نتایج جستجو برای: wetted perimeter

تعداد نتایج: 6763  

2006
W. M. Soyars J. L. Schiller

Open channel fluid flow principles are applied to understand how helium might behave in the event of a release or spill in a long tunnel enclosure. An example would be helium flowing along the Tevatron accelerator tunnel as a result of some rupture of a header system. Buoyant forces would drive the helium along the ceiling until a vent to atmosphere is reached. An analogy is water flowing up to...

Journal: :آب و خاک 0
محمد حسین نوری قیداری محسن عبدشریف اصفهانی لیلا ابراهیمی

abstract given the importance of environmental cycles had led to allocation of water-right for water species and ecosystems which is known as environmental flow or in stream flow. from among the various methods for estimating environmental flow, building block approach is considered as a very powerful tool for estimating the water needs. in this paper, beside simplifying the building block appr...

Journal: :تحقیقات مهندسی کشاورزی 0
ابوالفضل ناصری استادیار پژوهش بخش تحقیقات فنی و مهندسی مرکز تحقیقات کشاورزی و منابع طبیعی آذربایجان شرقی محمدرضا نیشابوری استاد گروه خاکشناسی دانشکده کشاورزی دانشگاه تبریز

soil infiltration characteristics affect the design, evaluation and management of furrow irrigation over afield. on the other hand, different variables influence furrow infiltration, making infiltration modeling for afield a complex process. this study was conducted to investigate the direct and indirect effects of allvariables affecting furrow infiltration. the blocked furrow method was used t...

This paper applies an evolutionary algorithm, the particle swarm optimization (PSO), to design the optimum open channel section. Depth, channel side slope and bottom width are considered as the variables for rectangular, triangular and trapezoidal channels, respectively. The objective function is minimizing the construction cost of the channel section. MATLAB software is used for programming an...

H Bonakdari M Moazamnia

Flow-rate measurement in rivers under different conditions is required for river management purposes including water resources planning, pollution prevention, and flood control. This study proposed a new discharge estimation method by using a mean velocity derived from a 2D velocity distribution formula based on Tsallis entropy concept. This procedure is done based on several factors which refl...

In the Manning equation the hydraulic radius can be defined as the cross-section dimension of the shape. In pipe flow the bed shear stress is assumed to be uniformly distributed along the wetted perimeter which cannot be true in open channel flow. Hence, three approximation of the true boundary shear-stress distribution are examined and more practical conveyance depth or resistance radius formu...

Journal: :journal of water sciences research 2013
m moazamnia h bonakdari

flow-rate measurement in rivers under different conditions is required for river management purposes including water resources planning, pollution prevention, and flood control. this study proposed a new discharge estimation method by using a mean velocity derived from a 2d velocity distribution formula based on tsallis entropy concept. this procedure is done based on several factors which refl...

2001
Cliff R. Hupp

Rivers of the Coastal Plain of the southeastern United States are characteristically low-gradient meandering systems that develop broad floodplains subjected to frequent and prolonged flooding. These floodplains support a relatively unique forested wetland (Bottomland Hardwoods), which have received considerable ecological study, but distinctly less hydrogeomorphic study. The hydroperiod, or an...

Journal: :Environmental Modelling and Software 2006
Freeman J. Cook P. Fitch Peter J. Thorburn P. B. Charlesworth K. L. Bristow

Irrigation practices that are profligate in their use of water have come under closer scrutiny by water managers and the public. Trickle irrigation has the propensity to increase water use efficiency but only if the system is designed to meet the soil and plant conditions. Recently we have provided a software tool, WetUp, to calculate the wetting patterns from trickle irrigation emitters. WetUp...

ژورنال: علوم آب و خاک 2015
قیصری, مهدی, لندی, اسماعیل, محمدزاده, فهیمه,

The objectives of this study were to investigate the effect of dripper discharge and irrigation time on the wetted width in the sandy loam soil with high percentage of gravel and to evaluate previously developed models of estimation of the wetted width in the previous researches. The treatments included three irrigation times (T) of 4, 8 and 12 h and three dripper discharge rates (q) of 2, 4 an...

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