Abstract: This paper describes a velocimeter, based on back-scattering of ultrasonic waves by
particles, designed for velocity measurement of suspended sediments within the flow
of sewer systems. The Ultrasound Pulse Doppler Velocimeter (UPDV) needs no
calibration and is therefore a potentially useful tool for measuring velocities in
laboratory experiments or in sewer systems. The potential of the developed system to
determine the velocity in turbulent pipe flow was investigated. Two different
approaches were used to estimate velocity: the well-known temporal method, i.e., the
Pulse-Pair technique and the spectral identification based method, developed by our
research group. Measurements have demonstrated the ability of the apparatus, on the
one hand, to measure unsteady turbulent velocities, and on the other hand, to
investigate experimentally the statistical properties of homogeneous and isotropic
turbulence. A good agreement between experimental results and theory was observed.
The validation of these laboratory measurements permits to extrapolate them to sewer
systems.
Abstract: The study of two-phase flow, such as liquid-solid suspensions, requires the development of adequate experimental tools. They must allow the determination of both velocity distributions for the two species mixed together. It has been demonstrated that the use of ultrasound velocimetry for two-phase flow is able to characterise the dynamic properties of the transported particles. Then, the sliding velocities can be investigated. A significant change of the velocity profile, due to the presence of the solid phase can be observed. However, the direct interpretation of the measurements appears very difficult. The study of the velocity histograms allows us to determine both fluid and solid particles velocities. We interpret the first of the two peaks as the fluid particle velocity and the second peak as the suspension velocity.
Abstract: This work takes a part of a study of suspended particles transport in sewage networks. Pulsed Doppler ultrasound velocimetry
has been implemented as a mean of investigation. The objective is to determine the turbulent velocity profile and to study the
ability of this instrument to measure turbulence. A good agreement between experimental results and theory was observed. The
validation of these measures in the laboratory makes it possible to extrapolate them in sewage network.
Abstract: This paper describes Katz-Thompson method of assessment of the intrinsic
permeability to liquid water of cement based materials with unique results of mercury
porosimetry. This technique is applied to illustrate the effect of carbonation of
concretes on their transport properties.