1405 Study on Vortical Structures and Aerodynamic Sound of Longitudinal Vortex System Generated around the Leading Edge of Delta Wings

SummarySolutions to the problem of separated flow past slender delta wings for moderate values of a suitably defined incidence parameter have been calculated by Smith, using a vortex sheet model. By increasing the accuracy of the finite-difference technique, and by replacing Smith’s original nested iteration procedure, to solve the non-linear simultaneous equations that arise, by a Newton’s method, it is possible to extend the range of the incidence parameter over which solutions can be obtained. Furthermore for sufficiently small values of the incidence parameter, new and unexpected results in the form of vortex systems that originate inboard from the leading edge have been discovered. These new solutions are the only solutions, to the author’s knowledge, of a vortex sheet leaving a smooth surface.Interest has centred upon the shape of the finite vortex sheet, the position of the isolated vortex, and the lift, and variations of these quantities are shown as functions of the incidence parameter. Although no experimental evidence is available, comparisons are made with the simpler Brown and Michael model in which all the vorticity is assumed to be concentrated onto an isolated line vortex. Agreement between these two models becomes very close as the value of the incidence parameter is reduced.

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On the Breakdown at High Incidences of the Leading Edge Vortices on Delta Wings

Journal of the Royal Aeronautical Society ◽

10.1017/s0368393100073314 ◽

1960 ◽

Vol 64 (596) ◽

pp. 491-493 ◽

Cited By ~ 19

Author(s):

B. J. Elle

Keyword(s):

High Speed ◽

Endwall Heat Transfer Measurements in a Staggered Pin Fin Array With an Adiabatic Pin

Volume 4: Turbo Expo 2007, Parts A and B ◽

10.1115/gt2007-27432 ◽

2007 ◽

Cited By ~ 21

Author(s):

Forrest E. Ames ◽

Chad A. Nordquist ◽

Lindsay A. Klennert

Keyword(s):

Heat Transfer ◽

Turbulent Transport ◽

Infrared Camera ◽

Leading Edge ◽

Reynolds Numbers ◽

Skin Friction Coefficient ◽

Vortex System ◽

Flow Acceleration ◽

Pin Fin ◽

Pin Fin Array

Full surface endwall heat transfer distributions have been acquired in a staggered pin fin array with the use of an infrared camera. Values are presented at Reynolds numbers of 3000, 10,000 and 30,000 based on pin diameter and average velocity through adjacent pins. Average endwall Nusselt numbers agree closely with archival values at each Reynolds number. Locally averaged heat transfer levels show a substantial increase from the inlet through the first few rows and finally a nearly streamwise periodic condition in the second half of the eight row geometry. Increasing levels of heat transfer in the inlet region can be attributed to the leading edge vortex system, flow acceleration around pins, and the generation of turbulence. Distributions of turbulence intensity and turbulent scale are shown to help document the turbulent transport conditions through the array. Detailed endwall Nusselt number distributions are presented and compared at the three Reynolds numbers for the first four and last four rows. These detailed heat transfer distributions highlight the influence of the horseshoe vortex system in the entrance region and the wake generated turbulence throughout the pin fin array. Local velocity and turbulence distributions are presented together with local Stanton number and skin friction coefficient data to examine the aggressive nature of the turbulent mixing.

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Vortex street impinging upon an elliptical leading edge

Journal of Fluid Mechanics ◽

10.1017/s0022112090001550 ◽

1990 ◽

Vol 211 ◽

pp. 211-242 ◽

Cited By ~ 35

Author(s):

Ismet Gursul ◽

Donald Rockwell

Keyword(s):

Velocity Field ◽

Flow Visualization ◽

Pressure Field ◽

Leading Edge ◽

Vortex Street ◽

Transverse Displacement ◽

Vorticity Field ◽

Measured Velocity ◽

Vortical Structures ◽

Pressure Fields

The interaction of a Kármán vortex street with an elliptical edge is investigated experimentally. Basic types of interaction, as a function of scale and transverse displacement of the incident vortex street, are revealed using flow visualization. Unsteady pressure fields induced by these interactions are measured by a phase-averaging technique and correlated with the visualized flow patterns for basic classes of interactions.For a generic vortex–edge interaction, measurements of the phase-averaged velocity field allow construction of streamlines and vorticity contours showing the details of the interaction, including distortion of the vortical structures near the edge. The pressure field is calculated from the measured velocity field and interpreted in relation to the vortical structures.Simulation of flow visualization using the measured velocity field demonstrates possible misinterpretations related to the underlying vorticity field.

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An investigation of asymmetric vortical flows over delta wings with tangential leading-edge blowing at high angles of attack

10.2514/6.1990-103 ◽

1990 ◽

Cited By ~ 4

Author(s):

ZEKI CELIK ◽

LEONARD ROBERTS ◽

N. WOOD

Keyword(s):

Leading Edge ◽

Delta Wings ◽

Vortical Flows ◽

High Angles Of Attack

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