Loading on rounded square foundation elements of offshore structures with marine growth at incidence

Abstract

A systematic wind tunnel study is performed to identify the mean and fluctuating loads experienced by a 2D square prism with non-dimensional rounded edges of r=D = 0:16 and covered with hard marine fouling for Reynolds numbers between 70,000 and 8 million. The incidence angle is varied from a=-45 to 3.25 deg. with increments of 3.25 and 6.5 deg. . The critical angle of incidence, at which a reattachment of the free shear layer takes place on the lateral windward directed side surface, is found at acr =-6.5 deg. . For a acr. For the latter angles of incidence, a decrease towards -45 deg. induces higher values of CD and the r.m.s. of the lift fluctuations, as well as lower Strouhal numbers and mean lift forces.