RADIATION INSTABILITY OF A CIRCULAR-CYLINDER IN A UNIFORM-FLOW OF A 2-LAYER FLUID

A solution of the plane linear problem of the oscillations of a horizo ntal circular cylinder in a uniform flow of a two-layer unbounded flui d is obtained using the method of multipole expansions. The direction of the Bow is perpendicular to the cylinder axis. The whole cylinder l ies in the upper or lower layer. The fluid is assumed to be ideal and incompressible, the flow in each layer being a potential one. All the components of the radiation load (the apparent masses and damping coef ficients) are determined and the regions of existence of radiation ins tability are found, depending on the Bow velocity for a cylinder suspe nded by horizontal and vertical elastic links. By solving the integro- differential equation numerically the relative oscillations of the bod y under specified initial conditions are found. (C) 1998 Elsevier Scie nce Ltd. All rights reserved.