Mini-TED跨声速气动特性及其增升机理

通过求解二维可压Navier-Stokes方程，研究了NACA0012翼型加装微型后缘增升装置（mini-TED）后的跨声速流场特性，与Gurney flap （GF）对比分析了几何参数对mini-TED后方涡系及翼型气动特性的影响.将mini-TED的几何细节参数定义为弦向长度和有效高度，两者方向正交.在相同迎角下仅改变mini-TED的弦向长度，后缘涡系结构虽发生变化，但翼型气动力几乎没有影响；反之仅改变有效高度则后缘涡系和翼型气动力系数同时发生明显改变，且与同等高度下的GF气动系数相近.结果表明：有效高度是影响翼型气动特性的决定因素.有效高度改变了mini-TED后涡系的发生范围，而相对于整个翼型绕流，后缘涡系的大小是影响翼型流场最重要的因素，而涡系的微观结构和形态的改变影响相对很小.加装mini-TED后上表面激波位置后移、下表面激波强度削弱，从而翼型表面压力分布特性发生了改变.随有效高度增大，mini-TED诱导的涡系发生区域随之增大，引流作用增强，翼型升力系数、阻力系数和低头力矩系数提高，同时相同迎角下翼型的升阻比明显提高.

Aerodynamic characteristics and lift enhancement mechanism of mini-TED in transonic flow

By means of solving two dimensional and compressible Navier-Stokes equations, the transonic flow-field characteristics of NACA0012 airfoil equipped with mini trailing edge lift enhancement device (mini-TED) was investigated, and the influences of geometrical parameters on the vortices and aerodynamic characteristics of airfoil were analyzed and compared with the Gurney flap(GF). The two orthorhombic geometry detailed parameters were defined as chord-wise length and effective height to describe the geometric features. Only the chord-wise length changed at the same angle of attack, although the trailing edge vortices varied greatly, the aerodynamic characteristics of airfoil had little change. On the other hand, the trailing edge vortices and the aerodynamic characteristics of airfoil varied significantly with the effective height changed, and the aerodynamic characteristics were very close to the GF in the same condition of effective height. Result shows that the effective height plays a dominant role in affecting the aerodynamic characteristics of airfoil. Rather than the microstructure and shape, the size of the vortices is the main factor influencing the flow field of airfoil as this is mainly decided by the effective height. With the mini-TED, compared with the original airfoil, the shock wave on the upper surface of the airfoil moves backward and the strength of the lower shock wave is weakened, so the pressure coefficient of airfoil surface changes. With the increasing effective height, the induced vortices scope becomes larger, enhancing the drainage effect and increasing the lift coefficient, drag coefficient and nose-down pitching moment coefficient. The lift-drag ratio is improved at the same angle of attack as well.