This paper presents numerical and experimental investigation of drag reduction on the micro-engineered surface, which is inspired by nature. Computational simulation has been performed to examine the flow characteristics on both smooth and rough surfaces, and an experimental investigation is conducted by using artificial super-hydrophobic surface fabricated by MEMS fabrication technique. The artificial surface is made of silicon wafer, where micro-structured with hydrophobic properties has been successfully mimicked. Effect of rough surface has been numerically examined by measuring the velocity profile and skin friction coefficient (cf) at grooves wall, which are compared with those of smooth surface. Unlike smooth surface, it is verified that the vortices flow are generated inside the valley of groove and affected the skin friction coefficient along the grooves wall to be small inside grooves valley region.
In this study we have experimentally and numerically analyzed the flapping mechanism and wing kinematics of coleoptera (Propylea japonica Thunberg). Using digital high speed camera, we captured the continuous wing kinematics and visualized the flight motion of the free-flying coleoptera. The experimental visualization shows that the elytra flapped concurrently with the main wing both in the downstroke and upstroke motions. In order to define the wing kinematics of coleoptera, the displacement of a wing cross section (50% span-wise) was measured for each sequence of the wing motion. Using these data, the flight motion of coleoptera was numerically simulated to investigate the aerodynamic performance. The computational aerodynamic simulation shows that leading edge vortex shedding plays a key role in generating lift to keep the insect aloft.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.