低レイノルズ数領域における石井翼型上面形状変更が及ぼす空力特性への影響

摘要

電子部品の小型化などの科学技術の進歩により，無人飛行機(UAV： Unmanned Air Vehicles)や超小型飛行機(MAV：MicroAirVehicles)の研究開発が進められてきた.このUAVやMAVは，災害現場での物資輸送や，機動性の高い広範囲にわたる観測•監視システムとして，人が直接入り込むには難しい危険地域などにおける活躍が期待されている.また，現在火星探査ミッションMELOS1内での使用も検討されており，近年非常に注目を集めている.これらのUAVやMAVは機体が小さく，低速での飛行であるため，対象レイノルズ数(Re数)は10~4～10~5程度の低Re数領域である.そのため，UAVやMAVの空力性能向上のためには，低Re数領域で性能が優れた翼型開発が求められている.%For the investigation of UAV and MAV, development of wing section which has high aerodynamics performance at the low Reynolds numbers region is required. In addition, the aerodynamic characteristics of the airroil are influenced by the flow separation which is affected by the wing section configuration. In this study, the influences of upper surface configuration on the aerodynamic characteristics of the Ishii airfoil at the Reynolds number of 50,000 are experimentally investigated. The results demonstrated the laminar separation near the trailing edge whose configuration was resembled to that of NACA0012 airfoil. The lift coefficients, which becomes negative values in the NACA0012 airfoil case because of the laminar separation at the trailing edge, increases almost liner with the increase in the angle of attack. Turbulent region which is increased by the formation of the laminar separation bubble near the leading edge increases drag coefficients. The desirable upper surface configuration of wing section maintains the re-attachment of the laminar separated flow near the trailing edge at high angle of attack condition.