Numerical simulation of flow around the Colorado micro aerial vehicle

Micro aerial vehicles (MAVs) are distinguished by their small size, low aspect ratio, and low velocity. As a result, MAVs fly at low Reynolds number flow regimes with significant drag characteristics and strong tip vortices. This investigation is focused on the aerodynamic characteristics of a recently developed MAV at the University of Colorado. The Colorado MAV has a flexible membrane wing with an aspect ratio of 1.2 and a chord of 0.27 m. Numerical simulations of the flow around the Colorado fixed wing MAV are presented using a steady state parallel compressible Navier-Stokes solver. The computational grid has 510,000 nodes and about 3 million tetrahedral elements. The maximum calculated lift coefficient is approximately 1.2. The airplane stall angle is at 30°. The high stall angle is attributed to the enhanced lift from a low pressure region above the wing caused by strong tip vortices. Minimum drag coefficient was calculated to be 0.06 at 2° angle of attack. A laminar separation bubble is formed on the upper surface of the wing at moderate angle of attack. The drag increases rapidly as the angle of attack increases. A maximum aerodynamic efficiency of L/D = 4 is observed when flying at 10 m/s.
QC 20141212