Boundary Layer Characteristics Research Articles

An anomalous method of using a camera in determining the velocity distribution within a boundary layer

The current study proposes a cost-effective technique wherein a camera can be used anomalously in tandem with the working of a pitot tube in determining the velocity distribution within a boundary layer. The technique involves the traversal of a pitot tube at a uniform velocity inside the width of boundary layer and simultaneously imaging the change in meniscus location of liquid column in the corresponding manometer, inside a wind tunnel set-up. The study aims in establishing a relation between the traversal velocity and the free stream velocity. The proposed approach holds the advantage of providing velocity values at equally spaced locations within the boundary layer, with the number of values depending on the velocity of retraction (traversal away from the surface) as well as the frame rate of recording. Experiments were performed at different combinations of retraction velocity (Vr) and Fan Speed for establishing the method. An optimum velocity at which the pitot tube should be retracted was determined based on convergence of trend of the variation in instantaneous meniscus locations to a standard reference trend. Results show that dimensionless optimum velocity (V¯o) defined as the optimum ratio between tunnel velocity (Ut) and Vr is related to the Fan Speed (FS) by V¯o∝ FS0.6. Additionally, with regard to the manual traversing performed, the probability density function plots show that traversing manually at V¯≫V¯o introduces higher non-uniformity in the results, thereby preferable to perform the traversal closer to values of V¯o. Using the results obtained from the developed imaging technique, the velocity variation within the boundary layer was studied. The technique was successful in precisely locating the prominent points inside a boundary layer for a particular flow condition. Finally as a case study, the imaging approach was also utilized in determining the effect of roughness change across the seam of a cricket ball on its aerodynamics. This case study also shows that the technique is successful in obtaining the flow characteristics of a general boundary layer as well as a flow separation case.

Influence of curvature distribution smoothing on the reduction of aerofoil self-noise

PurposeThis paper aims to investigate the influence of smooth curvature distributions on the self-noise of a low Reynolds number aerofoil and to unveil the flow mechanisms in the phenomenon.Design/methodology/approachIn this paper, large Eddy simulation (LES) approach was performed to investigate the unsteady aerodynamic performance of both the original aerofoil E387 and the redesigned aerofoil A7 in a time-dependent study of boundary layer characteristics at Reynolds number 100,000 and angle of attack (AoA) 4-degree. The aerofoil A7 is redesigned from E387 by removing the irregularities in the surface curvature distributions and keeping a nearly identical geometry. Flow vorticity magnitude of both aerofoils, along with the spectra of the vertical fluctuating velocity component and noise level, are analysed to demonstrate the bubble flapping process near the trailing edge (TE) and the vortex shedding phenomenon.FindingsThis paper provides quantitative insights about how the flapping process of the laminar separation bubble (LSB) within the boundary layer near the TE affects the aerofoil self-noise. It is found that the aerofoil A7 with smooth curvature distributions presents a 10% smaller LSB compared to the aerofoil E387 at Reynolds number 100,000 and AoA 4-degree. The LES results also suggest that curvature distribution smoothing leads to a 6.5% reduction in overall broadband noise level.Originality/valueThis paper fulfils an identified need to reveal the unknown flow structure and the boundary layer characteristics that resulted in the self-noise reduction phenomenon yielded by curvature distribution smoothing.

A Quick Simulation Method for Aero-Optical Effects Based on a Density Proxy Model.

Aero-optical effects caused by high-speed flow fields will interfere with the transmission of starlight, reduce the accuracy of optical sensors, and affect the application of celestial navigation on hypersonic vehicles. At present, the research of aero-optical effects relies heavily on the flow field simulation of computational fluid dynamics (CFD), which requires a great deal of computing resources and time, and cannot satisfy the demand of the rapid analysis of aero-optical effects in the engineering design stage. Therefore, a quick simulation method for aero-optical effects based on a density proxy model (DP-AOQS) is proposed in this paper. A proxy model of the turbulent density field is designed to replace the density field in the CFD simulation, and the proxy model is parametrically calibrated to simulate the optical characteristics of the turbulent boundary layer (TBL) in the external flow field of the optical window. The performance of DP-AOQS in the visible light band is verified from the perspectives of density field distribution, optical path difference (OPD), and fuzzy star map. The simulation results show that the method can quickly provide the distortion results of aero-optical effects in different flight conditions on the premise of ensuring the simulation accuracy. The research in this paper provides a new analytical method for the study of aero-optical effects.

