2D quasi-steady flow simulation of an actual flapping wing

[[abstract]]This paper deals about the dynamic behavior of flapping wing with an aid of stereo photography measurement using charge coupled device (CCD) camera. The three dimensional (3D) flapping motion was captured and coordinates are measured with the specific markers on the wing. The curved surface fitting was obtained from the 3D discrete coordinates using SURFER software. Consequently, a two dimensional (2D) cross section of flapping motion of the wing surface is sliced from 3D mesh. It was used further for the quasi-steady state computational fluid dynamics (CFD) simulation in Fluent. Utilizing two adjacent 2D trajectories, the upwind direction of flow filed was computed in this study. The computed dynamic velocity was considered to be input for the CFD analysis. The velocity and pressure distribution due to quasi-steady state flapping motion is observed in Fluent. The unsteady lift coefficient was obtained which was compared with experimental results from the wind tunnel. It was observed that, both theoretical and experimental results shows similar trend to validate the assumptions considered in the study.[[notice]]補正完畢[[journaltype]]國外[[ispeerreviewed]]Y[[booktype]]電子版[[countrycodes]]KO

Dynamic stability in vertically flying insect-mimicking flapping wing system

This paper provides a quantitative analysis for the longitudinal dynamic stability of a vertically flying insect-mimicking flapping wing system (FWS. In order to define the parameters in the equation of motion, the computational fluid dynamics (CFD) by ANSYS-Fluent was used. The aerodynamic forces and moment when the FWS was installed vertically and then inclined -15 and +15 degree for flight speeds of 0, 0.2 and 0.4 rn/s were computed. Through the eigenvalue and eigenvector analysis of the system matrix, we could make the formal description of the dynamic stability of the FWS. Three modes of motion were identified: one stable oscillatory mode, one unstable divergence mode, and one stable subsidence mode. Due to the divergence mode, the FWS eventually becomes unstable. However, the FWS could stay stable in the vertical flight during the first 0.5 second