遷音速流れ場の相似則と二次元複葉翼の数値解析結果への適用

抄録

General transonic similarity rules and the similarity rules around Mach 1 on the aerodynamic coefficients of quasi-cylindrical bodies including biplanes are developed to extract the characteristic dimensionless quantities for flowfields around transonic biplanes. To verify the similarity rules, numerical simulations of biplane airfoils are performed by solving the Euler equations. Two RAE2822 airfoils are used in the simulations as typical transonic airfoils. The results of the numerical simulations show good agreement with the similarity rules even if there is shock wave interaction between the wings. Furthermore, shock wave patterns are the same when the values of similarity parameters are the same. These results illustrates the potential of the similarity rules for searching wide range of design space and classifying the shock wave patterns. Applying similarity rules to biplane airfoils in transonic flows, the relationship between the distance of the wings in the uniform flow direction and aerodynamic coefficients are numerically investigated. The result show that the lift-to-drag ratio is large when the upper wing is placed upstream of the lower wing.