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Compared to a variety of mechanical vectoring nozzles, fluidic vectoring nozzles possess more research value nowadays. The dual throat nozzle is gradually developing into an outstanding technology to handle supersonic and hypersonic aircraft deflections. Three-dimensional, steady, compressible, and viscous flows in rectangular dual throat nozzles are numerically investigated by resolving Reynolds-averaged Navier-Stokes equations and shear stress transport k-omega turbulence model. Computational fluid dynamics results are verified against the existing experimental data, where a good consistency is gained. The impacts of nozzle pressure ratio, injection-to-mainstream momentum flux ratio, and setup angle of the slot injector on the systemic performance are examined. Useful conclusions are summarized for engineering designers. Firstly, pitching angles decline along with an increasing nozzle pressure ratio, while systemic thrust ratio and thrust efficiency increase. Secondly, thrust vector angles enlarge with an increase of the injection-to-mainstream momentum flux ratio, whereas both systemic thrust ratio and thrust efficiency decay. Finally, the setup angle of the slot injector impacts the systemic performance remarkably. Although the pitching angle for the setup angle of 120° is highest, comprehensive characteristics in terms of systemic thrust efficiency and systemic thrust ratio for the setup angle of 150° are more excellent.

In this paper the performance of an internal strut-based thrust vector control (TVC) system has been studied at different expansion conditions of propulsion nozzle. The TVC system uses a cylindrical strut inserted through the diverging wall of a supersonic nozzle. This TVC system can be construed as an alternative to secondary injection TVC method. The nozzle had an expansion ratio of 1.545 and nozzle pressure ratio (NPR) of 6.61 for optimum expansion. Numerical simulations were performed at over-expansion (NPR = 3.94) and under-expansion (NPR = 7.89) conditions for four strut locations (x s ) and five strut heights (h s ). The strut location from the nozzle throat corresponded to 33%, 50%, 66.7% and 80% of the diverging length (L d ) of the nozzle. The schlieren images of the nozzle exhaust and nozzle internal wall pressure distribution from experiments were compared with the results from numerical simulation and the agreement was quite good. Computational results show that introduction of the strut caused a maximum total pressure loss of 1.5% at its maximum height. The calculations also show that$ \\pm $4^{\\circ}$thrust deflection angle could be achieved using combinations of strut location and strut height over a range of nozzle operational conditions. Thrust vectoring performance of strut insertion TVC was evaluated using a parameter called vectoring performance index (VPI) defined as thrust deflection angle per unit percentage of pressure loss. The maximum VPI was observed when x s =0.5L d at${\\bar{h_s}} = 0.429$in both over-expansion and under-expansion conditions. The study reveals that an internal strut based TVC has a good future potential to be developed as an alternate TVC system obviating the requirement of carrying a fluid tank for a system like secondary injection TVC.

For thrust vectoring, combustion characteristics, infrared radiation reduction, and aeroacoustics noise mitigation, the mixing enhancement and core length reduction of a jet must occur without a substantial loss of thrust. Manipulating flow parameters enables the enhancement of the jet mixing process. Nozzle exits fitted with varying tab designs have the potential to alter the flow characteristics in the subsonic jets. The present study uses a ring tab to investigate the influence of the jet spread. These tab configurations are the source of creating counter-rotating vortices of varied sizes due to their even curvature in the plane of the flow. Non-uniform vortices at the orifice perimeter cause differential jet spread, resulting in axis switching and improved mass entrainment properties. The experimental results of the ring tab are compared with the free jet configuration at subsonic exit Mach numbers 0.4, 0.6 and 0.8. The Ring tab showed a significant decrease in the potential core, with reductions of 40%, 60% and 91.67% at Mach numbers 0.4, 0.6 and 0.8, respectively, indicating a substantial improvement in jet mixing. Additionally, the jet decay was faster than the free jet, demonstrating the potential of the ring tab in altering flow characteristics. The radial profiles and Mach contour plots illustrate the Mach decay, indicating the rate at which the jet spreads and the jet deflection from its centerline. This study presents a new tab configuration by providing a single circular ring tab instead of the typical dual tab layout. The main objective of this experimental study involving ring tab is to enhance jet mixing and perhaps decrease the core length, with potential applications in reducing noise and providing thrust vectoring in aircraft engine jets.

