Preliminary study on pulsed jets with three-dimensional effects for flow separation control in a compressor blade

In this study, three-dimensional (3D) effects were created by adjusting the structure of traditional 2D pulsed jets and investigated experimentally and numerically. Experiments with a compressor blade controlled by the pulsed jets with 3D effects showed that the control performance could be optimized when the reduced frequency equals one and the space angle equals zero. In addition, the optimal control performance of 3D pulsed jets is better than that of 2D pulsed jets. Numerical simulations of compressor cascades controlled by 2D and 3D pulsed jets were also performed to reveal the mechanism of the space angle effect and explain the advantage of 3D pulsed jets. The simulations indicated that costing the same momentum coefficient, 3D pulsed jets could reduce the relative total pressure loss coefficient by about 50% compared with that of the 2D pulsed jet. Further analysis of the numerical results showed that 2D and 3D pulsed jets share the same mechanism of utilizing flow instability and spanwise separation vortices. However, 3D pulsed jets have the ability to generate additional streamwise vortices (like vortex generators), which contribute to more momentum transfer to the separation zone and better control performance than 2D pulsed jets. (C) 2021 Elsevier Masson SAS. All rights reserved.