Analysis of the Near Field in a Plasma-Actuator-Controlled Supersonic Jet

作者：Gaitonde D V

来源：Journal of Propulsion and Power, 2012, 28(2): 281-292.

DOI：10.2514/1.b34289

Simulations are employed to examine the near field of a Mach 1.3 jet subjected to eight plasma actuators mounted on the periphery of the nozzle exit. The simulations are validated by comparing several quantities with experiments, including mean and fluctuating streamwise velocities, as well as visualizations of coherent features. The generation, evolution, and breakdown of coherent structures with first (m = 1), second (m = 2), and third On = 3) azimuthal mode excitation are described and set in the context of previous simulations with axisymmetric and mixed modes at the most amplified jet column mode (Strouhal number 0.3). Hair-pin-like vortices, observed in instantaneous, as well as phase-averaged data, are noted as key building blocks in the evolution process. The tips/heads arise in the outer region of the jet shear layer and legs extend forward, slightly inclined in the direction of the jet axis where the velocity is higher. The interaction of these structures through self and mutual induction with those generated by adjacent actuators, or later by the same actuator, yields a rich variety of features depending on excitation mode. In the second part of the paper, the effect of Strouhal number on the near field is explored with m = 0 and In = I excitation. The results show that, at higher frequencies, large structure formation is inhibited and peak sound pressure level amplitudes diminish in a manner consistent with experimental results.

• 出版日期2012-4