Compliant material coating response to a turbulent boundary layer

The results of transient, two-dimensional finite element computations used to simulate elastic and viscoelastic surface response to the stress generated by the surface turbulent boundary layer in water are described. The temporal and spatial response of soft, pliable surface coating materials such as natural rubbers, artificially treated rubber-like compounds, and cured polymeric gels are characterized. A variety of coatings from stacked homogeneous layers to internally structured layers with open and fluid filled cells or with directional ribs and channels are examined. In addition, nonlinear viscoelastic loss characteristics and time-dependent influences on material response are examined. The goal of this investigation is the identification of drag, and the characterization of the most important dynamic material properties to achieve this end. Two-dimensional transient numerical computations are applied to simulate the space and time random scalar pressures which excite the material response.