Theoretical study on the aerodynamic effect of mutual interaction in multi-body problems

(1)提出了一种利用超音速多元气动力的高性能气动装置。利用计算流体力学(CFD)对双翼进行了研究。这些机翼利用两个机翼元件之间的压力波之间的良好相互作用，实现了几乎无阻力的性能。通过2005年和2006年的研究，设计出了一种性能最好的双翼型。它有足够的升力进行巡航，航速为1.7马赫，升阻比(L/d)为21。这是世界上第一次展示一架抬起的双翼飞机能有如此高的L/d性能。2007年，通过将所设计的翼型扩展到三维装置，对双翼进行了研究。验证了本课题开发的翼型/机翼设计系统对于二维和三维设计问题都是高效、准确的。(2)对亚音速流场中的多体问题进行了详细的CFD分析，模拟了马赫数为0.2的飞机绕流。该布局由机身、引擎舱和一个机翼组成，机翼在伸展状态下具有板条和襟翼。基本流动方程为雷诺平均的N-S方程。板条与主翼、机翼与吊舱等之间存在着多次相互作用，流动现象必然是复杂的。我们打算获得有用的数据来模拟空气动力相互作用。计算使用了尽可能高密度的网格分布。目前，从质量上讲，我们已经获得了可靠的数据。然而，对于详细的分析，目前的解决水平是不够的。需要设计先进的数值技术来分析分离的流场、旋涡和自由剪切层。

(1) A high performance aerodynamic device which utilizes supersonic multi element aerodynamics has been proposed. Biplane wings have been researched using computational fluid dynamics (CFD). Those wings realize almost drag-less performance by utilizing favorable interaction between pressure waves of two wing elements. Through the research in 2005 and 2006 years, one of the best biplane airfoil was designed. It has sufficient lift for the cruise with the speed of Mach 1.7 and the lift-drag ratio (l/d) is 21. This is the first time in the world to show that a lifted biplane can have such a high l/d performance. In 2007, biplane wings has been investigated by extending the designed airfoil to a three dimensional device. It has been also confirmed that an airfoil/wing design system, which has been developed in this project, works efficiently and accurately for the both of 2D and 3D design problems.(2) Detailed CFD analysis about multi body problems in a subsonic flow-field has been conducted A flow-field around aircraft has been simulated at the Mach number of 0.2. The configuration consists of a fuselage, an engine nacelle and a wing which has a slat and a flap in extended condition. Basic flow equations are Reynolds averaged Navier-Stokes ones. There occur many interactions between a slat and a main-wing, a wing and a nacelle etc. Therefore, the flow phenomena must be complicated. we intended to obtain useful data to model aerodynamic interaction. The computations have been conducted using grid distribution as high density as possible. At the present, qualitatively we have obtained reliable data. However, for the detailed analysis, the current resolution level is not sufficient. It is needed to devise advanced numerical techniques to analyze separated flow-fields, vortices and free sheer layers.