Stéphane Fischer

• PhD. Eng. @UBERTONE
• R&D Manager at Ubertone

In order to improve sand transport models, the coastal engineering community needs data collected in natural conditions. In particular, sand transport processes in the wave boundary layer still need to be investigated, but the high temporal and spatial variability observed in this area makes it complicated to monitor it properly. In order to addres...

In order to improve sand transport models, the coastal engineering community needs data collected in natural conditions. In particular, sand transport processes in the wave boundary layer still need to be investigated, but the high temporal and spatial variability observed in this area make it complicated to monitor it properly. In order to address...

Suspended Particulate Matter (SPM) measurements are a very important challenge of operational flow monitoring. The ANR project MESURE led to the development of a compact dual-frequency ABS prototype tested on a river. Following this research project, a compact commercial version was developed by Ubertone, composed of a hyperband acoustic module, an...

Measuring velocity profiles in turbulent flows has always been of great theoretical and practical interest. It allows the statistical characterisation of turbulence and better understanding of processes such as sediment motion, closely related to the flow turbulence. A full agreement on how turbulent flows are affected by presence of particles is y...

As Ubertone’s first goal is to bring the UVP technology to more users and applications, we follow several RTD axes. One axis concerns the multiplication of measured velocity components along a profile, while keeping a high space-time resolution, which led to the UB-Lab 2C, launched in 2018, a commercial ADVP (Acoustic Doppler Velocity Profilers). A...

Through its hardware size, the installation and handling of UVPs was not convenient. Also the setup complexity limited the UVP technology to trained users or ultrasonic technology experts. In this extended abstract, we present the world's first handheld UVP, which simplifies its use on large setups and moving systems. The UB-Lab P has, through the...

This is the result of the post-processing of raw acoustic backscattered signal measured with the UB-SediFlow, an ABS by UBERTONE. It allows to get full concentration profiles over the whole river depth and to monitor concentration distribution evolution in time and space.

We present the hydroacoustic inversion tool HYDRAC. This versatile open-source software, developed in Python 3, offers the capability to read hydroacoustic data from widelyused instruments (eg. ABS, ADCP,…) and perform acoustic inversions following several advanced methods found in the literature to estimate the Suspended Particulate Matter mass co...

In the present paper, a data set of time-resolved two components velocity profile measurements under steady uniform turbulent rough clear water and sheet-flow are presented. The purpose of this campaign was to evaluate the performances of a commercial ADVP, the UB-Lab 2C from the company Ubertone, by comparing it to a well-established instrument, t...

In the present paper, new data set of co-located 2C velocity and sediment concentration time-resolved measurements under steady uniform turbulent rough clear water and sheet-flow, performed with an Acoustic Concentration and Velocity Profiler (ACVP) and a prototype for a commercial ADVP, the UB-MES, are presented. The flow regime for the measuremen...

Knowledge on Suspended Sediment Concentration (SSC) leads to a better understanding of sediment transport dynamics, which is of main interest to understand river geomorphology or handle the wastewater regulation and treatment. For this purpose, optical and acoustic turbidity are both used to monitor continuously the suspended solids content in wate...

We studied a measurement using UVP (Ultrasonic Velocity Profiler) for the milk products flowing in pipe line; here, whole milk, low-fat milk and water-coffee cream were employed as samples of the milk products. Those milk products all include fat as emulsion. Although the diameter of fat particles is much smaller than suitable size of UVP tracer pa...

The suspended sediment concentration (SSC) is a key element for water quality monitoring. Optical turbidity is already widely used as SSC indicator and acoustic backscattering devices are still under investigation. Recent observations on a wastewater network showed huge differences between the behaviour of optical and acoustic turbidity according t...

The knowledge of sewer flows characteristics is relevant for transport processes. In combined sewers, the surface runoff produces hydrographs with significant degree of flow dynamics and unsteadiness directly influencing transport characteristics. However, in-situ observations of velocity and turbulence are rare because of inadequate measuring tech...

Particulate matter (PM) conveyed with urban stormwater can have severe ecological impacts on aquatic ecosystems in case of uncontrolled sewer overflows. Despite that occurrence and variability of PM as a lumped parameter have been studied to large extends, the understanding of dynamically changing PM characteristics (e.g. size distribution), is ver...

