極低レイノルズ数領域での様々な二次元翼型の空力特性と流れ

<p>We have been requiring more precise knowledge about the aerodynamic characteristics of the airfoil especially in low Reynolds-number ranges less than 10⁶, because of the recent miniaturisation of robots such as unmanned aerial vehicles known as UAVs or drones and micro air vehicles known as MAVs, in addition to the importance of insect/bird flight dynamics, small-scale machines like micro fluid machineries and micro combustion engines and so on. In the present study, we investigate the relationship between various aerodynamic characteristics and attack angle <i>α</i> for flat plate NACA0015 and iNACA0015 (the NACA0015 placed back to front) by numerical analysis and water-tank experiment at <i>Re</i> = 1.0×10² － 8.0×10². Then, we investigate the effects of attack angle <i>α</i> upon various aerodynamic characteristics such as the lift coefficient <i>C_L</i>, drag coefficient <i>C_D</i> and the lift-to-drag ratio <i>C_L</i>/<i>C_D</i> . In order to discuss the revealed <i>α</i> effects, we visualise the flow around the airfoils using the <i>Q</i> value, the helicity, streamlines' distribution around an airfoils at <i>α</i> = 0 – 24 deg., together with PIV analysis based on water-tank experiment.</p>