The damping effectiveness of a bilge keel depends on the velocity of the flow and the roll period of the ship. The Morison equation defines the relation between these motion parameter and the forces acting on the bilge keel. Sarpkaya and O’Keefe published in 1996 an article with their results of several flow experiments conducted over a wide range of Keulegan-Carpenter period parameter. They provide the KC dependent drag and inertia coefficients obtained from the measured forces on a bilge keel and discuss the vortex pattern generated by the oscillating bilge keel.

In the present study the CFD code OpenFOAM was used to compute the flow around a bilge keel and the related forces. The numerical and experimental results are compared. Based on the test conditions a finite volume mesh was generated and the flow was computed with a transient, turbulent flow solver. In order to investigate the boundary layer on an oscillating wall and the dissipation of the vortex structures different turbulence models (kωSST, low Re and LES) were used. The experiments were conducted at zero forward speed. However, the computations were performed for different ship speeds.

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