Numerical Seakeeping Analysis for a Floating Helicopter after Ditching in Waters

Abstract

This paper investigates the seakeeping behavior of helicopters after an emergency landing in water, focusing on a Northern North Sea wave climate and considering a realistic helicopter geometry. Computational Fluid Dynamics (CFD) techniques, including the cell-centered Finite Volume Method and Boundary Element Methods (BEM), were utilized to analyze motion responses and load distribution. The study ensures numerical result reliability through best simulation practices. Results indicate that the inviscid model produces similar outcomes to the viscous model in decay tests with roll, pitch, and heave motions. Natural periods for roll, pitch, and heave motions were obtained. Linearity between incident wave amplitude and pitch/heave response was noted for regular waves, while roll linearity was limited for small angles. In irregular wave conditions, helicopters tended to align perpendicular to waves over time, resulting in increased peak roll angles with higher significant wave heights. Exceedance rates of maximum roll peaks, useful for the assessment of capsizing probability, were quantified for different significant wave heights.