Schlieren Visualization of Coflow Fluidic Thrust Vectoring Using Sweeping Jets

This research developed a pressure-based thrust vectoring angle estimation method for fluidic thrust vectoring nozzles. This method can accurately estimate the real-time in-flight thrust vectoring angle using only wall pressure information on the inner surface of the nozzle. We proposed an algorithm to calculate the thrust vectoring angle from the wall pressure inside the nozzle. Non-dominated sorting genetic algorithm II was applied to find the optimal sensor arrays and reduce the wall pressure sensor quantity. Synchronous force and wall pressure measurement experiments were carried out to verify the accuracy and real-time response of the pressure-based thrust vectoring angle estimation method. The results showed that accurate estimation of the thrust vectoring angle can be achieved with a minimum of three pressure sensors. The pressure-based thrust vectoring angle estimation method proposed in this study has a good prospect for engineering applications; it is capable of accurate real-time in-flight monitoring of the thrust vectoring angle. This method is important and indispensable for the closed-loop feedback control and aircraft attitude control of fluidic thrust vectoring control technology.

Section: Direct Average Pressure Methodsmentioning

confidence: 99%

Section: Definition Of the Sensor Arrays On The Verification Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An Optimized Pressure-Based Method for Thrust Vectoring Angle Estimation

Shi,

Gu,

et al. 2023

“…NASA [6] first conducted research on the use of FTV for aviation and developed four control methods such as shock vector control (SVC), co-flow control, counter-flow control, and throat skewing or the double throat nozzle (DTN). The fluidic oscillators [7] can be regarded as another kind of FTV that has not been applied. Figure 1 shows a schematic diagram of the typical FTV methods.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic Characteristics of the Novel Two-Dimensional Enhanced Shock Vector Nozzle

Shu,

Gao,

Huang

et al. 2024

Fluid thrust vectoring (FTV) control has obvious advantages in structural quality and stealth performance because of its fast response and light weight. However, improving FTV vector performance will cause a loss in engine performance due to the need to draw airflow from the engine. In order to alleviate the above problems and further improve the vector performance of FTV, a nozzle combined with throat skewing and shock vector control is proposed, and the secondary flow of the nozzle comes from the throat and is injected into the nozzle divergence section. The numerical results indicate that compared with the original configuration, the vector angle and vector efficiency of the new configuration are more linear with the nozzle pressure ratio (NPR), and the vector angle and vector efficiency are improved by 163% and 218%, respectively, while experiencing a maximum reduction in the thrust coefficient of 1.4%. Compared with the only bypass-type shock vector nozzle, the new configuration utilizes the diversion of the two jets to eliminate the reattachment of the separation bubble after the jet and its resulting abrupt change in vector performance, improving the performance while having good control characteristics. Additionally, a sensitivity analysis of the spacing between two jets is also carried out. The spacing between two jets should be increased to make the flow pass through two weaker shock waves to improve the vector performance while ensuring that the separation after the jet is no longer attached.

“…Computational work on flow dynamics behavior in two-dimension DTN using different input functions, such as step and ramp, were carried out by Ferlauto and Marsilio [19]. Another interesting work in the area of co-flow FTV is Wen et al [20], who modified secondary co-flow from conventional steady flow to a sweeping jet. In this approach, the authors claimed to have better flow mixing, leading to better efficiency.…”

Section: Introductionmentioning

confidence: 99%

Mathematical Modelling and Fluidic Thrust Vectoring Control of a Delta Wing UAV

Tanveer

Ahmad

2023

Pitch control of an unmanned aerial vehicle (UAV) using fluidic thrust vectoring (FTV) is a relatively novel technique requiring no moving control surfaces, such as elevators. In this paper, the authors’ previous work on the characterization of a static co-flow FTV rig is further validated using the free to pitch dynamic test bench. The deflection of a primary jet after injection of a high-velocity secondary jet was captured using the tuft flow visualization technique, along with the experimental recording of subsequent normal force impinged on the Coanda surface resulting in the pitching moment. The effect of primary and secondary flow velocities on exhaust jet deflection, as well as on the pitch angle of the aircraft, is examined. Aerodynamic gain as well as the inertia of a delta wing UAV test bench are computed through experiments and fed into the equation of motion (e.o.m). The e.o.m developed aided in the design of a model-based PID controller for pitch motion control using the multi-parameter root locus technique. The root locus tuned controller serves as a benchmark controller for performance evaluation of the genetic algorithm (GA) and particle swarm optimization (PSO) tuned controllers. Furthermore, the frequency domain metric of gain and phase margins were also employed to reach a robust control design. Experiments conducted in a simulation environment reveal that PSO-PID results in a better response of the UAV in comparison to the baseline pitch controller.