Une nouvelle électronique de profileur acoustique a été développée par Ubertone pour des applications de basse consommation et à haute résolution. Avec ce développement, les limites technologiques des UVP (Ultrasonic Velocity Profiler) ont été repoussées pour obtenir un circuit plus léger et plus petit. L’électronique consomme moins et se met en ma...

A new hardware has been developed by Ubertone for low power and high resolution applications. This new development pushes further the technological limits of UVP (Ultrasonic Velocity Profiler) to reach a lighter and smaller board. The electronics consume less and power up very quickly. The device communicates through Modbus protocol over RS485. The...

The knowledge of sediment transport characteristics is an important issue in terms of sewer and surface water management. In order to monitor these phenomena in sewage, the Suspended Solids Concentration (SSC) is usually measured either by ad hoc analysis on samples or by optical turbidity which is the most commonly used continuous measurement tech...

In order to monitor these phenomena, the Suspended Solids Concentration is usually measured either by ad hoc analyzes on samples or continuously by optical turbidity. We compared these conventional techniques to explain, in terms of particle presence, the variations of real time acoustic turbidity. The Ultrasonic Doppler Velocity Profiler (UVP) als...

In order to propose a new sewer inspection method, a velocity/turbidity profiler (Ubertone, UB Flow) has been tested in a laboratory. A 50 m glass flume has been adapted with several lateral connections (with a arnge of diameter, angle, intrusions, cracks), supplied by a 1 m3 tank. Placed just below the free surface on a rotating (to scan the wet s...

Sediment transport, either in natural environment or in sewer systems is of main interest to understand river geomorphology or handle the wastewater regulation and treatment. Knowledge on Suspended Sediment Concentration (SSC) and size distribution leads to a better understanding of sediment transport dynamics. In a wide range of rivers and sewer n...

Ubertone has developed a new hardware for industrial and low power applications. This new development pushes further the technological limits of UVP to reach a lighter and smaller board. The electronics consumes less and powers up very quickly. The device communicates through the Modbus protocol over RS485. The comparison with a reference UVP prove...

The knowledge of flow and turbulence characteristics in open-channel flow is relevant for number of transport and transformation processes. Sewer flow hydrodynamics is relevant for assessment of transport of solute constituents and solid phase in both dry and wet weather flows. Surface runoff produces hydrographs in combined sewers with significant...

The digestion of food is a process composed of different phases. A better knowledge of the entire process allows to design tailor made foods. This study is focused on the retropulsive jet generated by the contractions of the stomach and the impact of this flow field to the disintegration of the food. The antral contraction wave is moving at a const...

This paper focuses on the use of the raw acoustical turbidity and velocity data as a flow online monitoring tool. Its aim is to demonstrate that, with adequate instrumental settings, interesting results can directly be seen on the raw data. As illustration, some experimental results on a combined acoustic turbidity and velocity analysis on a river...

This paper focuses on the use of acoustic turbidity as an online monitoring tool. Some experimental results on river and sewer network are shown. The river data analysis demonstrates the great potential of the acoustic measurements in sediment transport studies. The sewer data shows different application as suspended sediments concentration or wate...

Measurement of fluctuating flows in hydraulic machines is an ongoing challenge because of the need to study, quantify, and improve their performances. Indeed, unsteady effects have an impact on the machine working. Moreover, these effects often appear with a high frequency. Therefore, to study them correctly, a high frequency measurement system is...

Measurement of fluctuating flows in hydraulic machines is an ongoing challenge for which classical flow meter technologies (Differential pressure, Magnetic, Turbine and Propeller) are not well adapted. The ultrasonic pulsed Doppler technique allows to measure instantaneous velocity profiles in a very short time. This paper presents the performances...

This paper presents a collaborative study of the Universities of Strasbourg and Hokkaido with the support of Ubertone. Its goal is to analyze and understand the ultrasound wave behavior at the water-air boundary. Measurements with an Ubertone UB-Flow profiler have been done for different water height and discharge configurations on a flume of 16 me...

The study of hydraulic erosion needs detailed measurements of flow and sediment transport. The ultrasonic velocity profiler (UVP) is one of the most efficient tools in hydraulic research and studies. It is useful in assessing the main velocity field through many measurement cells (profile) and the interpretation of backscattered echoes at different...

