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以增加升力、弱化激波为目的,采用计算流体力学的方法,开展了流场主动控制技术的研究。提出了内埋压电材料在上翼面引入周期性正弦振动形成附面层扰动这一主动控制方法。利用结构网格和相应的非定常流计算方法,对变形过程中的气动特性进行了数值仿真。分析了各种变形参数对升力特性的影响。以往的研究大多局限在二维翼型的数值仿真,本文将计算方法扩展到三维机翼模型,以进一步验证控制方法的有效性。研究表明,通过适当的参数优化,局部主动变形能够改善翼型背风区的气动特性,起到增升减阻的作用。低马赫数下,非对称翼型升力系数可提高15%;阻力系数减小16%;高马赫数下,通过控制使激波后移,对称翼型升力系数可提高17%。与传统机翼相比,这种自适应机翼负面效应小,不破坏机翼的结构,可以满足多种飞行状态下的气动需要。
In order to increase the lift and weaken the shock wave, a computational fluid dynamics (CFD) method is used to study the active control of flow field. An active control method was proposed in which embedded piezoelectric material introduced periodic sinusoidal vibration on the upper airfoil to form a surface perturbation. The numerical simulation of the aerodynamic characteristics in the deformation process is carried out by using the structural grid and the corresponding unsteady flow calculation method. The influence of various deformation parameters on the lift characteristics is analyzed. In the past, most of the research was limited to the numerical simulation of two-dimensional airfoil. In this paper, the calculation method was extended to the three-dimensional wing model to further verify the effectiveness of the control method. The research shows that by proper parameter optimization, local active deformation can improve aerodynamic characteristics of airfoil leeward zone and increase the drag reduction effect. At low Mach numbers, the lift coefficient for asymmetric airfoils can be increased by 15% and the drag coefficient can be reduced by 16%. The lift coefficient for symmetric airfoils can be increased by 17% at high Mach numbers by moving the shock backward. Compared with the traditional wing, the self-adaptive wing has the advantages of small negative effect and does not destroy the structure of the wing to meet the aerodynamic needs under various flight conditions.