| Fundamental research on the aerodynamic performance of low Reynolds number airfoil has received increasing attention in the last decade,due to the rapid development and extensive application of UAV & MAV.At low Reynolds number,when the angle of attack is zero degree,the fluid flow through the surface of the airfoil,and the separation phenomenon will not appear.As the attack angle increases,the flow separates from the surface and forms laminar separation bubble gradually,and transits from laminar to turbulent.During this process,lift rises obviously.Whereafter,the separation bubble breaks and the lift declines sharply,and the stall phenomenon appears.It is important to realize the flow control methods which aimed at improving aerodynamic performance of low Reynolds number airfoil,both for the fundamental investigations and engineering applications.In the present study,the fur strip is installed on the airfoil to investigate the impact on the aerodynamic performance,including the time-mean lift coefficient,time-mean drag coefficient,lift-to-drag ratio,vortex shedding frequency and flow field.The range of Reynolds number is Re = 3.8 × 104 ~ 7.6 × 104.In this study,the fur strips with three different widths(w/c = 0.27,w/c = 0.53 and w/c = 0.8)at different positions on the airfoil,both on suction and pressure surfaces,so that we can iinvestigate the impacts on the aerodynamic performance of the NACA0012 airfoil.Based on the experimental results,we can see that in most cases,different Reynolds numbers play limited impact on the lift and drag of airfoil.Meanwhile with the fur strip installes on the suction surface,the stall phenomenon disappears,lift reduced.On the contrary,with fur strip installed on the pressure side,the stall angle tends to be declined as Reynolds numbers decreasing.At small attack angles(0° ~ 6°),there is a positive lift.The most optimum control performance is obtained with w/c = 0.8 fur strip installed on the pressure surface. |
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