Simulating the Detachment of Leading Edge Vortices on Drosophila Melanogaster Using CFD

Abstract

Abstract : Initial CFD simulations of quasi-steady hovering flight of the Drosophila sp. have studied the effects of delayed rotation of the wings at the end of each stroke and it s effect on the resulting unsteady aerodynamic forces found throughout the wing [8]. Further studies were carried out using the same CFD model as before to determine the lift and power requirements for Drosophila Virilis [7]. To verify the validity of the simulation s results, the specific power that was calculated (the sum of aerodynamic and intertial power requirements normalized to the fruitfly muscle mass) was compared to the values retrieved by Dickenson on tethered fruitflies [1]. Although the periodic behavior of the translational and rotational motions of the wing were heavily approximated, the comparison showed strong agreement. This lends support to the use of CFD models in the parametric design process used in the pioneering of microscale flapping wings [2]. It is of great importance to MEMs designers working on microscale flapping wing to study the detachment of Leading Edge Vortices (LEV). Solving the Navier-Stokes equations in the time-varying coordinates of the flapping wing proves a challenge computationally but offers the possibility of predicting the behavior of the LEV-shedding phenomenon to which flapping wings owe a majority of their lift. In addition to studying the shedding of LEVs, CFD simulations enable one to quickly assess the effect of wing shaping on vertical lift. Preliminary code was developed in MATLAB with these two potential studies in mind. The code that was developed to tackle the flapping wing problem solves the Navier-Stokes equations for a compressible fluid.