Fluidic throat skewing for thrust vectoring in fixed-geometry nozzles

Miller, Daniel N.; Yagle, Patrick J.; Hamstra, Jeffrey W.

doi:10.2514/6.1999-365

Cited by 63 publications

(25 citation statements)

References 8 publications

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“…In addition, fixed aperture nozzles would enhance lowdetectable integration aspects by eliminating moving flaps, discontinuities, and gaps [2]. For decades the fluidic thrust vectoring nozzles have evolved four main types, shock vectoring control (SVC) [3], counter flow [4], throat shift (TS) [5,6], and dual throat nozzle (DTN) [7]. Each method uses the secondary air source in a certain way.…”

Section: Introductionmentioning

confidence: 99%

Effects of Cavity on the Performance of Dual Throat Nozzle During the Thrust-Vectoring Starting Transient Process

Gu¹,

2013

Journal of Engineering for Gas Turbines and Power

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The dual throat nozzle (DTN) technique is capable to achieve higher thrust-vectoring efficiencies than other fluidic techniques, without compromising thrust efficiency significantly during vectoring operation. The excellent performance of the DTN is mainly due to the concaved cavity. In this paper, two DTNs of different scales have been investigated by unsteady numerical simulations to compare the parameter variations and study the effects of cavity during the vector starting process. The results remind us that during the vector starting process, dynamic loads may be generated, which is a potentially challenging problem for the aircraft trim and control.

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Section: Introductionmentioning

confidence: 99%

Effects of Cavity on the Performance of Dual Throat Nozzle During the Thrust-Vectoring Starting Transient Process

Gu¹,

2013

Journal of Engineering for Gas Turbines and Power

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“…Working best at off-design, over-expanded flow conditions, large thrust vector angles are generated with SVC techniques at the expense of system thrust ratio as the flow is robustly turned, and flow losses occur, through shocks in the nozzle. Throat shifting (TS) methods [8][9][10][11] more efficiently manipulate the subsonic flow upstream of the throat. This technique shifts and skews the nozzle throat plane by fluidic injection at the nozzle throat and typically achieve higher system thrust ratios than shockvector control methods, but usually generate smaller thrust vector angles.…”

Section: Introductionmentioning

confidence: 99%

“…There are three primary mechanisms of fluidic thrust vectoring: shock-vector control, throat shifting, and counterflow [1][2][3][4][5][6][7][8][9][10][11][12][13] . These techniques can be used to vector the exhaust flow in the pitch and yaw directions.…”

Section: Introductionmentioning

confidence: 99%

Computational Study of an Axisymmetric Dual Throat Fluidic Thrust Vectoring Nozzle for a Supersonic Aircraft Application

Deere¹,

Flamm²,

Berrier³

et al. 2007

43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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A computational investigation of an axisymmetric Dual Throat Nozzle concept has been conducted. This fluidic thrust-vectoring nozzle was designed with a recessed cavity to enhance the throat shifting technique for improved thrust vectoring. The structured-grid, unsteady ReynoldsAveraged Navier-Stokes flow solver PAB3D was used to guide the nozzle design and analyze performance. Nozzle design variables included extent of circumferential injection, cavity divergence angle, cavity length, and cavity convergence angle. Internal nozzle performance (wind-off conditions) and thrust vector angles were computed for several configurations over a range of nozzle pressure ratios from 1.89 to 10, with the fluidic injection flow rate equal to zero and up to 4 percent of the primary flow rate. The effect of a variable expansion ratio on nozzle performance over a range of freestream Mach numbers up to 2 was investigated. Results indicated that a 60° circumferential injection was a good compromise between large thrust vector angles and efficient internal nozzle performance. A cavity divergence angle greater than 10° was detrimental to thrust vector angle. Shortening the cavity length improved internal nozzle performance with a small penalty to thrust vector angle. Contrary to expectations, a variable expansion ratio did not improve thrust efficiency at the flight conditions investigated. Nomenclature

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“…Both techniques use the phenomenon of Coanda jet attachment to convexly curved surfaces to enable either efficient control of a primary jet using a secondary jet (FTV) or to eject a tangential jet over a rounded trailing edge for boundary layer control (CC) [6] (see Figs 1 and 2). Some of the approaches to FTV include the shock thrust vector control method [7] and fluidic throat skewing [8] for supersonic jets, the counterflow technique for both subsonic and supersonic jets [9] and co-flow technique for subsonic jets [10]: the reader is referred to reference [11] for a more detailed account of FTV techniques. The co-flow technique in particular is actively explored for use in subsonic aircraft because of its ease of implementation and effectiveness.…”

Section: Introductionmentioning

confidence: 99%

Modelling and robust control of fluidic thrust vectoring and circulation control for unmanned air vehicles

Natesan

Postlethwaite

2008

Proceedings of the Institution of Mechanical Engineers, Part I:

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This paper presents actuator models for fluidic thrust vectoring and circulation control and they are used in the design of a robust controller for an unmanned air vehicle. The pitching and rolling moments for the aircraft are produced through the use of a co-flow fluidic thrust vectoring arrangement at the wing trailing edges. Experimental results for the co-flow actuators are used to derive mathematical models and their performance is compared with conventional control surfaces. For the controller design, nonlinear dynamic models are approximated by a simplified linear parameter varying (LPV) model. The polytopic nature of the controller is exploited to reformulate the LPV controller design problem into a m-synthesis problem. The LPV controllers exhibit superior stability properties over the entire operating region, when compared to conventional gain-scheduling schemes.

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Fluidic throat skewing for thrust vectoring in fixed-geometry nozzles

Cited by 63 publications

References 8 publications

Effects of Cavity on the Performance of Dual Throat Nozzle During the Thrust-Vectoring Starting Transient Process

Effects of Cavity on the Performance of Dual Throat Nozzle During the Thrust-Vectoring Starting Transient Process

Computational Study of an Axisymmetric Dual Throat Fluidic Thrust Vectoring Nozzle for a Supersonic Aircraft Application

Modelling and robust control of fluidic thrust vectoring and circulation control for unmanned air vehicles

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