Performance of an Improved TKE-Based Eddy-Diffusivity Mass-Flux (EDMF) PBL Scheme in 2021 Hurricane Forecasts from the Hurricane Analysis and Forecast System

Abstract Continuous development and evaluation of planetary boundary layer (PBL) parameterizations in hurricane conditions are crucial for improving tropical cyclone (TC) forecasts. A turbulence kinetic energy (TKE)-based eddy-diffusivity mass-flux (EDMF-TKE) PBL scheme, implemented in NOAA’s Hurricane Analysis and Forecast System (HAFS), was recently improved in hurricane conditions using large-eddy simulations. This study evaluates the performance of HAFS TC forecasts with the original (experiment HAFA) and modified EDMF-TKE (experiment HAFY) based on a large sample of cases during the 2021 North Atlantic hurricane season. Results indicate that intensity and structure forecast skill was better overall in HAFY than in HAFA, including during rapid intensification. Composite analyses demonstrate that HAFY produces shallower and stronger boundary layer inflow, especially within 1–3 times the radius of maximum wind (RMW). Stronger inflow and more moisture in the boundary layer contribute to stronger moisture convergence near the RMW. These boundary layer characteristics are consistent with stronger, deeper, and more compact TC vortices in HAFY than in HAFA. Nevertheless, track skill in HAFY is slightly reduced, which is in part attributable to the cross-track error from a few early cycles of Hurricane Henri that exhibited ∼400 n mi (1 n mi = 1.852 km) track error at longer lead times. Sensitivity experiments based on HAFY demonstrate that turning off cumulus schemes notably reduces the track errors of Henri while turning off the deep cumulus scheme reduces the intensity errors. This finding hints at the necessity of unifying the mass fluxes in PBL and cumulus schemes in future model physics development.

Downstream influence of turbulent flow past vortex generators

Abstract Vortex generators (VGs) are typically positioned upstream of a boundary layer separation region. Their effectiveness depends on incoming flow conditions (Mach number, Reynolds number, and boundary layer characteristics), geometrical configuration (vane or ramp, height, width, and angle of incidence), and spacing. Device-induced vortices and following decay allow VGs to be used as a passive control device. This study uses pressure-sensitive paint to determine the global surface pressure pattern for a flat plate flow in the presence of VGs (counter-rotating vanes, co-rotating vanes and ramps). The freestream Mach number is 0.64 and 0.83. The ratio between the height of the VGs and the incoming boundary layer thickness is 0.2, 0.5, and 1.0. The standard deviation in the spanwise pressure in the streamwise direction is used to determine the downstream influence of turbulent flow past VGs. Increasing the height of VGs causes device-induced vortices to propagate farther downstream.

The NCEP and ERA-Interim reanalysis temperature and humidity errors and their relationships with atmospheric boundary layer in the Tibetan Plateau

The lack of sounding observations in the western Tibetan Plateau (TP), the highest terrain in the world, has resulted in few efforts to evaluate the quality of the atmospheric reanalysis results in this region. Using the sounding observations from the Third Tibetan Plateau Atmospheric Scientific Experiment during 2013–2015, the NCEP and ERA-Interim reanalysis temperature and humidity fields in the TP are evaluated and the characteristics of the reanalysis Atmospheric Boundary Layer (ABL) height are utilized to explain the reasons for the differences in temperature and humidity between the western and eastern TP. The results show that the NCEP and ERA-Interim reanalysis temperature and humidity products generally have larger errors at low level (such as 500 hPa) in the western TP (WTP) than in the eastern one (ETP) at 12:00 UTC. However, this difference is small at 00:00 UTC. Further analysis reveals that the temporal and spatial variations of temperature and humidity errors at low level are closely associated with the differences in the terrain and ABL between the western and eastern TP. In the early morning when the ABL height is low over the TP, the 500 hPa pressure level in both the WTP and ETP is significantly above the top of ABL, with weak spatial variations of temperature and humidity errors. However, in the late afternoon when there is a larger increase in ABL height over the WTP than over the ETP, the 500 hPa pressure level is located inside the ABL in the WTP and is still above the ABL in the ETP, which causes significant regional differences in these errors.

