Drag reduction on the 25∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{\varvec{\circ }}$$\end{document} Ahmed body using a new zero-net-mass-flux flow control method

Periodic-forcing jets are applied to form a zero-net-mass-flux actuator for active flow control study on the 25∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$25^{\circ }$$\end{document} Ahmed body. Unlike traditional synthetic jet, this new proposed zero-net-mass-flux actuator has managed to divide the blowing phase and suction phase apart on different separation edges on the rear part of the body. Numerical simulation based on the large eddy simulation method is carried out on the near-wake flow to obtain both time-averaged and transient information of the flow field. The effects of the new actuators on the flow topology, the static pressure distribution and the process of the flow are analyzed to understand the mechanism of the drag reduction. Overcoming the drawbacks of the synthetic jet, our new zero-net-mass-flux actuator has successfully reduced the aerodynamic drag by a maximum of 25.5%.