Characteristics of the ground vortex developed by various V/STOL jets at forward speeds

2000

Journal of Aircraft

Exhaust gas ingestion can cause many major problems for a short takeoff and vertical landing (STOVL) aircraft operating in ground effect, for example, engine surge. As part of a program of experimental and computational work on intake ingestion problems, a generic twin jet discharge/intake model was designed, constructed, and tested in a water tunnel especially designed for STOVL ow applications. Tunnel operating conditions were chosen to focus speci cally on the intake ingestion process. Particle image velocimetry (PIV) has now been developed into a well-established technique that can provide two-dimensional spatially resolved velocity measurements in complex uid ows. This technique is used to measure the instantaneous velocity eld in a vertical plane close to the intake. The ow processes important to ingestion (fountain ow, ground vortex, intake suction) are all captured. The large-scale unsteadiness of the ingestion events are studied and quanti ed. For the present jet-discharge/intake con guration, PIV is demonstrated as capable of producing quantitative information on instantaneous eddy structure and its temporal development, which is essential to improving our understanding of the exhaust gas ingestion phenomenon.

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Section: Introductionmentioning

confidence: 99%

Particle Image Velocimetry for Intake Ingestion in Short Takeoff and Landing Aircraft

2000

Journal of Aircraft

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“…see references [1] to [8]). Ground-effect studies are summarized by Stewart and Kuhn [6], who give additional insight into the mechanism of exhaust gas ingestion, particularly at low forward speeds. Although the basic flow mechanisms that dominate ground effect flows around STOVL aircraft are known, details of these mechanisms are not adequately understood.…”

Section: Introductionmentioning

confidence: 99%

Computational fluid dynamics prediction of intake ingestion relevant to short take-off and vertical landing aircraft

Proceedings of the Institution of Mechanical Engineers, Part G:

1999

This item was submitted to Loughborough's Institutional Repository (https://dspace.lboro.ac.uk/) by the author and is made available under the following Creative Commons Licence conditions.For the full text of this licence, please go to: http://creativecommons.org/licenses/by-nc-nd/2.5/ Computational fluid dynamics prediction of intake ingestion relevant to short take-off and vertical landing aircraft P Behrouzi Ã and J J McGuirk Department of Aeronautical and Automotive Engineering, Loughborough University, Loughborough, Leicestershire, UK Abstract: Intake ingestion can cause several major problems (e.g. compressor surge and stall) for short take-off and vertical landing (STOVL) aircraft operating in ground effect. Numerical predictions of the flowfield associated with a generic twin-jet plus intake model operating under ingestion flow conditions are reported using computational fluid dynamics (CFD) techniques. The results have been compared with laser Doppler anemometry (LDA) validation measurements taken in a specially designed test case configuration. The k±å turbulence model and both first-order and second-order (QUICK) convection discretization schemes were employed. Fine meshes and second-order accurate discretization were found essential to produce solutions close to grid independence. A reasonable prediction of the general flow pattern has been achieved. Several features of the mean velocity field were close to the experimental results; however, the k±å model was shown to produce significant errors in the prediction of the forward penetration distance of the ground sheet flow and in the shape of velocity profiles and turbulence levels near to the intake.

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Untitled

Flow, Turbulence and Combustion

2000