跨声速巡航态连续光滑偏转后缘翼型气动特性

Aerodynamic Characteristics of Morphing Airfoils with Continuous Smooth Trailing Edges at Transonic Cruise Condition

以连续光滑偏转后缘变弯度跨声速翼型为研究对象,对其开展了巡航状态绕流数值模拟,研究了其气动特性并与基本翼型和简单襟翼偏转后缘变弯度翼型的气动特性进行了比较。基本翼型采用RAE 2822超临界翼型;绕流数值模拟采用雷诺平均Navier-Stokes方法,通过与基本翼型试验数据比较,确认了数值模拟方法的准确性。研究发现,跨声速巡航状态下,连续光滑偏转后缘翼型能通过小偏转角变弯度来减小翼型的压阻及总阻力,从而可在巡航过程中升力系数变化条件下实时改善翼型气动特性;这种气动效益在简单襟翼偏转后缘翼型上也能达到同等程度甚至略有增大,表明从气动特性的角度而言跨声速巡航态小偏转角变弯度情形对变弯度方式的敏感性小于已有研究中关注的低速飞行大偏转角变弯度情形,因而跨声速巡航态需要更精细的变弯度方式设计。

Numerical simulation of transonic variable camber morphing airfoils with continuous smooth trailing edges is carried out,and its aerodynamic characteristics are compared with those of baseline airfoil and variable camber airfoils with plain flaps.The baseline airfoil is RAE 2822 supercritical airfoil;Reynolds-averaged Navier-Stokes method is adopted for numerical simulation of flow around airfoils,and the accuracy of numerical simulation method is validated by comparing with experimental data of baseline airfoil.It is found that variable camber morphing airfoils with continuous smooth trailing edges can reduce its pressure drag and total drag by varying camber with small deflection angle at transonic cruise condition,so that the aerodynamic characteristics of the airfoil can be improved in real time under the condition of variation of lift coefficient during the cruising process.This aerodynamic benefit can also be achieved at the same or even larger degree by variable camber airfoils with plain flaps,which demonstrates from the viewpoint of aerodynamics that the variable camber morphing at transonic condition with small deflection angle is less sensitive to methods of deflection than variable camber morphing at low-speed condition with large deflection angle in existing studies,and thus more sophisticated design for methods of morphing is needed at transonic cruise condition.