A fluid force deduction technique for vibrating structures in cross-flow

Abstract

An experimental technique is introduced for deducing the unsteady fluid forces, F(t), on elastically vibrating structures using their oscillation trace y(t) , and the free stream velocity U. This new technique involves an accurate modeling of the elastic structure as an ordinary differential equation and employing time-dependent oscillation traces, y(t) and/or the acceleration a(t), to extract the side force on the structure. Filtering the oscillation signals and modeling the non-linear damping terms in the structural equation turn out to be the challenges of this technique. This technique may be applied in force studies relating vortex patterns and the the unsteady forces as well as methods for predicting or modeling fluid forces and amplitudes. Although the results are not compared with any independent technique, the unsteady lift coefficient traces show high values of above three as observed by other researchers.

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