Progress and prospects in sweeping jet heat transfer

Sweeping Jet Fluidic Oscillator (SJFO) is a functional device to generate self-excited unsteady oscillatory jets, based on the exact nature of flow instabilities within the device. On account of its inherent advantages, such as unique operation with self-excitation and self-sustainability, strong unsteady flow actuation with high sweep frequency and wide sweep fan angle, simple geometry with no moving parts, etc., SJFO is recognized as one of the promising potential candidates as applied to flow and heat transfer control practices, particularly for the aerospace community. During the past twenty years, vast efforts have been devoted to this issue, advancing the technological development and innovation application of the SJFOs. The current review mainly concentrates on the emerging interests of SJFOs in heat transfer applications, including sweeping jet impingement heat transfer, sweeping jet film cooling and sweeping jet composite cooling. First, a comprehensive overview regarding the recent advancement of sweeping jet heat transfer is provided. Then, from this overview, some general roles of sweeping jet impingement heat transfer and film cooling are presented and the research gaps are briefly addressed. Finally, an outlook on the challenges and future development of sweeping jet heat transfer is put forward to motivate further investigation in four aspects, such as, actively adjustable strategies for the sweeping jet frequency and fan angle, multi-parameter correlation mechanism and optimization of sweeping jets, integration innovation by combining the other enhanced schemes into sweeping jets, and a wide variety of composite cooling configurations by the use of sweeping jets.