Turbulent kinetic energy and self-sustaining tones: Experimental study of a rectangular impinging jet using high Speed 3D tomographic Particle Image Velocimetry

Impinging jets are widely used in ventilation systems to improve the mixing and diffusion of airflows. When a rectangular jet hits a slotted plate, an acoustic disturbance can be generated and self-sustained tones produced. Few studies have looked at the Turbulent Kinetic Energy (TKE) produced by the aerodynamic field in such configurations and in the presence of self-sustaining tones. The aim of this work is to investigate the energy transfer between the aerodynamic and acoustic fields generated in a rectangular jet impinging on a slotted plate. The present paper methodology is based on experimental data measurements using 3D tomographic Particle Image Velocimetry (PIV) technique and microphones. It was found that the spectrum of the TKE for Re=5294 (configuration of self-sustained tones) is which is smaller than that of the acoustic signal . A negative peak of correlation is obtained between the acoustic signal and TKE for These results may lead to conclude that the acoustic cycle should be covered by the TKE period and the two signals of both fields are in opposition of phase in order to obtain an optimal configuration for energy transfer.

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Spatio-Temporal Changes in the Turbulent Kinetic Energy of a Rectangular Jet Impinging on a Slotted Plate Analyzed with High Speed 3D Tomographic-Particle Image Velocimetry

International Journal of Heat and Technology ◽

10.18280/ijht.370416 ◽

2019 ◽

Vol 37 (4) ◽

pp. 1071-1079 ◽

Cited By ~ 1

Author(s):

Hassan Assoum ◽

Jana Hamdi ◽

Kamel Abed-Meraïm ◽

Marwan Al Kheir ◽

Tarek Mrach ◽

...

Keyword(s):

Particle Image Velocimetry ◽

Kinetic Energy ◽

Turbulent Kinetic Energy ◽

High Speed ◽

Particle Image ◽

Temporal Changes ◽

Tomographic Particle Image Velocimetry ◽

Rectangular Jet ◽

Image Velocimetry ◽

Spatio Temporal

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Experimental Investigation of Unsteady Flow Field Within a Two Stage Axial Turbomachine Using Particle Image Velocimetry

Volume 5: Turbo Expo 2002, Parts A and B ◽

10.1115/gt2002-30664 ◽

2002 ◽

Cited By ~ 1

Author(s):

Oguz Uzol ◽

Yi-Chih Chow ◽

Joseph Katz ◽

Charles Meneveau

Keyword(s):

Particle Image Velocimetry ◽

Kinetic Energy ◽

Flow Field ◽

Turbulent Kinetic Energy ◽

Particle Image ◽

Energy Levels ◽

Shear Stresses ◽

Image Velocimetry ◽

Entire Flow ◽

The Difference

Detailed measurements of the flow field within the entire 2nd stage of a two stage axial turbomachine are performed using Particle Image Velocimetry. The experiments are performed in a facility that allows unobstructed view on the entire flow field, facilitated using transparent rotor and stator and a fluid that has the same optical index of refraction as the blades. The entire flow field is composed of a “lattice of wakes”, and the resulting wake-wake and wake-blade interactions cause major flow and turbulence non-uniformities. The paper presents data on the phase averaged velocity and turbulent kinetic energy distributions, as well as the average-passage velocity and deterministic stresses. The phase-dependent turbulence parameters are determined from the difference between instantaneous and the phase-averaged data. The distributions of average-passage flow field over the entire stage in both the stator and rotor frames of reference are calculated by averaging the phase-averaged data. The deterministic stresses are calculated from the difference between the phase-averaged and average-passage velocity distributions. Clearly, wake-wake and wake-blade interactions are the dominant contributors to generation of high deterministic stresses and tangential non-uniformities, in the rotor-stator gap, near the blades and in the wakes behind them. The turbulent kinetic energy levels are generally higher than the deterministic kinetic energy levels, whereas the shear stress levels are comparable, both in the rotor and stator frames of references. At certain locations the deterministic shear stresses are substantially higher than the turbulent shear stresses, such as close to the stator blade in the rotor frame of reference. The non-uniformities in the lateral velocity component due to the interaction of the rotor blade with the 1st stage rotor-stator wakes, result in 13% variations in the specific work input of the rotor. Thus, in spite of the relatively large blade row spacings in the present turbomachine, the non-uniformities in flow structure have significant effects on the overall performance of the system.

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Scaled Room Three-Dimensional Velocity Measurements Using Particle Image Velocimetry

Fluids Engineering ◽

10.1115/imece2002-33821 ◽

2002 ◽

Author(s):

Steven P. O’Halloran ◽

B. Terry Beck ◽

Mohammad H. Hosni ◽

Thomas P. Gielda

Keyword(s):

Particle Image Velocimetry ◽

Kinetic Energy ◽

Turbulent Kinetic Energy ◽

Particle Image ◽

Three Dimensional ◽

Stereoscopic Particle Image Velocimetry ◽

Measurement Information ◽

Velocity Measurements ◽

Image Velocimetry ◽

Equipment Configuration

A stereoscopic particle image velocimetry (PIV) system was used to measure flow within a one-tenth-scale room. The dimensions of the scaled room were 732 × 488 × 274 mm (28.8 × 19.2 × 10.8 in.). The measurements were made under isothermal conditions and water was used as the fluid instead of air. Six equally spaced vertical planes along the length of the room were captured and symmetry was utilized so that measurements were only made on one side of the room. A sample size of 50 pairs of PIV images were collected and averaged to determine average velocity. Turbulent kinetic energy was also calculated from the collected data. The equipment configuration, measurement information and the velocity and turbulent kinetic energy results are presented in this paper. The measurements provide detailed three dimensional velocity profiles that could be used to validate numerical simulations.

