HYDROELASTIC INSTABILITY THRESHOLD IN A TURBULENT BOUNDARY-LAYER OVERA COMPLIANT COATING

In this paper we are concerned with a linear problem of hydroelastic i nstability in a turbulent boundary layer over a compliant coating of a ribbon-like material. A dispersion relation for hydroelastic waves is written in terms of complex stiffness coefficients that characterize the deformation of the compliant surface and the turbulent flow respon se to the wavy surface flexure. A membrane-type approximation is propo sed for the stiffness coefficient of solid coating at sufficiently low frequencies. In order to evaluate the turbulent flow response, the ed dy-viscosity model in a curvilinear coordinate system is employed. The quasipotential approximation for the description of flow stiffness is confirmed on the basis of the computations. The critical flow speed a nd the parameters of the hydroelastic waves at the instability thresho ld are determined both within general definitions for the stiffness co efficients and for their approximations. The computational results are compared with available experimental observations. (C) 1998 American Institute of Physics. [S1070-6631(97)04212-8].