Vortex Shedding and Noise Radiation from a Slat Trailing Edge

AIAA Journal ◽  
2010 ◽  
Vol 48 (2) ◽  
pp. 502-509 ◽  
Author(s):  
Sanehiro Makiya ◽  
Ayumu Inasawa ◽  
Masahito Asai
Keyword(s):  
Vortex Shedding ◽  
Trailing Edge ◽  
Noise Radiation

Effect of Leading-Edge Serrations on Trailing-Edge-Bluntness Vortex-Shedding Noise Radiation

2019 ◽  
Author(s):  
Seyed Mohammad Hasheminejad ◽  
Tze Pei Chong ◽  
Phillip Joseph ◽  
Giovanni Lacagnina
Keyword(s):  
Vortex Shedding ◽  
Leading Edge ◽  
Trailing Edge ◽  
Noise Radiation ◽  
Vortex Shedding Noise

Numerical Simulation of Noise Radiated from a Blunt Trailing Edge

2014 ◽  
Vol 629 ◽  
pp. 3-8
Author(s):  
Siti Nur Aishah Mohd Haris ◽  
Mohamed Sukri Mat Ali ◽  
Sheikh Ahmad Zaki Shaikh Salim ◽  
Sallehuddin Muhamad ◽  
Muhammad Iyas Mahzan
Keyword(s):  
Numerical Simulation ◽  
Vortex Shedding ◽  
Vortex Generator ◽  
Acoustic Analogy ◽  
Trailing Edge ◽  
Noise Radiation ◽  
Blunt Trailing Edge ◽  
Tone Level

The Lighthill acoustic analogy is applied to estimate the noise radiation from flow over a blunt trailing edge. The blunt trailing edge is an effective vortex generator. Periodic vortex shedding near the trailing edge induces fluctuating lift that radiates a strong Aeolian tone. The frequency of the Aeolian tone is similar to that of the vortex shedding. A 50.1 dB of Aeolian tone level is radiated from this blunt trailing edge.

Some modeling issues on trailing-edge vortex shedding

AIAA Journal ◽  
2001 ◽  
Vol 39 ◽  
pp. 787-793
Author(s):  
Wei Ning ◽  
Li He
Keyword(s):  
Vortex Shedding ◽  
Trailing Edge ◽  
Edge Vortex

Influence of Trailing-Edge Geometry on Hydraulic-Turbine-Blade Vibration Resulting From Vortex Excitation

1960 ◽  
Vol 82 (2) ◽  
pp. 103-109 ◽  
Author(s):  
Gunnar Heskestad ◽  
D. R. Olberts
Keyword(s):  
Boundary Layer ◽  
Turbine Blade ◽  
Vortex Shedding ◽  
Hydraulic Turbine ◽  
Trailing Edge ◽  
Blade Vibration ◽  
Edge Geometry ◽  
Blade Thickness ◽  
Vortex Induced Vibrations ◽  
Approach Velocity

A study was made to determine effects of trailing-edge geometry on the vortex-induced vibrations of a model blade designed to simulate the conditions at the trailing edge of a hydraulic-turbine blade. For the type of trailing-edge flow encountered, characterized by a thick boundary layer relative to the blade thickness, the vortex-shedding frequency could not be represented by any modification of the Strouhal formula. The amplitude of the induced vibrations increased with the strength of a vortex in the von Karman vortex street of the wake; one exception was provided by a grooved edge, which is discussed in some detail. For a particular approach velocity, the vortex strength is primarily a function of the ratio of distance between separation points to boundary-layer thickness, the degree of “shielding” between regions of vortex growth, and frequency of vortex shedding.

Vortex Shedding Analysis in the Wake of a Flat Plate at Low Incidence and Low Reynolds Number

2021 ◽  
Author(s):  
Bastav Borah ◽  
Anand Verma ◽  
Vinayak Kulkarni ◽  
Ujjwal K. Saha
Keyword(s):  
Reynolds Number ◽  
Velocity Field ◽  
Flat Plate ◽  
Vortex Shedding ◽  
Low Reynolds Number ◽  
General Tendency ◽  
Flat Plates ◽  
Trailing Edge ◽  
Low Reynolds ◽  
Low Incidence