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Extreme events of turbulent kinetic energy production and dissipation in turbulent channel flow: particle image velocimetry measurements

Journal of Turbulence ◽

10.1080/14685248.2020.1727914 ◽

2020 ◽

Vol 21 (1) ◽

pp. 39-51

Author(s):

Dinar Zaripov ◽

Renfu Li ◽

Ilya Saushin

Keyword(s):

Particle Image Velocimetry ◽

Kinetic Energy ◽

Turbulent Kinetic Energy ◽

Channel Flow ◽

Extreme Events ◽

Energy Production ◽

Particle Image ◽

Turbulent Channel Flow ◽

Image Velocimetry ◽

Flow Particle

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Turbulence Measurements at the Inlet of an Automotive Turbocharger Compressor using Stereoscopic Particle Image Velocimetry

Journal of Turbomachinery ◽

10.1115/1.4051712 ◽

2021 ◽

pp. 1-50

Author(s):

Deb Banerjee ◽

Rick Dehner ◽

Ahmet Selamet

Keyword(s):

Particle Image Velocimetry ◽

Kinetic Energy ◽

Turbulent Kinetic Energy ◽

Mass Flow ◽

Particle Image ◽

Stereoscopic Particle Image Velocimetry ◽

Flow Rates ◽

Image Velocimetry ◽

Compressor Inlet ◽

The Mean

Abstract The present work uses Stereoscopic Particle Image Velocimetry (SPIV) to analyze the compressor inlet flow field, with specific emphasis on its turbulence characteristics during flow reversal in order to gain further insight into the inlet flow structures. SPIV experiments were carried out at the inlet of a centrifugal compressor without any recirculation channel at four different rotational speeds (from 80 to 140 krpm) and over the entire mass flow range (from choke to surge) at each speed. Detailed analyses have been carried out for the mean velocity field, the mean vorticity field, and the turbulent statistics including turbulent kinetic energy, Reynolds stress, and the one-dimensional energy spectra. The turbulent kinetic energy at the compressor inlet was observed to increase rapidly along a speed line with decreasing mass flow rate once flow separation started, and the turbulence became more anisotropic. As the flow rate was reduced (along a speed line), the zone with maximum turbulent kinetic energy moved from the periphery toward the center of the inlet duct and also occurred further upstream from the impeller. The Reynolds stress distributions suggest that the Boussinesq assumption of an isotropic eddy viscosity may not be appropriate after the detection of flow reversal. The Reynolds shear stresses were observed to change signs with their corresponding velocity gradients at the tested mass flow rates at different rotational speeds. At the investigated flow rates, the radial gradients in the axial and tangential velocities were found to be most dominant.

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Experimental Investigation of Unsteady Flow Field Within a Two-Stage Axial Turbomachine Using Particle Image Velocimetry

Journal of Turbomachinery ◽

10.1115/1.1509077 ◽

2002 ◽

Vol 124 (4) ◽

pp. 542-552 ◽

Cited By ~ 37

Author(s):

Oguz Uzol ◽

Yi-Chih Chow ◽

Joseph Katz ◽

Charles Meneveau

Keyword(s):

Particle Image Velocimetry ◽

Kinetic Energy ◽

Flow Field ◽

Turbulent Kinetic Energy ◽

Particle Image ◽

Energy Levels ◽

Shear Stresses ◽

Image Velocimetry ◽

Entire Flow ◽

The Difference

Detailed measurements of the flow field within the entire 2nd stage of a two-stage axial turbomachine are performed using particle image velocimetry. The experiments are performed in a facility that allows unobstructed view on the entire flow field, facilitated using transparent rotor and stator and a fluid that has the same optical index of refraction as the blades. The entire flow field is composed of a “lattice of wakes,” and the resulting wake-wake and wake-blade interactions cause major flow and turbulence nonuniformities. The paper presents data on the phase averaged velocity and turbulent kinetic energy distributions, as well as the average-passage velocity and deterministic stresses. The phase-dependent turbulence parameters are determined from the difference between instantaneous and the phase-averaged data. The distributions of average passage flow field over the entire stage in both the stator and rotor frames of reference are calculated by averaging the phase-averaged data. The deterministic stresses are calculated from the difference between the phase-averaged and average-passage velocity distributions. Clearly, wake-wake and wake-blade interactions are the dominant contributors to generation of high deterministic stresses and tangential nonuniformities, in the rotor-stator gap, near the blades and in the wakes behind them. The turbulent kinetic energy levels are generally higher than the deterministic kinetic energy levels, whereas the shear stress levels are comparable, both in the rotor and stator frames of references. At certain locations the deterministic shear stresses are substantially higher than the turbulent shear stresses, such as close to the stator blade in the rotor frame of reference. The nonuniformities in the lateral velocity component due to the interaction of the rotor blade with the 1st-stage rotor-stator wakes, result in 13 percent variations in the specific work input of the rotor. Thus, in spite of the relatively large blade row spacings in the present turbomachine, the nonuniformities in flow structure have significant effects on the overall performance of the system.

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