Open-loop flow control method was used to affect the development of a turbulent wake behind a D-shaped bluff body. Loud speakers were embedded inside the bluff body to produce two zero-net-mass- flux jets through 2 mm...Open-loop flow control method was used to affect the development of a turbulent wake behind a D-shaped bluff body. Loud speakers were embedded inside the bluff body to produce two zero-net-mass- flux jets through 2 mm-wide span-wise slots located along the upper and lower edges on the rear wall. The drag forces for different actuation amplitudes （Cμ, the ratio between the momentum of the actuating jets and the moment deficit caused by the bluff body） and frequencies （StA） were examined. The effects of the phase difference in the two jets （0 and π） were also studied. It was found that when Cμ was 0.1%, a drag reduction up to 5% was achieved when the velocities of the two jets varied in phase at a frequency of 5tA = 0.16. When the velocities of the two jets varied π out of phase, significant drag increase was observed.展开更多
基金supported by the National Basic Research Program(2014CB744100)State Key Laboratory of Aerodynamics(SKLA20130102)Dalian University of Technology(DUT14LK07)
文摘Open-loop flow control method was used to affect the development of a turbulent wake behind a D-shaped bluff body. Loud speakers were embedded inside the bluff body to produce two zero-net-mass- flux jets through 2 mm-wide span-wise slots located along the upper and lower edges on the rear wall. The drag forces for different actuation amplitudes （Cμ, the ratio between the momentum of the actuating jets and the moment deficit caused by the bluff body） and frequencies （StA） were examined. The effects of the phase difference in the two jets （0 and π） were also studied. It was found that when Cμ was 0.1%, a drag reduction up to 5% was achieved when the velocities of the two jets varied in phase at a frequency of 5tA = 0.16. When the velocities of the two jets varied π out of phase, significant drag increase was observed.
