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1

The wake behind the sphere; analysis of vortices during transition from steadiness to unsteadiness

Prządka W., Miedzik J., Gumowski K., Goujon-Durand S., Wesfreid J. E.

Archives of Mechanics

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2008

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Vol. 60, nr 6

467-474

EN

This paper reports about an experimental investigation of the wake behind a solid sphere on a low velocity hydrodynamical channel for the Reynolds number in the range 250-310. The aim of the work is to analyze the size and shape of the vortices' cores and its change as a function of the Reynolds number. Special attention is paid to the transition from stationary flow, characterized by two counter-rotating longitudinal vortices, to instationary flow. The two-coloured visualization of the wake in steady and unsteady regimes is also presented.

2

Investigation of Vortex Sensor with Help of Ultrasonic Doppler Anemometer

Goujon-Durand S.

Molecular and Quantum Acoustics

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1999

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Vol. 20

49-58

3

Some guidelines for ultrasonic flowmeter sensors installation for distorted velocity profiles

Goujon-Durand S.

Molecular and Quantum Acoustics

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1998

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Vol. 19

91-102

EN

In the paper experimental data of distorted velocity distńbutions taken by authors and from literature are presented. Mathematical model of distorted velocity profile and velocity distribution is given and mathematical models of flowmeter primary device for fourextan are drown (point velocity measurement, shift method, time-of-flight one path method multipath method). Three measures of the distortion of the velocity distribution shape presented: first for velocity profile, and two for the whole cross-section. Guidelines primary device of ultrasonic flowmeter installation are given. The distance downstream, single elbow in which the velocity distribution is axisymmetrical and flat is to short for, developed velocity distribution and installing the flowmeter is such place gives system error. The velocity meter should be mounted in the place, where velocity is eąual to average velocity in the whole cross-section, but for disturbed velocity distributions it is very difficult to find such place. Multipath primary devices gives smaller errors, and also using straighteners gives decreasing measurement error.