A numerical method developed from earlier work [1, 2] of predicting damping due to eddy shedding from sharp or rounded bilges of a hull of arbitrary cross-section in beam waves is presented. The method matches an inner solution which simulates the local bilge section separated flow numerically to an outer wave potential flow solution. The latter can be any standard 3-dimensional panel or other method for the whole body which provides the local values of the matching velocity parameter at all bilge sections which shed eddies. Scaling by the matching parameter provides a physically based sectional damping coefficient for a response computation. In the case of free response of a floating body feed-back from the viscous damping to the bilge velocity parameter through the response mode amplitudes necessitates iteration which generally converges very quickly.

Computational predictions carried out in the frequency domain using this prediction method assuming linear wave theory for the outer flow are presented and compared with laboratory wave tank measurements for roll response of two floating hulls in regular and random waves. Application of the method to viscous damping of more complex geometries is also possible.

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