ANALYSIS, PREDICTION & OPTIMIZATION OF THE HYDRODYNAMIC PROPERTIES OF WIND-ASSISTED OR FULLY WIND-PROPELLED SHIPS
Fabian Thies1*, Moritz Schaefer1, Francesco Coslovich2, H. Renzsch1
1 Friendship Systems AG, Potsdam, Germany
2 Flowtech International AB, Gothenburg, Sweden
ABSTRACT
In new design and retrofit projects where wind propulsion is applied, it is crucial to quickly and accurately predict the hydrodynamic properties of the hull or hull variants. Since wind propulsion introduces large side forces which lead to drift angles and yaw rotations causing added drag, the evaluation of such forces and their center of effort, i.e. the center of lateral forces (CLR), is of big interest. On the example of the KVLCC2 and a Kamsarmax bulker, this study decomposes the hydrodynamic forces and moments acting on a drifting hull into potential flow lift, cross flow drag and its center, as well as the Munk moment. The study proposes a suitable workflow on how to accurately predict the hydrodynamic properties of a drifting ship using CFD. The suitability of surrogate and empirical/ theoretical methods to reduce the necessary amount of CFD computations is discussed. Further hull variations are applied to research into how the hydrodynamics are influenced by the hull design, i.e. the main dimensions as a first step.
The results of the study are a better understanding of the hydrodynamics of drifting ships and a proposed workflow how to estimate the side force, drag and center of lateral resistance in a time efficient manner.
