نتایج جستجو برای: hydraulic head

تعداد نتایج: 195591  

2006
K. Schwärzel

As compared with mineral soils, there are few in situ measurements of the unsaturated hydraulic properties of peat soils available. We used parameter estimation (inverse) methods to estimate the water retention and hydraulic conductivity functions of drained peat soils from both laboratory and field data. The laboratory data were obtained on small cores using the traditional evaporation method,...

1999
MIRKHALEGH Z. AHMADI Mirkhalegh Z. Ahmadi

A piezometric head method is proposed to estimate the impermeable layer depth used in drain spacing formulae. The method was tested and compared with soil texture changes and the US Bureau of Reclamation (USBR, 1978) criterion of impermeable layer being one with hydraulic conductivity one tenth to one fifth that of the weighted hydraulic conductivity of the upper layers. The proposed method, wh...

A. Abbaspour S. Hashemikia

Truncated sharp crested weirs are used to measure flow rate and control upstream water surface in irrigation canals and laboratory flumes. The main advantages of such weirs are ease of construction and capability of measuring a wide range of flows with sufficient accuracy. Artificial neural networks (ANNs) and genetic programming (GP) have recently been used for estimation of hydraulic data. In...

2016
Chirag Trivedi Michel J. Cervantes Ole G. Dahlhaug Juan Pérez-Díaz

Hydraulic turbines are widely used to meet real-time electricity demands. Computational fluid dynamic (CFD) techniques have played an important role in the design and development of such turbines. The simulation of a complete turbine requires substantial computational resources. A specific approach that is applied to investigate the flow field of one turbine may not work for another turbine. A ...

Journal: :آب و خاک 0
مرتضی صادقی بیژن قهرمان

abstract scaling methods, which are based on similar media theory, are used to simplify the statistic description of soil spatial variations. to simulate the water flow in heterogeneous soils, simultaneous scaling of soil hydraulic functions, including soil water retention and unsaturated hydraulic conductivity functions, is highly desirable. in the similar media theory, the simultaneous scalin...

Journal: :E3S web of conferences 2021

Hydraulic energy is one of the most important sources renewable today. It also a complementary source to other sources, being only that offers an nonpolluting storage capacity (through pump facilities). Another essential quality hydraulic its ability regulate system allow integration in which process generating depends on factors cannot be controlled (sun, wind, etc.). However, hydropower plant...

Infiltration is the process of water penetration from the ground surface into the soil and is an important process in the hydrological cycle by which surface runoff and groundwater recharge can be linked. Over the years, the importance of the infiltration process resulted in the development of several simplified analytical models for predicting infiltration. These infiltration models range from...

Journal: :تحقیقات آب و خاک ایران 0
محبوبه سادات ملائی دانشجوی سابق کارشناسی ارشد علی مهدوی مزده استادیار گروه مهندسی آب دانشگاه بین المللی امام خمینی (ره) علیرضا وطن خواه استادیار گروه مهندسی آبیاری و آبادانی دانشگاه تهران

in this study, hydraulic properties of low pressure drip irrigation systems were studied under laboratory conditions and using of the pipes that exist in iran. therefore, effect of various heads from 0.45 to 1.8m was evaluated for lateral pipe with outside diameter 32mm and length of 16, 30, 60 and also the lateral pipe with length 16 and outside diameter of 16, 20, 25 and 32mm, on hydraulic ch...

2011
Raj Mohan Singh

Most of the hydraulic structures are founded on permeable foundation. There is, however, no procedure to fix the basic barrage parameters, which are depth of sheet piles/cutoffs and the length and thickness of floor, in a cost-effective manner. Changes in hydrological and climatic factors may alter the design seepage head of the hydraulic structures. The variation in seepage head affects the do...

2005
Shaw-Yang Yang

A mathematical model is presented for a constant-head test performed in a partially penetrating well with a finite-thickness skin. The model uses a no-flow boundary condition for the casing and a constant-head boundary condition for the screen to represent the partially penetrating well. The Laplace-domain solutions for the dimensionless flow rate at the wellbore and the hydraulic heads in the ...

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