Investigation of wind characteristics of typhoon boundary layer through field experiments and CFD simulations

High-resolution observations of typhoon boundary layer above 100 m are rare as traditional wind towers are generally below 100 m, which limits the study of typhoon boundary layer and engineering applications such as wind-resistant design of tall buildings and wind turbines in typhoon-prone regions. In this study, boundary layer winds of super typhoon Lekima (2019) are observed, simulated and analyzed. Together with traditional wind tower, Doppler wind lidar is utilized for observations of typhoon boundary layer in order to obtain measured data above 100 m. Besides, Computational Fluid Dynamics (CFD) simulation based on Large Eddy Simulation (LES) method is conducted to further investigate the impact of complex terrain on the near-surface wind characteristics. The results show that the power law fits the mean wind speed profile well below 100 m. However, before and after the typhoon lands, a local reverse or low-level jet occurs in the mean wind speed profile at the height of 100–300 m, which cannot be depicted by the power law. Meanwhile, the turbulence intensity increases with height and experiences larger fluctuations. In addition, there is a significant negative correlation between the ground elevation and power exponents of the fitted mean wind speed profiles. This study provides useful information to better understand wind characteristics of the typhoon boundary layer.

Long-term planetary boundary layer features and associated PM2.5 pollution anomalies in Beijing during the past 40 years

Long-term planetary boundary layer features and associated PM2.5 pollution anomalies in Beijing during the past 40 years

Convective Heat Transfer Coefficient of Insulation Paper–Oil Contact Surface of Transformer Vertical Oil Channel

Insulation paper is the primary inter-turn insulation material for transformer windings. However, insulation paper is a poor conductor of heat and seriously impacts the natural convective heat dissipation in the winding oil channels. In order to study the convective heat transfer performance of the transformer vertical oil channel, the heat transfer characteristics of the two-dimensional boundary layer of the insulation paper–oil contact surface were analysed, and a characteristic number equation with a roughness correction factor was established. Based on the similarity principle and modelling theory, an experimental apparatus was designed to determine the convective heat transfer coefficient of the insulation paper–oil contact surface. Coefficients were obtained for different qualitative temperatures and characteristic lengths. Parametric fitting of the experimental data was carried out to obtain the correction factors. The results show that the natural convective heat transfer coefficient h of the insulation paper–oil contact surface is positively and linearly related to qualitative temperature and inversely related to characteristic length. For temperatures of 312.9 K to 328.1 K and characteristic lengths of 3 cm, h ranges from 116.15 to 144.38 W/(m2 · K). For temperatures of 319.0 K to 337.9 K and lengths of 6 cm, h ranges from 103.79 to 131.14 W/(m2 · K). The correction factor of the characteristic equation coefficient is 1.067. The maximum deviation of h calculated with a coefficient of 0.63 and an exponent of 0.25 is 5.93%. The results are essential for modelling the transformer space thermal circuit and solving the hot-spot temperature problem.

Drag reduction of turbulent boundary layer over sawtooth riblet surface with superhydrophobic coat

The application of drag reduction tech holds great significance to energy saving. To achieve better drag reduction, we investigated the flow characteristics of the turbulent boundary layer (TBL) over a composite surface made of sawtooth riblets with superhydrophobic coat (rib&SHS), a superhydrophobic surface (SHS), and a smooth surface using particle image velocimetry. The results showed that the drag reduction rate of the composite surface was higher than that of the superhydrophobic surface at the same Reynolds number. When the Reynolds number reached 2015, the drag reduction effect of SHS was almost ineffective (drag reduction was only 1.2%), whereas rib&SHS maintained satisfactory results (drag reduction was 20.2%). By proper orthogonal decomposition (POD), the second-order POD mode showed the tilt angles of the interface of Q2 and Q4 events inside the TBL over rib&SHS, and SHS were reduced compared with the smooth surface in the drag reduction cases. With drag reduction of rib&SHS and SHS, the hairpin vortexes were lifted away from the wall and the distances of vortexes within hairpin vortex packets decreased. Compared with SHS, rib&SHS had a greater effect on hairpin vortexes and hairpin vortex packets because the riblets made the Q2 events of rib&SHS weaker than that of SHS. So, the rib&SHS has a higher drag reduction rate and a larger drag reduction Reynolds number range than the SHS. It can be used to guide the drag reduction design of underwater vehicles.

