Coupling Function and Mechanism of the Bionic Coupling Functional Surface (BCFS) Caused by the Dual Factors of Form and Flexible Material

Abstract

Some living creatures have special structures on their body surfaces, such as smooth and elastic epidermis with subcutaneous tissue having non-smooth structures under certain conditions. The elastic epidermis coupled with non-smooth structures has a special function called bio-coupling functional surface. Imitating this functional surface and applying it in engineering has a potential to solve some engineering problems. Based on the simulation method of fluid-structure interaction (FSI), simulation calculation of the bionic functional surface coupled by the two factors, form and flexible materials was conduct using ADINA software. A viscous and weakly compressible transient flow was selected as a working medium, a discrete solver was selected in numerical calculation and the basic model was chosen as a turbulence model. It is assumed that the coupling surface of the form/flexible materials results is large deformation and large strain. The boundary condition of fluid-structure interaction was set as the calculation surface. The simulation results showed that this coupling is a dynamic process, in which the two factors (form and flexible materials) are influenced by the flow field. As the pressure and velocity of the flow field increase, the coupling process changes from partial coupling to complete coupling, the pressure drag decreased due to the maximum effective stress of bionic coupling surface is very small and the smooth and flexible materials can redistribute pressure by absorbing and releasing energy, the pressure drag thus formed is decreased. Moreover, non-smooth structures (form factor) coupled with flexible materials reduced velocity of working face and minimise energy losses effectively, enabling the bionic coupling surface to reduce drag.