This study investigates coal damage mechanisms under water jet deflection angles of 0°, 30°, 45°, and 60° through theoretical analysis, numerical simulation, laboratory experiments, and field validation. Theoretical analysis revealed that jet angle significantly affects velocity decomposition and water accumulation, influencing damage characteristics. Numerical simulations using LS-DYNA demonstrated that damage depth decreases while damage width increases with increasing jet angle. Coal damage volume peaked at 45°, being 127% greater than vertical jetting. Laboratory experiments confirmed these patterns, with coal output following the trend: 45° (225 g) > 30° (206 g) > 60° (182 g) > 0° (99 g). Field tests at Zhaojiazhai Mine validated that 45° jetting achieved optimal coal removal (3.25t average), 141% higher than vertical jetting (1.35t). These findings provide quantitative guidance for optimizing hydraulic slotting operations, with 45° identified as the optimal angle for maximizing coal damage volume while balancing depth and width considerations. Article highlights The mechanism of coal damage caused by the jet deflection angle was revealed, and the morphological and volumetric characteristics of the damaged coal were analyzed. Through laboratory visualization and quantitative experiments, the influence of the jet deflection angle on the damage morphology and volume of coal was clarified. The reliability of the results was verified through on-site industrial tests, providing a theoretical foundation for practical production.

In the long-distance thermal air heating process of large space buildings, there are common problems of thermal air trajectory deflection and low energy efficiency caused by thermal buoyancy. This study proposes an induced air supply system that is easy to design for integration; that is, adding a high-velocity ambient temperature induced airflow above the thermal jet, which can instantly and efficiently suppress the buoyancy of the thermal jet and maintain its axial center temperature, thereby achieving good heating performance. This study uses a numerical simulation method to analyze the effect of the induced airflow and compares the flow field characteristics and heating performance of a single thermal jet and an induced air supply system. The results show that the greater the velocity of the induced airflow, the wider the control range of the thermal jet; the induced airflow can reduce the mixing of the thermal jet and the ambient airflow, and effectively suppress the deflection of the thermal jet and increase its axial center temperature; when the target area is close to the air inlet (y/D ≤ 7.5), the single thermal jet air supply can be used, because too small a deflection height will cause more induced airflow to enter the target area, which will worsen the heating effect. The induced air supply system is best for improving the average temperature of the target area at y/D = 15; as the target distance increases, on the premise of ensuring the blowing feeling, it is possible to consider increasing the induced airflow velocity to obtain a higher heating gain.

In the realm of aviation, jet propulsion systems serve to provide enhanced maneuverability and to make sure that the aircraft thrust is accurately and precisely regulated during take-off and landing operations. The movement of aerodynamic control surfaces (flaps, slats, elevators, ailerons, spoilers, wing attachments) determines the mobility of practically all aircraft types. Recognized as dependable components in the aviation world for take-off and landing tasks, these control surfaces are being replaced by fluidic thrust vectoring (FTV) systems, especially in small unmanned aerial vehicles (UAVs) and short or vertical take-off and landing aircraft. The FTV system is capable of directing thrust in any preferred direction without the need for any movable components. This paper numerically examines the FTV system by utilizing computational fluid dynamics (CFD) and an optimization technique based on gradients of the system components to understand the physics of the Coanda effect in FTV systems. This research employs gradient-based optimization for nozzle design in order to optimize the parameter space for different velocity ratios (VR) by calculating the moment around the upper Coanda surface, which is used to represent the jet deflection angle. In that context, four different Coanda surface-pintle pair designs for four different VRs are produced. The parameter space shows significant improvement in all four configurations, and results reveal that all output parameters successfully delay separation on the thrust vectoring system's upper Coanda surface. Finally, four optimum design suggestions are tested at various VRs, and the most efficient and proper design is recommended based on output parameters.