Apres un rappel sur l'effet Doppler, les principes courants de mesure de vitesse utilisant les ondes ultrasonores seront rapidement presentes. Cet article se focalisera ensuite sur la methode de mesure utilisant les ondes ultrasonores pulsees, qui presente notamment l'avantage de pouvoir mesurer un profil de vitesses. Plusieurs techniques d'estimat...

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 o...

In the frame of a technological research and innovation network in water and environment technologies (RITEAU, Réseau de Recherche et d'Innovation Technologique Eau et Environnement), our research group, in collaboration with industrial partners and other research institutions, has been in charge of the development of a suitable flowmeter: an ultra...

After a short description of the Doppler effect, common principles usedfor velocity measurements by ultra-sound will be explained. Afterwards, thispaper will focus on the pulsed beam method which allows velocity profilecharacterization. Several estimation techniques might be used to extract thevelocity information from the raw data. Distinction is...

In all measurement techniques one seeks accuracy and precision. In ultrasonic Doppler velocimetry, those qualities strongly depend on signal to noise ratio of the Doppler signal and on the performance of the velocity estimator. The most widely used estimation method in ultrasonic coherent Doppler velocimetry is the pulse pair method. Its success is...

L'un des problèmes rencontrés en gestion des eaux usées est la mesure des flux de polluants. Dans le cadre d’un projet RITEAU, l’IMFS développe un fluxmètre en collaboration avec les industriels IRH Environnement et ULTRAFLUX, le laboratoire CRAN et l’ENGEES. L’objectif de l’étude est de développer un dispositif ultrasonore en réseau d’eau pour la...

L'un des problèmes rencontrés en gestion des eaux usées est la mesure des flux de polluants. Dans le cadre d’un projet RITEAU, débuté en juillet 2003, l’IMFS développe un fluxmètre en collaboration avec les industriels IRH Environnement et ULTRAFLUX, le laboratoire CRAN et l’ENGEES. L’objectif de l’étude est de développer un dispositif ultrasonore...

Doppler velocimetry by pulsed ultrasounds makes it possible to obtain the velocity profile of a fluid flow. The mean velocity estimation is carried out, for each measurement volume, from a so called Doppler signal, obtained from the retrodiffused demodulated sampled signal, whose frequency is proportional to the particles velocitiy. It is shown, in...

In the two experiments, the use of a psychophysical procedure of brightness/darkness cancellation shed light on interactions between spatial arrangement and figure-ground contrast in the perceptual filling in of achromatic and colored surfaces. Achromatic and chromatic Kanizsa squares with varying contrast, contrast polarity, and inducer spacing we...

In the two experiments, the use of a psychophysical procedure of brightness/darkness cancellation shed light on interactions between spatial arrangement and figure-ground contrast in the perceptual filling in of achromatic and colored surfaces. Achromatic and chromatic Kanizsa squares with varying contrast, contrast polarity, and inducer spacing we...

We present a computational model for the hierarchical processing of collinear contour line segments. Visual processing of local feature detectors and grouping across collinear space is accounted for by computations which are consistent with neurophysiological data on orientation selective mechanisms in visual cortex V1.

We present a biologically plausible neural network model for long-range contour integration based on current knowledge about neural mechanisms with orientation selectivity in the primate visual cortex. The network simulates diffusive cooperation between cortical neurons in area V1. Recent neurophysiological evidence suggests that the main functiona...

Real-time sewer networks survey becomes a major key in wastewater regulation. Needs for continuous and precise information, especially in wastewater discharge, increase in importance. In the frame of a technological research and innovation network in water and environment technologies (RITEAU), our research group, in collaboration with industrial p...

Résumé : Il s'agit d'une étude de transport de matières en suspension dans les réseaux d'assainissement. L'instrumentation développée est basée sur le principe de la vélocimétrie ultrasonore doppler pulsée. L'objectif est de déterminer les profils turbulents de vitesse et d'étudier l'efficacité de cet instrument pour mesurer la turbulence. Une bonn...

Nous présentons dans cet article un algorithme pour la mesure des profils de vitesse dans un écoulement chargé par l’utilisation d’ondes ultrasonores pulsées. La méthode employée se base sur l’estimation de la différence du temps d’aller-retour de l’onde émise d’une période d’émission à l’autre par intercorrélation des signaux fenêtrés correspondan...