Experimental and numerical investigation of beetle flight

We investigate the flight characteristics of the beetle (Allomyrina dichotoma), which has hind wings and elytra, based on the numerical simulation. Flapping kinematics of both the hind wings and the elytra are obtained by visualization in a wind tunnel. One can observe veins and membrane on the hind wings, which allow corrugated patterns on the cross section of the wing along streamwise direction. Therefore, we investigate details of the vein and membrane structures, which is able to be used for modelling the wing for the numerical simulation. The veins thickness ranges from 100 mum to 1000 mum, meanwhile, the thickness of the membrane is around 5 mum. Numerical results show that the corrugated cross section wing allows higher aerodynamic performance than the elliptic wing for the same flapping kinematics. The elytra have the positive contribution of vertical force during forward flight, while its effect is not significant when there is no income flow.