New method for calculating heat transfer in unsteady MHD mixed boundary-layers with radiative and generation heat over a cylinder

This paper is devoted to the analysis of an unsteady 2-D MHD dynamic and thermal boundary-layer over a horizontal cylinder in mixed convection, in the presence of suction/injection, heat source/sink, and heat radiation fluid electrical conductivity is constant. The system of MHD equations of dynamic and temperature boundary-layer, which describe complex non-auto model problems, has been solved by a new approach. New variables and sets of parameters were introduced and transformed equations were obtained, in which the influence of the magnitude Z was explicitly retained. In order to close the system of equations, to the equations of the boundary-layers momentum equation was added. The solution of the obtained system of non-linear differential equations was performed numerically using the finite difference method, with the simultaneous application of the iteration method. By replacing the derivatives in the system of equations with the corresponding relations of finite differences, a system of linear derivative algebraic equations is obtained, which is solved by the three-diagonal method. As a concrete example of the introduced method, the effects of heat transfer in the MHD boundary-layers were considered, in the case of mixed convention, over a horizontal circular cylinder. The boundary conditions for temperature are defined by linear functions of longitudinal co-ordinates and time. Numerical results for different Eckart, Schmidt, and expanded Prandtl numbers and values: magnetic, dynamic, thermal parameters, temperature, and buoyancy parameters were obtained and presented. The obtained results were analyzed through the diagrams of changes in velocity and temperature and the diagrams of integral and differential characteristics of boundary-layers and the corresponding conclusions were given.

The effect of mixing and heat transfer on regression rate of TAGN-based fuel in a segregated AP/TAGN solid motor

The effect of mixing and heat transfer on regression rate of TAGN-based fuel of a segregated AP/TAGN solid motor is studied in the present study. A regression rate model of TAGN-based fuel under coupled combustion is developed and validated based on detailed reaction mechanism. The two-dimensional mixing characteristics in boundary layer and the effect on regression rate of TAGN-based fuel are analyzed in detail. The simulation results show that the increase of initial temperature of oxidizer gas leads to better mixing in the axial direction and higher temperature of burning surface. However, the mass concentration of O2 decreases greatly due to the increasing consumption by primary combustion reactions of AP-derived gaseous species. Therefore, the regression rate of burning surface decreases slightly. With inflow Mach number increasing from 0.32 to 0.75, mixing in the boundary layer is greatly enhanced. Therefore, both the temperature and regression rate increase with inflow Mach number. As pressure increases from 4 MPa to 10 MPa, the primary reactions of AP-derived gas species are also enhanced. Therefore, the mass concentration of O2 decreases rapidly, which leads to oxygen-lean combustion in the combustion chamber. Therefore, the temperature of burning surface decreases while the regression hardly varies despite of the better mixing near the burning surface at high pressure. The results show that the coupled combustion reactions between inflow oxidizer gas and fuel gas mainly occur in a narrow belt-like region of the boundary layer. The results show that the regression rate of solid fuel in the segregated solid motor is controlled by the competition between primary combustion and coupled combustion.

Wind characteristics in typhoon boundary layer at coastal areas observed via a Lidar profiler

Information about typhoon wind characteristics provides a basis and is a prerequisite for conducting anti-typhoon studies and practices. Despite the great efforts and active exploration made in the field of typhoon measurements using various equipment over the past decades, how to effectively obtain both the mean and fluctuating components of typhoon wind especially within the atmospheric boundary layer around the inner region of the storm still remains as a challenge. In recent years, Lidar wind profilers have been attracting increasing attention and showing great promise owing to their advantages, such as wide detection range, high sampling frequency, handiness, and flexible layout. However, the results for turbulent wind components using Lidar wind profilers tend to be biased due to the intrinsic spatial average in remote sensing detection. In view of the above, this paper explores the use of the Lidar wind profiler to conduct legitimate measurements of typhoon averages and fluctuating wind field characteristics. Firstly, wind field measurements in the inner regions of two typhoons were successfully captured during their passage with the flexible deployment of equipment in coastal areas. Based on the data obtained, the mean wind field characteristics of the typhoons were examined during different transitional stages and under different exposure conditions, with a focus on the influence of inner boundary layer on the vertical wind speed profile and its key parameters, such as surface roughness and zero-plane displacement. A method based on a wind spectrum model is proposed to correct the typical fluctuating wind field parameters, which include turbulence integral length scale, turbulence intensity, and gust factor. The difference between these wind turbulence parameters before and after the correction was significant, but the corrected results were in better agreement with similar existing results, reflecting the necessity and validity of the correction work. The presented results are expected to be helpful for further understanding of the wind characteristics in the middle and upper portions of typhoon boundary layer, and contribute to the development of using Lidar profiler for observing wind turbulence.

