Investigation of a laser Doppler velocimeter system to measure the flow field of a large scale V/STOL aircraft in ground effect

1979 ◽  
Keyword(s):  
Flow Field ◽  
Large Scale ◽  
Ground Effect ◽  
Laser Doppler ◽  
Laser Doppler Velocimeter

Integrated Microcomputer-LDV Instrumentation for Studying Finite Wing Aerodynamics

1993 ◽  
Author(s):  
Abdollah Khodadoust
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Data Acquisition ◽  
Fiber Optic ◽  
Three Dimensional ◽  
Laser Doppler ◽  
Laser Doppler Velocimeter ◽  
Ice Accretion ◽  
Wing Model ◽  
Finite Wing

Abstract The effect of a simulated glaze ice accretion on the flow field of a three-dimensional wing is studied experimentally. A PC-based data acquisition and reduction system was used with a four-beam two-color fiber-optic laser Doppler velocimeter (LDV) to map the flow field along three spanwise cuts on the model. Results of the LDV measurements on the upper surface of the finite wing model without the simulated glaze ice accretion are presented for α = 0 degrees at Reynolds number of 1.5 million. Measurements on the centerline of the clean model compared favorably with theory.

Unsteady Aerodynamics of an Aeroengine Double Swirler Lean Premixing Prevaporizing Burner

2004 ◽  
Vol 128 (1) ◽  
pp. 29-39 ◽  
Author(s):  
Edward Canepa ◽  
Pasquale Di Martino ◽  
Piergiorgio Formosa ◽  
Marina Ubaldi ◽  
Pietro Zunino
Keyword(s):  
Flow Field ◽  
Reynolds Stress ◽  
Large Scale ◽  
Unsteady Aerodynamics ◽  
Scale Model ◽  
Flow Structures ◽  
Laser Doppler Velocimeter ◽  
Formation Mechanisms ◽  
Meridional Plane ◽  
Stress Components

Lean premixing prevaporizing (LPP) burners represent a promising solution for low-emission combustion in aeroengines. Since lean premixed combustion suffers from pressure and heat release fluctuations that can be triggered by unsteady large-scale flow structures, a deep knowledge of flow structures formation mechanisms in complex swirling flows is a necessary step in suppressing combustion instabilities. The present paper describes a detailed investigation of the unsteady aerodynamics of a large-scale model of a double swirler aeroengine LPP burner at isothermal conditions. A three-dimensional (3D) laser Doppler velocimeter and an ensemble-averaging technique have been employed to obtain a detailed time-resolved description of the periodically perturbed flow field at the mixing duct exit and associated Reynolds stress and vorticity distributions. Results show a swirling annular jet with an extended region of reverse flow near to the axis. The flow is dominated by a strong periodic perturbation, which occurs in all the three components of velocity. Radial velocity fluctuations cause important periodic displacement of the jet and the inner separated region in the meridional plane. The flow, as expected, is highly turbulent. The periodic stress components have the same order of magnitude of the Reynolds stress components. As a consequence the flow-mixing process is highly enhanced. Turbulence acts on a large spectrum of fluctuation frequencies, whereas the large-scale motion influences the whole flow field in an ordered way that can be dangerous for stability in reactive conditions.

Flow Field Investigation in a Low-Solidity Inducer by Laser-Doppler Velocimetry

1990 ◽  
Vol 112 (1) ◽  
pp. 91-97 ◽  
Author(s):  
A. Boccazzi ◽  
A. Perdichizzi ◽  
U. Tabacco
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Reverse Flow ◽  
Field Investigation ◽  
Design Flow ◽  
Laser Doppler ◽  
Laser Doppler Velocimeter ◽  
Pressure Probe ◽  
Specific Work ◽  
Flow Angle

The results of an experimental investigation of the flow field within a low-solidity inducer at design and off-design flow rates are presented and discussed; particular attention is devoted to the analysis of the flow field, at the tip in front of the leading edge, for the flow rate close to the back-flow onset. The flow field was measured by means of a laser-Doppler velocimeter at four different axial positions upstream, within, and downstream of the inducer. Axial, tangential, and relative flow angle distributions, in the measuring planes, are presented for three different flow coefficients. At the lower flow rate, the plots show the presence of reverse flow in the region close to the hub downstream of the trailing edge. For the same flow rate, quite low axial velocities are detected at the tip. This is in agreement with pressure probe traverses carried out in a slightly downstream section; these measurements also show radial inward velocities of the same order of magnitude as the axial velocities. Circumferentially averaged losses were evaluated from specific work and total head rise given by pressure probes.

scholarly journals Flow Field Measurement around a Marine Propeller by Laser Doppler Velocimeter

1986 ◽  
Vol 29 (248) ◽  
pp. 453-458
Author(s):  
Koichi KOYAMA ◽  
Akira KAKUGAWA ◽  
Michio OKAMOTO
Keyword(s):  
Flow Field ◽  
Field Measurement ◽  
Laser Doppler ◽  
Laser Doppler Velocimeter ◽  
Marine Propeller ◽  
Flow Field Measurement

Laser Doppler velocimeter measurements of flow field around a bluff body

1998 ◽  
Vol 77-78 ◽  
pp. 457-465
Author(s):  
Robert E. Akins ◽  
Nathan E. Hottle ◽  
Timothy A. Reinhold
Keyword(s):  
Flow Field ◽  
Bluff Body ◽  
Laser Doppler ◽  
Laser Doppler Velocimeter

Computational Investigation of a Race Car Wing With Vortex Generators in Ground Effect

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Yuichi Kuya ◽  
Kenji Takeda ◽  
Xin Zhang
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Flow Separation ◽  
Large Scale ◽  
Vortex Generator ◽  
Ground Effect ◽  
Experimental Results ◽  
Vortex Generators ◽  
Flow Physics ◽  
Large Scale Vortex

Vortex generators can be applied to control separation in flows with adverse pressure gradients, such as wings. In this paper, a study using three-dimensional steady computations for an inverted wing with vortex generators in ground effect is described. The main aim is to provide understanding of the flow physics of the vortex generators, and how they affect the overall aerodynamic performance of the wing to complement previous experimental studies of the same configuration. Rectangular vane type sub-boundary layer and large-scale vortex generators are attached to the suction surface of the wing, including both counter-rotating and co-rotating configurations. In order to provide confidence, Reynolds-averaged Navier–Stokes simulations using the Spalart–Allmaras turbulence model are validated against the experimental results regarding force, pressure, and wake characteristics, with the validation exhibiting close agreement with the experimental results. The streamwise friction shows the downwash induced by the generated vortex acts to suppress flow separation. The flow field survey downstream of the vortex generators features breakdown and dominance of the generated vortex in the flow. The vortex generated by the counter-rotating sub-boundary layer vortex generator grows in size and breaks down as it develops downstream, while the vortex generated by the counter-rotating large-scale vortex generator shows high vorticity even further downstream, indicating the persistence of the vortex in the flow. The flow field behind the co-rotating sub-boundary layer vortex generator is dominated by a lateral flow, having the spanwise flow component rather than a swirling flow, and the vortex quickly dissipating as it develops downstream. The results from this paper complement previous experimental measurements by highlighting the flow physics of how vortex generators can help control flow separation for an inverted wing in ground effect, and how critical vortex generator type and size are for its effectiveness.

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