The synthetic jet actuator was applied to the nozzle jet vector control by experimental and numerical simulation methods to study fluid thrust vector control in this paper. The nozzle jet produced a steady and continuous deflection under the action of synthetic jet actuators. Through the analysis of the flow structure and control mechanism of the interaction between the synthetic jet and the nozzle jet, it was found that the force formed by the pressure gradient in the nozzle duct, the entrainment and ejection of the synthetic jet to the mainstream, and the momentum synthesis of the vertical synthetic jet were able to cause the deflection of the nozzle jet. The actuator excitation voltage can adjust synthetic jet velocity, which in turn affects the nozzle jet deflection angle.

Pleated cartridge filters are widely used to remove dust in industrial processes. However, pulse-jet cleaning is not uniform on the filter cartridges. The phenomenon of pulsed jet airflow deflection exists during pulse jet cleaning, which causes a large impact on the local area of filter cartridge and shortens the service life of the filter cartridge. But perhaps due to the lack of effective testing methods, the impact of pulsed jet deflection on dust cleaning is often ignored. Under more comprehensive conditions, such as jet pressures, jet distance, and jet-hole diameter, the influence of the pulsed jet airflow deflection on the cleaning performance of the filter cartridge has been discussed systematically, by testing the peak static pressure on the side wall of the filter cartridge. The experimental results show that the sidewall peak static pressure of the face-flow surface of the filter cartridge is greater than that of the back-flow surface due to deflection, and the difference between the two is proportional to the jet-hole diameter and jet pressure. After installing the diversion nozzle, the results show that the peak static pressures of the face-flow and back-flow surfaces are basically the same. Therefore, it is proved that the diversion nozzle can effectively correct the jet airflow deflection.

Yawing wind turbines has emerged as an appealing method for wake deflection. However, the associated flow properties, including the magnitude of the transverse velocity associated with yawed turbines, are not fully understood. In this paper, we view a yawed turbine as a lifting surface with an elliptic distribution of transverse lift. Prandtl’s lifting line theory provides predictions for the transverse velocity and magnitude of the shed counter-rotating vortex pair known to form downstream of the yawed turbine. The streamwise velocity deficit behind the turbine can then be obtained using classical momentum theory. This new model for the near-disk inviscid region of the flow is compared to numerical simulations and found to yield more accurate predictions of the initial transverse velocity and wake skewness angle than existing models. We use these predictions as initial conditions in a wake model of the downstream evolution of the turbulent wake flow and compare predicted wake deflection with measurements from wind tunnel experiments.

In the combustion chamber of the scramjet, liquid fuel enters the supersonic crossflow in the form of liquid jet in crossflow (LJIC), and the jet interacts with the crossflow to complete atomization. As the initial stage of the combustion process, fuel atomization has a significant impact on the scramjet combustion efficiency and stability. Investigating the atomization and vortex characteristics of liquid fuel jet in supersonic crossflow is of great significance for scramjet design. The Coupled Level-Set and Volume of Fluid (CLSVOF), large eddy simulation (LES), and adaptive mesh refinement (AMR) were simultaneously used in this article to simulate ellipse jet in supersonic crossflow. The atomization characteristics of liquid jets with ellipse nozzles with different aspect ratios (AR) in supersonic crossflow at Ma = 2.85 were explored. It is found that ellipse jets with small AR have strong anti-deflection ability, large penetration, large spanwise range, dense surface waves, stiff bow shock waves, small recirculation zone, and sparse vortex distribution. Ellipse jets with large AR have easy deflection, small penetration, small spanwise range, sparse surface waves, curved bow shock waves, large reflux area, and dense vortex density. CaseAR0.25 has the highest penetration, 42.8% greater than caseAR4, as well as the largest spanwise range, 45.1% bigger than caseAR4. Among all cases, caseAR0.25 has the maximum number of surface waves (8), while caseAR4 has the minimum (3). These findings have guiding significance for the enhancement of the atomization of jet in supersonic crossflow.