SURGES FROM WINDS NEAR A CIRCULAR ISLAND

A uniform asymptotic analysis of unsteady storm surges due to surface winds of the form S(r)exp(- i omega t) H(t), z = 0, [r = root x(2) + y (2), H(t) = Heaviside unit function], near a circular island r = a is carried out for large times and distances. Assuming that the undisturb ed depth is h(1)(r/a)(alpha) for r > a, with alpha greater than or equ al to 0 and h(1) = constant, some interesting features of the motion a re described. These include, amongst others, several characteristics a long with a graphical illustration of the asymptotic envelope of the d ominant progressive long wave generated.