Numerical Investigation on Flow Control of a Hypersonic Airfoil by Plasma Synthetic Jet

Abstract

Plasma synthetic jets (PSJs) have received widespread attention because of their rapid response capability. The use of PSJ shock and thermal effects for active flow control has been investigated in many recent studies. Through numerical simulation, this study found that the geometric position of a PSJ actuator on an airfoil surface is the key factor affecting flow control effects. Different geometric positions have different effects on the lift-drag characteristics of an airfoil, and the flow control mechanism has different components. The flow control mechanism can be divided into three types: the thermal effect, the coupling of the thermal effect and single shock, and the coupling of thermal effect and multiple-shock rebound. The concept of distance lplacement provides a reference for determining the geometric arrangement of a PSJ actuator. This study showed that in addition to improving the lift-drag characteristics of an airfoil by reducing drag, directly increasing lift is also a new choice. In addition, in a confirmatory experiment, the nanosecond pulse PSJ actuator pushed the bow shock in a Mach 5 flow; the longest distance was about 1% of the characteristic length of the airfoil. In this work, a new type of plasma actuator was used for flow control in hypersonic flow. The influence of the geometric position of the actuator on flow control and the corresponding flow control mechanisms were investigated. This work provide a reference for most work using actuators. For example, the geometric position of an actuator can be selected according to lplacement defined in this work and the parameters of the actuator can be set according to the parameter settings of the PSJA. For aerodynamics research, this work provides a new research idea for improving the aerodynamic performance of aircraft. If drag reduction is difficult to achieve, then increasing lift is also a feasible method. For research on plasma flow control, this work broadens its application to hypersonic flow and reveals that a plasma actuator has two flow control effects at the same time. PSJA conducts flow control through the impact effect of the diffracted wave and the mixing effect of the high-temperature cluster; this provides a reference for relevant personnel.