Numerical study on drag-reduction mechanism of thermally conductive elastic bionic wall based on fluid-solid-heat coupling

Limei Tian, Yangjun Wang, Mingyao Gao, Yi Lin, Ziyuan Li, Yangeng Shang*

Key Laboratory of Bionic Engineering, Jilin University, Ministry of Education, China

The thermally conductive elastic bionic wall (TEW) has both excellent elasticity characteristic and distinct heat conduction feature, it can control fluid medium to obtain drag reduction through coupling characteristic between its elasticity and heat conduction performance, similar to the drag reduction mechanism of dolphin’s skin. In the present work, we were not just focusing on the drag reduction mechanism of flexible wall (FW); we paid much more attention to reveal the coupled drag reduction mechanism of TEW using the simulation method of the fluid-solid-heat. The ANSYS Workbench platform was used to simulate heat transfer and the fluid in the internal flow on three kinds of surfaces: rigid wall (RW), FW and TEW, comparative analyses of flow field, grid displacement, the resistance and temperature of boundary layer, dynamic viscosity, and average Nusselt number were conducted among those above. The results indicated that both FW and TES could reduce the drag of flow, and the TES had a better drag reduction than the others, which was due to its dynamic deformation and heat conduction feature. Energy dissipation occurred in the process of regular deformation under the action of fluid, which was expressed in the form of heat. The heat generated by deformation was transmitted to the surface of TEW by its thermal conductivity, reducing the dynamic viscosity of boundary layer. The dynamic deformation of TEW could improve the effect of boundary layer convection heat transfer and decrease the velocity gradient of the fluid boundary layer, resulting in frictional force reduction. This investigation provides a theoretical basis for future research studies to consider thermally conductive elastic bionic surface when augmentation of drag-reduction is sought.