressure sensors at bow and stern, water gauges on deck and sensors capturing the bending moment. The model was subjected to different wave fields and assessed in terms of rigid body motion, vertical bending moment (vbm) as well as green water and slamming.
In this paper the ship motion and the vertical bending moment of an LNG carrier are investigated and an assessment regarding green water effects as well as pressure impulses due to bow and stern slamming is presented. Simulations were performed using the finite volume method. The comparison to experimental data is based on time series, statistical parameters and on RAOs for heave, pitch and bending. The experiments reveal a decrease of vbm near the maximum predicted by the corresponding RAO. In this work we attempt to capture this effect numerically.
Regular waves with varying wave length are applied with two different steepness derived from Stokes II and III wave theory while the ship is kept stationary. Simulations are conducted with StarCCM+ using RANS with wall-modelled flow. The 6-DOF rigid body motions are realized using overset meshes.

Presenting Author: Cedric Fallet Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) / German Aerospace Center

Presenting Author Biography: Cedric Fallet holds Bachelor's degree in mechanical engineering and a Master's degree in aerospace from the Technical University of Braunschweig. During his studies he focussed on numerical methods for the solution of fluid flow problems and conducted research for two acceleration methods used in CFD solvers and reduced order models for the the prediction of aerodynamic data. His current work at the DLR comprises the exploration and application of numerical methods for the prediction of seakeeping.

Authors:

Cedric Fallet Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) / German Aerospace Center
Tobias Lampe Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) / German Aerospace Center
Dag Feder Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) / German Aerospace Center
Marco Klein Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) / German Aerospace Center