Search results for "Hydraulic structures"
showing 4 items of 4 documents
Laminated carbonate deposits in Roman aqueducts: Origin, processes and implications
2013
Carbonate deposits in Roman aqueducts of Patara and Aspendos (southern Turkey) were studied to analyse the nature of their regular layering. Optical microscopy and electron-backscattered diffraction results show an alternation of dense, coarsely crystalline, translucent laminae composed of bundles and fans of elongate calcite crystals with their c-axes parallel to the long axis, and porous, fine-grained laminae with crystals at near-random orientation. The ?18O and ?13C data show a strong cyclicity and anti-correlation, whereby high and low ?18O values correspond to dense columnar and porous fine-grained laminae, respectively. Geochemical analyses show similar cyclic changes in carbonate co…
Nonuniform sediment transport and flow characteristics downstream of a hydraulic structure
2014
Bed scouring downstream of hydraulic structures under steady flow conditions: Experimental analysis of space and time scales and implications for mat…
2011
Abstract Sediment transport and bed deformation in alluvial rivers are space and time dependent. The knowledge of the space and time scales can be helpful for the definition of predictive procedures of an alluvial reach response to changing boundary conditions. In this work, attention is paid to scouring process occurring downstream of the rigid basement of a hydraulic structure. The analysis is focused on transient bed profiles which are determined, under steady flow conditions, by a decrease of the upstream sediment transport rate. In particular, the paper is aimed at improving understanding of the space and time scales required by the alluvial system to reach the equilibrium conditions. …
Experimental observation of horizontal coherent turbulent structures in a straight flume
2009
The present paper describes results of laboratory experiments carried out to investigate the evolution of horizontal coherent turbulent structures for different roughness conditions of channel walls. The occurrence of turbulent events (inward interaction, ejection, sweep and burst) is identified through the conditioned quadrant analysis. The filtered data set is used to determine the probability density distribution of each turbulent event. Particular attention is focused on sweep and ejection events and peculiar maps showing the distributions of the horizontal Reynolds shear stress, for each examined experimental condition, are also presented and discussed.