Active Drag Reduction for the Wall of Microunderwater Vehicles by Piezoelectric Actuated Drag Reducer

The driving performance and endurance mileage of microunderwater vehicle can be improved by reducing the wall friction drag. The existing underwater drag reducers can achieve good drag reduction performance, but they are not suitable for microunderwater vehicle due to the large structure size and the high energy consumption. An active drag reducer, which is driven by piezoelectric actuator and can be embedded into the outer wall of microunderwater vehicle hardly changing the streamline structure and structural strength of the wall, is proposed. The active drag reduction on demand and effective energy saving can be realized by combining with the motion monitoring system of the underwater vehicle. The drag reduction mechanism of the proposed drag reducer driven by piezoelectric actuator is discussed. The influences of single parameter and comprehensive effect of parameters on the characteristics of the near-wall turbulent boundary layer are obtained, and the control methods of drag reduction performance for meeting different requirements are proposed. The simulation and experimental results show that the proposed microdrag reducer can effectively reduce the frictional and total drag, and can achieve positive energy saving. The drag reduction rate of 37.82% can be achieved with the excitation amplitude of 150 V and the operating frequency of 1500 Hz. This article can provide an important reference for the research of active drag reduction of microunderwater vehicle.

On the acoustic emission characteristics of airfoils with different trailing edge configurations

The present study experimentally and numerically investigates the flow past flat plates and NACA0012 airfoils with the different trailing edge (i.e., blunt, sharp, and rounded) and both end-rounded configurations on the far-field acoustic emissions and complex flow phenomena to determine the best edge geometry for low noise. The studies are conducted for various jet speeds of 20, 30, and 40 m/s (chordwise Reynolds numbers of 1.812 × 105, 2.72 ×105, and 3.62 ×105). It is observed that all the edge-modified flat plates show the highest directivity at an emission angle of 60° for all jet velocities studied. The comparison of power directivities between realistic and flat plate airfoils reveals that the realistic airfoils radiate lower acoustic emissions as compared to flat plate airfoils, albeit they show a common feature of downstream directivity. In general, the far-field acoustic emissions of both end-rounded plates are observed to be lower as compared to blunt, sharp, and rounded trailing edge geometries. The leading edge modification is also observed to reduce airfoil self-noise. The likely reason for the lower far-field acoustic emissions provided by both end-rounded trailing edged foils is due to the modification in the boundary layer characteristics owing to the presence of smooth flow around the rounded leading edge as well as reduced vortex strength as compared to the other foil geometries. Thus, the present study demonstrates that passive modifications of leading edge profiles are essential along with trailing edge for achieving lower acoustic emissions and higher noise reductions.

Hypersonic Boundary-Layer Disturbances on a Cooled, Slender Cone at Mach 6

This paper presents an experimental study of the effect of wall cooling on the boundary-layer structures of a sharp-nosed, 5° half-angle cone in Mach 6 flow. An experimental methodology was developed that allowed quantitative measurements of second-mode disturbance growth over a range of wall-temperature ratios from without modifying the freestream disturbance environment. The cooling system comprised probe cooling, liquid nitrogen injection, and thermal insulation. The model temperature was monitored before each run, with thermocouples mounted at the base and nosetip piece agreeing within 3.3 K. Calibrated schlieren provided global and time-resolved measurements of the boundary-layer features at a freestream unit Reynolds number of . An increase in wall-cooling level was associated with a shrinking of the boundary layer and a lowering of wavepacket structure angle at the wall. Despite some outlying results, an overall trend of increasing disturbance frequency with decreasing surface temperature was observed; additionally, cooling increased the spectral amplitude and growth rate of second-mode disturbances, pushing the point of saturation upstream.

