Numerical simulations of compliant material response to turbulent flow

Homogeneous and internally structured material coatings were studied numerically as candidates for drag and turbulence generated noise reduction on submersible hulls. Dynamic motions of compliant surfaces may conceptually interrupt random turbulent motions, reducing the turbulent interface stresses and absorbing turbulent energy, and consequently reducing the turbulence at the flow/coating interface. Time dependent, noninteractive, two and three dimensional Monte Carlo turbulent pressure field models, interactive potential flow models, and interactive Navier-Stokes pseudo spectral methods are used to represent the unsteady flow, while time-explicit finite element methods are applied to represent a variety of homogeneous layered, and internally structured material coatings. Attention is given to development and testing of an efficient but dynamically interactive fluid/solid interface coupling method, for two or three dimensional response simulations. The influence of added mass and of depth overburden on the material response in ocean water is discussed. Promising compliant material coatings include sandwiches of soft, homogeneous layers between thin, stiffer elastic materials and internally structured coatings combining streamwise ribs, spanwise voids and elastically deforming intervening stiffeners.