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

(1)提出了一种利用超声速多元件空气动力学的高性能气动装置。利用计算流体动力学（CFD）对双翼机机翼进行了研究。这些机翼通过利用两个机翼元件之间的压力波之间的有利相互作用来实现几乎无阻力的性能。通过2005年和2006年的研究，设计出了一种性能最好的双翼翼型。它有足够的升力巡航速度为1.7马赫和升阻比（l/d）为21。这是世界上第一次证明升力双翼飞机可以具有如此高的l/d性能。在2007年，双翼机机翼已被研究，通过扩展设计的翼型三维设备。同时也证实了本项目开发的翼型/机翼设计系统对于二维和三维设计问题都能有效和准确地工作。(2)对亚音速流场多体问题进行了详细的CFD分析，模拟了马赫数为0.2时飞机的绕流场。该构型由机身、发动机短舱和机翼组成，机翼具有处于伸展状态的缝翼和襟翼。基本流动方程是雷诺平均的Navier-Stokes方程。缝翼与主翼、机翼与发动机短舱等之间存在着多种干扰，因此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学干扰。计算采用尽可能高密度的网格分布。目前，我们已经获得了可靠的定性数据。然而，对于详细的分析，目前的分辨率水平是不够的。需要发展先进的数值技术来分析分离流场、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.