OVALLING OSCILLATIONS OF CANTILEVERED CYLINDRICAL-SHELLS IN CROSS-FLOW - NEW EXPERIMENTAL-DATA

This article deals with an experimental investigation of the ovalling phenomenon for clamped-free cylindrical shells in cross-flow. From the interpretation of the data, conditions for two-dimensional and three-dimensional flows independent of a gap at the free end of the shell are deduced. In two-dimensional flow conditions, the nondimensional ovalling onset fluid velocity is observed to vary linearly with the Scruton number, a nondimensional form of the modal damping. A hysteresis is also observed in the shell ovalling vibrations, two steady amplitudes being possible for a given fluid velocity. From the data it can be inferred that ovalling is triggered whether regular vortex shedding is present or not and that the shell ovalling motion disturbs regular vortex shedding. (C) 1995 Academic Press Limited