Mesoscale Variability of Surface Ducts During Santa Ana Wind Episodes

AbstractMesoscale variability of the marine boundary layer characteristics and the corresponding radio wave ducting conditions over the Southern California Bight (SCB) during three Santa Ana wind events have been examined based on the analysis of field observations and diagnosis of mesoscale model simulations. Under the influence of a dry and the stably stratified airflow from inland, a shallow moist internal boundary layer (MIBL) develops over the coastal waters. The MIBL consists of a thin well‐mixed moist layer capped by an inversion layer where the specific humidity decreases with height sharply. Accordingly, a surface duct (SD) is virtually ubiquitous with its depth compared with the MIBL depth. The wind direction and the SD characteristics exhibit diurnal variations over the SCB area associated with land and sea breezes. In addition, the MIBL interacts with the coastal topography, Channel Islands, and sea surface temperature gradients, resulting in spatial mesoscale variabilities in SD characteristics. Specifically, the SD height and strength grow with the offshore distance owing to the surface latent heat flux over sea, and in the meantime, exhibit substantial along‐shore variations. The shallow MIBL tends to split and flow around the higher elevation of the islands, leading to the formation of wakes with reduced modified refractivity. These island wakes may extend dozens of kilometers downstream with the SD height and strength growing accordingly.

The variability of volatile organic compounds during a persistent fog-haze episode

A persistent fog-haze process associated with high pollution occurred in the northern suburbs of Nanjing from November to December 2013. Based on the comprehensive chemical and microphysical observations during the intense observation period, the composition characteristics, and variation rules of volatile organic compounds (VOCs) in the atmosphere under four weather conditions (slight haze, haze, fog, and dense fog) were compared and analyzed, the influencing factors for VOCs during extremely dense fog were discussed in more detail. The average concentrations of VOCs displayed as alkanes > aromatics > alkenes > alkynes, and their concentrations were ranked as dense fog > fog > haze > slight haze, the main factor contributing to the difference in concentrations of VOCs under different weather conditions is the boundary layer characteristics and photochemical reaction rate. Microphysical parameters such as liquid water content (LWC) were negatively correlated with VOCs concentration in dense fog (LWC>0.008 g m−3). Also, the concentration of VOCs showed an oscillating decrease in extremely dense fog (LWC>0.12 g m−3), and the total VOCs removal rate was close to 30%, which may be attributed to an indirect/direct removal effect, in which the enhanced collision and deposition of fog droplets promote the redistribution of VOCs gas-aqueous/particle partitioning, and remove them from the atmosphere by fog water.

Fair-Weather Atmospheric Charge Measurements with a Small UAS

Abstract Atmospheric electricity measurements made from small unmanned aircraft systems (UAS) are rare but are of increasing interest to the atmospheric science community due to the information that they can provide about aerosol and turbulence characteristics of the atmospheric boundary layer (ABL). Here we present the first analysis of a new dataset of space charge and meteorology measurements made from the small, electric, fixed-wing UAS model MASC-3. Two distinct experiments are discussed: 1) Flights past a 99 m metal tower to test the response of the charge sensor to a fixed distortion of the electric field caused by the geometry of the tower. Excellent agreement is found between the charge sensor response from the MASC-3 and modeled electric field around the tower. 2) Vertical profiles up to an altitude of 2500 m to study the evolution of the ABL with the time of day. These flights demonstrated close agreement between the space charge profiles and temperature, relative humidity, and turbulence parameters, as would be expected on a fair-weather day with summertime convection. Maximum values of space charge measured were of order 70 pC m−3, comparable with other measurements in the literature from balloon platforms. These measurements demonstrate the suitability of small UAS for atmospheric electrical measurements, provided that care is taken over the choice of aircraft platform, sensor placement, minimization of electrical interference, and careful choice of the flight path. Such aircraft are typically more cost-effective than manned aircraft and are being increasingly used for atmospheric science purposes.

Experimental study on airfoil flow separation control via an air-supplement plasma synthetic jet

An air-supplement plasma synthetic jet (PSJ) actuator increases the air supplemental volume in the recovery stage and improves the jet energy by attaching a check valve to the chamber of a conventional actuator. To explore the flow control effect and mechanism of the air-supplement actuator, via particle image velocimetry experiments in a low-speed wind tunnel, the flow field and boundary layer characteristics of a two-dimensional airfoil surface under different actuation states were compared for different attack angles and jet orifices. The experimental results show that, compared with the conventional actuation state, the jet energy of the air-supplement PSJ is higher and the indirect mixing effect of the counter-vortex sequence produced by the jet-mainstream interaction is stronger. Furthermore, the boundary layer mixing effect is better, which can further suppress flow separation and improve the critical flow separation attack angle. Moreover, increasing the jet momentum coefficient can enhance the flow control effect. The findings of this study could provide guidance for the flow control application of air-supplement PSJs.