A Study on Development of Airfoil Shape Toward Low Reynolds-Number Dependence of Aerodynamic Characteristics Under Low-Reynolds-Number-Flow Conditions

摘要

This paper investigates the airfoil aerodynamics under low Reynolds number conditions (O(10~4)). An airfoil shape is developed for a cross-sectional shape of a main wing of fixed-wing airplane on Mars. A Reynolds-number dependence of aerodynamic characteristics is one of important issues in the airfoil design for the main wing of Mar airplane. According to expected cruise flight conditions, chord-based Reynolds numbers are set to 20,000, 30,000, and 40,000, respectively, and the angle of attack changes from 0 degrees and 9 degrees. In this study, we perform two-and three-dimensional numerical simulations and experimental force and flow measurements in order to understand the relationship between the aerodynamic coefficients and flow structures around the airfoil. Time-and span-averaged aerodynamic force results are in a fair agreement with the experimental results and captures qualitative trend. Results also suggest that the proposed airfoil is better aerodynamic performances in comparison with those of SD7003 airfoil and Ishii airfoil at the Reynolds number of 20,000. Effects of Reynolds number on the airfoil aerodynamics are investigated and discussed.