Pulsating Flows: Experimental Equipment and Its Application

Ünsal, Bülent; Durst, F.

doi:10.1299/jsmeb.49.980

Cited by 12 publications

(4 citation statements)

References 9 publications

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“…Work in this direction is already underway, as some of the parameters described here are being considered in guiding and planning controlled experimental and numerical investigations of pulsatory flow with prescribed pressure or mass flow rates. Examples include those carried out by Ray et al [32], Ünsal and Durst [53], Ünsal et al [54,55], and Durst et al [56].…”

Section: Discussionmentioning

confidence: 99%

Exact Navier-Stokes Solution for the Pulsatory Viscous Channel Flow with Arbitrary Pressure Gradient

Majdalani

2008

Journal of Propulsion and Power

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In this article, an exact solution of the Navier-Stokes equations is presented for the motion of an incompressible viscous fluid in a channel with arbitrary pressure distribution. A generalization is pursued by expressing the pressure signal in terms of Fourier coefficients. The flow is characterized by two principal parameters: the pulsation parameter based on the periodic pressure gradient, and the kinetic Reynolds number based on the pulsation frequency. By way of verification, it is shown that for large kinetic Reynolds numbers, the Poiseuille flow may be recovered. Conversely, the purely oscillatory solution by Rott is regained for large pulsation parameters. For sinusoidal pulsations, the flow rate is determined and compared with the steady flow analog obtained under the same pressure gradient. The amount of flow amplification or attenuation is determined as a function of frequency and pulsation parameters. For large frequencies, the maximum flow rate is evaluated and related to the pulsation parameter. By characterizing the velocity, vorticity, and shear stress distributions, cases of flow reversal are identified. Conditions leading to flow reversal are delineated for small and large kinetic Reynolds numbers in both planar and axisymmetric chambers. For an appreciable pulsation rate, we find that the flow reverses when the pulsation parameter is increased to the point of exceeding the Stokes number. By evaluating the skin friction coefficient and its limiting value, design criteria for minimizing viscous losses are realized. The optimal frequency that maximizes the flow rate during pulsing is also determined. Finally, to elucidate the effect of curvature, comparisons between planar and axisymmetric flow results are undertaken. The family of exact solutions presented here can thus be useful in verifying and validating computational models of complex unsteady motions in both propulsive and nonpropulsive applications. They can also be used to guide the design of fuel injectors and controlled experiments aimed at investigating the transitional behavior of periodic flows.

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Section: Discussionmentioning

confidence: 99%

Exact Navier-Stokes Solution for the Pulsatory Viscous Channel Flow with Arbitrary Pressure Gradient

Majdalani

2008

Journal of Propulsion and Power

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“…Huelsz and Lopez-Alquicira [75,76] used HWA to measure acoustic velocities in air with frequencies of 35, 46 and 130 Hz and velocity of 0.3-0.8 m s −1 . Ünsal and Durst [77] studied pulsating laminar and transitional pipe flows using HWA. Their laminar flow investigations showed that the generated sinusoidal mass flow rates agreed well with those of the analytical solution.…”

Section: Hot-wire Anemometrymentioning

confidence: 99%

A critical review on advanced velocity measurement techniques in pulsating flows

Nabavi

Siddiqui

2010

Meas. Sci. Technol.

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Velocity measurement in pulsating flows is more difficult than that in steady flows. One problem follows from the necessity to synchronize the measuring instrument with the characteristic of the flow which is not required for steady-flow measurements. The second challenge is high frequency response of the measuring device which is required for high frequency pulsating flow measurements. Because of development of more advanced measurement devices, there has recently been a growing interest in pulsating velocity measurement and the number of papers in this field has increased significantly in recent years. In this review, the most frequently-used advanced techniques for velocity measurement in pulsating flows are surveyed. The characteristics of different pulsating flows as well as the advantages and limitations of the developed techniques are discussed.

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“…Then, the second intermediate velocity u is calculated. The central difference scheme was used for the viscous terms in (16). The pressure profile was calculated by the following Poisson equation:…”

Section: Two-dimensional Simulation For Analyzing Liquid Pipementioning

confidence: 99%

“…Hwang and Brereton [13] and Brereton and Mankbadi [14] investigated turbulent pulsating pipe flows. Eguchi et al [15] measured the velocity distribution of pulsatile flows in a vertical rigid and elastic tube using a PIV measurement technique.Ünsal and Durst [16] studied both fully developed steady pipe flows and pulsating flows with the Reynolds number ranging from 180 to 18000 and a pipe diameter of 15 mm. He and Jackson [17] investigated pulsating turbulent flows in a pipe using a two-component laser Doppler anemometer (LDA).…”

Section: Literature Surveymentioning

confidence: 99%

Transport Phenomena of Solid Particles in Pulsatile Pipe Flow

Fujimoto

Kubo

Hama

et al. 2010

Advances in Mechanical Engineering

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The transportation mechanism of single solid particles in pulsating water flow in a vertical pipe was investigated by means of videography and numerical simulations. The trajectories of alumina particles were observed experimentally by stereo videography. The particle diameter was 3 mm or 5 mm, and the pipe diameter was 18 mm or 22 mm. The frequency of flow pulsation was less than or equal to 6.67 Hz. It was found that the critical minimum water flux at which the particle can be transported upward depended on the pulsating pattern. Two types of numerical simulations were conducted, namely, one-dimensional simulations for tracking the vertical motion of the solid particles and two-dimensional simulations of the pulsating pipe flows in an axisymmetric coordinate system. The computer simulations of axisymmetric pipe flows revealed that the time-averaged radial velocity profile of water in the pulsating flows was very different from that in steady pipe flows. The motion of the particles is discussed in detail for a better understanding of the physics of the transport phenomena.

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Pulsating Flows: Experimental Equipment and Its Application

Cited by 12 publications

References 9 publications

Exact Navier-Stokes Solution for the Pulsatory Viscous Channel Flow with Arbitrary Pressure Gradient

Exact Navier-Stokes Solution for the Pulsatory Viscous Channel Flow with Arbitrary Pressure Gradient

A critical review on advanced velocity measurement techniques in pulsating flows

Transport Phenomena of Solid Particles in Pulsatile Pipe Flow

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