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以布兹曼双层翼为基础,采用基于压力梯度自适应的非结构网格求解欧拉方程的计算流体力学(CFD)方法,计算分析了双层翼翼型的厚度和翼面间距对阻力特性的影响。在马赫数为1.7的情况下,由于激波的反射和干涉,超声速双层翼翼型的阻力系数仅为0.00189,为相同厚度菱形翼型的1/15。本文通过进一步的研究发现:减少翼型厚度对于双层翼翼型设计马赫数的阻力系数有一定的影响,且与超声速状态相比,厚度对于亚声速状态的阻力影响更大,厚度减少20%,亚声速状态的阻力系数减少可达60%以上;翼面间距对阻力特性的影响相对复杂,设计马赫数之前的阻力系数与翼面间距成反比,而设计马赫数之后的阻力系数与翼面间距成正比。在此基础上,基于激波的反射及干涉效应,提出了一种双设计状态的双层翼翼型,在最佳设计点之前,双层翼之间的激波/膨胀波会有两次反射,使翼型前后的压力基本相同,阻力系数出现一次下降。随着马赫数的增加马赫角减少,激波经过一次反射就能使翼型前后的压力基本相同,使翼型达到最佳设计状态。计算结果表明,双设计状态双层翼能够使双层翼翼型在两个设计点都具有较低的阻力系数。
Based on the Bouzeman double-decked wing, a computational fluid dynamics (CFD) method based on a pressure gradient adaptive unstructured grid to solve the Euler’s equation is adopted. The effects of thickness and airfoil spacing on the drag characteristics Impact. At a Mach number of 1.7, the drag coefficient of the supersonic double skin airfoil is only 0.00189 due to the shock reflection and interference, which is 1/15 of the diamond airfoil of the same thickness. In this paper, through further research, it is found that reducing the airfoil thickness has some influence on the drag coefficient of the Mach number of the double wing airfoil design, and the thickness has a greater impact on the sub-sonic resistance than the supersonic condition. The thickness is reduced by 20% The drag coefficient at subsonic speeds can be reduced by more than 60%. The influence of airfoil spacing on the drag characteristics is relatively complicated. The drag coefficient before the design Mach number is inversely proportional to the airfoil spacing. However, the drag coefficient after designing the Mach number is different from the airfoil spacing Is proportional. Based on this, based on the reflection and interference effects of shock wave, a double-decked wing model with double design conditions is proposed. Before the optimal design point, there will be two reflections , So that before and after the airfoil pressure is basically the same, a drag coefficient decreased. As the Mach number decreases, the Mach number decreases and the shock waves reflect at about one time will make the airfoil pressure basically the same, which will make the airfoil reach the optimal design state. The calculation results show that the dual-design wing with double design can make the double-wing design have a lower drag coefficient at both design points.