Estimation de la distribution tridimensionnelle des vitesses dans un écoulement à surface libre

Assessment of the velocity three-dimensionnal distribution in a free surface flow

Ecole Nationale du Génie de l’Eau et de l’Environnement, 1 quai Koch - BP 61039, 67070 Strasbourg Cedex France

Abstract

To know hydraulic flows on the waste water networks is an essential condition with the good realization of the self-monitoring. Nevertheless, to measure the flows requires a good knowledge of the distribution velocities in the measurement section. We propose here a method of determination of the fields in a given section. After having released a methodology of three-dimensional modeling giving an account of the hydraulic characteristics of a flow on free face, a library of velocity fields (type of section, of water height, mean velocity) was realized. Of the latter simple mathematical formulas can be extracted, allowing the calculation of velocity in any point of the section. This step, coupled with the measurement in various points of space (profiles), enables us to obtain a metrological tool for the measurement of flow.