EFFECT OF THERMAL ACTUATOR ON VORTEX CHARACTERISTICS IN SUPERSONIC SHEAR LAYER
Recent experiments show that localized arc filament plasma actuators have been successfully applied in mixing enhancement of shear layer.The plasma actuator(also called thermal actuator)can make difference in changing the vortex characteristics in supersonic shear layer,such as frequency and intensity,therefore the formation of supersonic shear layer and noise source is expected to be affected by using thermal actuator.Large eddy simulation(LES)is applied to simulate a three-dimensional planar free shear layer at Mach 1.3 supersonic flow in this study.A 205×140× 49 grid is used for the analysis of flow structure.It is found that the fundamental mechanism of the thermal actuators affecting the shear layer is the thermal effect of the actuators,although how the thermal effect couples with the shear layer is unclear yet.In this study the thermal actuator is re-accessed in a groove slightly upstream the origin of the shear layer,causing elevated local heating.Here two electric poles as one group protected by one groove produce electric arc to heat the fluid inside the groove,which affects the initial condition of the shear layer.The groove is required to form a low velocity region for plasma fluid to reach steady status and retain high temperature.Results show that vortices mix together several times before they reach another stage in which the pairing phenomenon occurs,and the pressure fluctuation frequency decreases quickly downstream.The growth rate of the velocity boundary in the low-speed region is larger than that in the high-speed region in all cases.Cases with heat sources have larger growth rate of both velocity boundaries,higher surface-averaged turbulent kinetic energy and vorticity than those in the baseline case.The effect of the actuator decays downstream and increasing of the power of actuators can not change this trend.However,as the power increases,the dominant frequency increases,but the amplitude on this frequency decrease ; it is also observed that the effect of the thermal actuators replaces single high peak in the frequency spectrum with several lower peaks with higher dominant frequency.
Thermal actuator Shear layer Supersonic flow Large eddy simulation
Ke Lin Hong Yan
Northwestern Polytechnical University,Xian,710072,China Collaborative Innovation Center for Advanced Aero-Engine,Beijing,100191,China
国际会议
The 5th International Symposium on Jet Propulsion and Power Engineering(第五届喷气推进与动力工程国际会议)
北京
英文
1-14
2014-09-15（万方平台首次上网日期，不代表论文的发表时间）