<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">The hydraulc characteristics of flow over rectangular broad-crested weirs with varying upstream slopes were experimentally studied. A series of laboratory experiments was performed to investigate the effects of changing upstream slopes from 90° to 75°, 60°, 45°, 30°, 22.5°, 15°, and 10° on the flow surface pattern, discharge coefficient values, approach velocity profile and flow separation zone. In addition, a new mathematical relationship for water surface profile and a new correction factor to estimate discharge coefficient over weirs with various upstream slopes were introduced. The results showed decreasing upstream slopes from 90° to 10° leading to increasing discharge coefficient values and dissipation of the separation zone.</abstract>

School of Civil and Environmental Engineering, Georgia Institute of Technology, USA

Department of Irrigation & Reclamation, Faculty of soil & Water Eng., University of Tehran, Iran

Ministry of Energy, Fars Regional Water Authority, Shiraz, Iran

Flow Characteristics of Rectangular Broad-Crested Weirs with Sloped Upstream Face

<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">This study focuses on modeling hydrological responses of shallow hillslope soil in a headwater catchment. The research is conducted using data from the experimental site Uhlířská in Jizera Mountains, Czech Republic. To compare different approaches of runoff generation modeling, three models were used: (1) one-dimensional variably saturated flow model S1D, based on the dual-continuum formulation of Richards' equation; (2) zero-dimensional nonlinear morphological element model GEOTRANSF; and (3) semi-distributed model utilizing the topographic index similarity assumption - TOPMODEL. Hillslope runoff hydrographs and soil water storage variations predicted by the simplified catchment scale models (GEOTRANSF and TOPMODEL) were compared with the respective responses generated by the more physically based local scale model S1D. Both models, GEOTRANSF and TOPMODEL, were found to predict general trends of hydrographs quite satisfactorily; however their ability to correctly predict soil water storages and inter-compartment fluxes was limited.</abstract>

Hillslope Runoff Generation - Comparing Different Modeling Approaches

<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">Semi-arid regions are characterized by important infrequent rainfall. They often occur in early autumn and give rise to devastating floods. Flooding problems at Wadi Mekerra, located in the Sidi Bel Abbes town (Northwest Algeria), was traditionally the main concern of researchers and government officials. In this work, the magnitude of raging flood wave in the studied catchment and the principal causes are discussed. After this, we present the main hydromorphometric features and the results of numerical simulations of flood wave. This simulation is done by using finite volume shock capturing schemes. It concerns applying the first order Godunov scheme and the second order Monotonic Central scheme. The Manning roughness coefficient was used as a calibration parameter. The comparison of numerical results with observed data confirms more stability and accuracy of applied numerical schemes in rising limb phase than in the falling limb phase. These results provide information on flood forecasting and monitoring of changes in the magnitude of the flow in Wadi Mekerra.</abstract>

Laboratory of Modeling and Computational Methods, University of Saida, BP 138 Ennasr Saïda 20002, Algeria

Faculty of Engineering, Department of Civil Engineering, University of Djillali Liabes, Sidi Bel Abbes, BP 89, Sidi Bel Abbes 22000, Algeria

Hydrodynamic Investigation and Numerical Simulation of Intermittent and Ephemeral Flows in Semi-Arid Regions: Wadi Mekerra, Algeria

<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">The use of environmentally-friendly materials in hydraulic engineering (e.g. the stone lining of weirs at levees) calls for the more accurate estimation of the discharge coefficient for broad-crested weirs with a rough crest surface. However, in the available literature sources the discharge coefficient of broad-crested weirs is usually expressed for a smooth crest. The authors of this paper have summarized the theoretical knowledge related to the effect of weir crest surface roughness on the discharge coefficient. The method of determination of the head-discharge relation for broad-crested weirs with a rough crest surface is proposed based on known discharge coefficient values for smooth surfaces and on the roughness parameters of the weir. For selected scenarios the theoretical results were compared with experimental research carried out at the Laboratory of Water Management Research, Faculty of Civil Engineering (FCE), Brno University of Technology (BUT).</abstract>

The Influence of Roughness on the Discharge Coefficient of a Broad-Crested Weir

<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">The flow behaviour of coarse-grained slurry depends on particle size, shape, density and concentration, and on the density and rheological properties of the carrier liquid. The present paper describes the results of an experimental investigation and flow visualisation of model coarse-grained particle-water mixtures in a closed pipe loop with smooth stainless steel pipes of inner diameter 36 mm. Glass balls and washed graded pebble gravel of mean diameter <italic>d50</italic>= 6 mm were used as model coarse-grained material. The effect of slurry velocity and particle concentration on the slurry flow behaviour and pressure drop in the turbulent regime was evaluated. Particle distribution in the pipe cross-section and motion of particles along the pipe invert, particle saltation and particle conveying in the carrier liquid were investigated in a transparent pipe viewing section and motion of individual particles was described. Velocity profiles of the carrier liquid and conveyed particles were determined.</abstract>

Flow Structure of Coarse-Grained Slurry in A Horizontal Pipe

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Journal of Hydrology and Hydromechanics

 JOURNAL OF HYDROLOGY AND HYDROMECHANICS is an international open access journal for the basic disciplines of water sciences. The scope of hydrology is limited to catchment hydrology, vadose zone hydrology and biohydrology, primarily of temperate zone. The hydromechanics covers theoretical, experimental and computational hydraulics and fluid mechanics in various fields, two- and multiphase flows, including non-Newtonian flow, and new frontiers in hydraulics. The journal is published quarterly in English. The types of contribution include: research and review articles, short communications and technical notes. The articles have been thoroughly peer reviewed by international specialists and promoted to researchers working in the same field. Authors do not pay any fees.  Why subscribe and read   Source of high quality research from Czech Republic and Slovakia, as well as from other parts of the world,  Designed to facilitate the exchange of ideas between researchers from different countries,  Excellent articles authored by researchers from all over the world.   Why submit   Relatively fast, fair and constructive peer-review provided by 2 international specialists (The average review process duration: 151 days in 2015, 169 days in 2016, 177 days in 2017, 140 days in 2018, and 173 days in 2019),  Extensive promotion of each published article to the researchers working in the same field.   Archiving  Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.  Plagiarism Policy  The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. 