Abstract Vortex shedding phenomenon leads to a number of different features such as flow induced vibrations, fluid mixing, heat transfer and noise generation. With respect to aerodynamic application, the intensity of vortex shedding and the size of vortices play an essential role in the generation of lift and drag forces on an airfoil. The flat plates are known to have a better lift-to-drag ratio than conventional airfoils at low Reynolds number (Re). A better understanding of the shedding behavior will help aerodynamicists to implement flat plates at low Re specific applications such as fixed-wing micro air vehicle (MAV). In the present study, the shedding of vortices in the wake of a flat plate at low incidence has been studied experimentally in a low-speed subsonic wind tunnel at a Re of 5 × 104. The velocity field in the wake of the plate is measured using a hot wire anemometer. These measurements are taken at specific points in the wake across the flow direction and above the suction side of the flat plate. The velocity field is found to oscillate with one dominant frequency of fluctuation. The Strouhal number (St), calculated from this frequency, is computed for different angles of attack (AoA). The shedding frequency of vortices from the trailing edge of the flat plate has a general tendency to increase with AoA. In this paper, the generation and subsequent shedding of leading edge and trailing edge vortices in the wake of a flat plate are discussed.

Sound diffraction at a trailing edge

1981 ◽  
Vol 108 ◽  
pp. 443-460 ◽  
Author(s):  
S. W. Rienstra
Keyword(s):  
Vortex Shedding ◽  
Pulse Wave ◽  
Layer Structure ◽  
Harmonic Wave ◽  
Sound Field ◽  
Edge Condition ◽  
Trailing Edge ◽  
Kutta Condition ◽  
High Reynolds ◽  
Sound Diffraction

The diffraction of externally generated sound in a uniformly moving flow at the trailing edge of a semi-infinite flat plate is studied. In particular, the coupling of the sound field to the hydrodynamic field by way of vortex shedding from the edge is considered in detail, both in inviscid and in viscous flow.In the inviscid model the (two-dimensional) diffracted fields of a cylindrical pulse wave, a plane harmonic wave and a plane pulse wave are calculated. The viscous proess of vortex shedding is represented by an appropriate trailing-edge condition. Two specific cases are compared, in one of which the full Kutta condition is applied, and in the other no vortex shedding is permitted. The results show good agreement with Heavens’ (1978) observations from his schlieren photographs, and confirm his conclusions. It is further demonstrated, by an explicit expression, that the sound power absorbed by the wake may be positive or negative, depending on Mach number and source position. So the process of vortex shedding does not necessarily imply an attenuation of the sound.In the viscous model a high-Reynolds-number approximation is constructed, based on a triple-deck boundary-layer structure, matching the harmonic plane wave outer solution to a known incompressible inner solution near the edge, to obtain the viscous correction to the Kutta condition.

PIV Analysis on the Effect of Stator Loading on Transonic Blade-Row Interactions

2010 ◽  
Author(s):  
Scott B. Reynolds ◽  
Steven E. Gorrell ◽  
Jordi Estevadeordal
Keyword(s):  
Vortex Shedding ◽  
Bow Shock ◽  
Trailing Edge ◽  
Shock Interactions ◽  
Transonic Compressor ◽  
Close Spacing ◽  
Topological Features ◽  
Blade Row ◽  
Vortex Size ◽  
Increased Strength

Experiments have been performed to investigate interactions between a loaded stator and transonic rotor. The Blade Row Interaction (BRI) rig is used to simulate an embedded transonic fan stage with realistic geometry (thin trailing edge) which produces a wake through diffusion. Details of the unsteady flow field between the stator and rotor were obtained using PIV. Flow-visualization images and PIV data that facilitate analysis of vortex shedding, wake motion, and wake-shock-interaction phenomena are presented. Stator wake and rotor-bow-shock interactions are analyzed for three stator/rotor axial spacings, and two stator loadings. Specific shed vortices and wake topological features are isolated for each configuration. The data analysis focuses on measuring the vortex size, strength, and location as it forms on the stator trailing edge and propagates downstream into the rotor passage. It was observed that vortex shedding is synchronized to the passing of a rotor bow shock. Results show that the circulation of a vortex increased by 19 to 23% from far to close spacing due to the increased strength of the rotor bow shock impacting the stator trailing edge. Reduction in stator loading decreased shed vortex circulation for the same stator/rotor axial spacing by 20 to 25%. Pitchwise radius of vortices also decreased by 13 to 19% from far to close spacing. Such changes in vortex size and strength should be accounted for to predict the effect of unsteady blade-row interactions on transonic compressor performance.

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