DBPapers
DOI: 10.5593/SGEM2014/B31/S12.036

EXPERIMENTAL INVESTIGATION ON RECTANGULAR CONTRACTED WEIR FOR MEASURING FLOW RATES FROM SUSTAINABLE URBAN SYSTEMS

M. Carbone, G. Garofalo, F. Salamone, P. Piro
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-13-1 / ISSN 1314-2704, June 19-25, 2014, Book 3, Vol. 1, 275-282 pp

ABSTRACT
The management of runoff and the control of it impact on the environment is typically complex, due to the continued evolution of urban reality and the interaction of different factors, not just technical, but also political, social, environmental and economical. In recent decades the concept of sustainable engineering has spread to cope with the problems of energy conservation and pollution. Low Impact Developments (LIDs) such as green roofs and porous pavements have been introduced for managing urban drainage water and reducing stormwater pollution. Such systems are subject to highly variable and unsteady hydrologic loading typical of small watersheds. The accurate and precise estimation of the effluent hydrographs from a LID is essential to evaluate the retention capacity of the system and the corresponding effluent volumes delivered to the drainage network. However, to date conventional flow rate measuring instruments are not able to accurately detect a large range of flow rates and a combination of more devices covering different ranges of flow rates has been often used. A device with a rectangular contracted weir integrated with a transducer level for measuring effluent flow rates from a LID was proposed. Such device, previously calibrated, was tested under a large range of hydraulic loadings. The effect of parameters such as viscosity, surface tension, weir geometry, Reynolds number on the discharging coefficient was investigated for different flow rates by using a variant of the Evolutionary Polynomial Regression (EPR), a MS – Excel function based on Multi-Objective EPR technique (EPR-MOGA), called EPR MOGA XL as a data-mining strategy. The results showed that the discharge relationship for the rectangular contracted weir was well interpreted by traditional formulas used in the literature. The findings also demonstrated Weber number highly influences the discharging coefficient of the rectangular contracted weir. A formula relating the discharge coefficient with Weber number was, therefore, defined for more precisely measuring the effluent flow rates from such device.

Keywords: Data-mining, EPR, Hydraulic measurements, Sustainable urban systems, Urban hydrology