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.

To address deeper understandings about the aero-thermal performance of an integrating infrared suppressor under more realistic situations, a numerical investigation is motivated in the current study, concerning the effects of forward-flight speed on exhaust plume flow and infrared radiation of the Infrared Suppressor-integrating (IRS-integrating) helicopter, wherein the forward-flight speed is changed from 0 m/s (hover state) to 100 m/s, while both the engine exhaust parameters and the main-rotor operation parameters remains unchanged during different forward-flight velocities. The results show that the interaction between forward-flight flow and downwash flow alters the exhaust plume development and the internal flow inside the IRS-integrating rear fuselage more complicatedly, tightly dependent on the forward-flight speed. Of particular concern is the situation where the forward-flight flow has nearly the same level as the downwash flow, the hot mixing flow could possibly interacts with the helicopter rear fuselage to play a local heating effect. With the increase of forward-flight speed, the ejection coefficient is generally increased and the average exhaust temperature of mixing flow is decreased, leading to a reduction of the infrared radiation intensity of exhaust plume in 3–5 μm band. However, the influence of forward-flight speed on the overall infrared radiation intensity of IRS-integrating helicopter is conjectured not monotonous due to the complicated interaction between forward-flight flow and downwash flow. Under high-speed forward-flight states, the overall infrared radiation intensity of the IRS-integrating helicopter in 3–5 μm band is reduced with the increase of forward-flight speed. With respect to 3–5 μm band, the forward-flight speed has little effect on the infrared radiation in 8–14 μm band.