Active Control for Wall Drag Reduction: Methods, Mechanisms and Performance

Active reducing the skin friction drag of vehicles (such as missiles, rockets, aircraft, high-speed train, submarines, etc.) during the navigation process can improve the respond speed effectively, save the energy consumption and increase the endurance time. As lots of active drag reduction methods were proposed for different applications, a review article is urgently needed to guide researchers to choose suitable methods for their pre-research. In this review, the generation mechanisms of skin friction drag under the action of disturbing the turbulent boundary layer are discussed, and the main active drag reduction methods are summarized. According to the actuation modes, we divided the active drag reduction methods into: drag reduction based on wall motion; drag reduction based on volume force control; drag reduction based on wall deformation and drag reduction based on micro vibration generated by piezoelectric actuator. The development status, drag reduction mechanisms, typical structures and drag reduction performance of each active drag reduction method are discussed and summarized in this work, which can provide preliminary research references for those who are engaged in the research of active wall drag reduction.