نتایج جستجو برای: bed depth

تعداد نتایج: 208458  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی 1392

flow in natural river bends is a complex and turbulent phenomenon which affects the scour and sedimentations and causes an irregular bed topography on the bed. for the reason, the flow hydralics and the parameters which affect the flow to be studied and understand. in this study the effect of bed and wall roughness using the software fluent discussed in a sharp 90-degree flume bend with 40.3cm ...

Journal: :journal of agricultural science and technology 2010
f. shahbazi a. rajabipour

knowledge of airflow resistance is an important consideration in designing an appro-priate ventilation system and for proper fan selection. an airflow resistance device was designed and fabricated to measure the airflow resistance of potatoes. the device the composed of an air compressor, a rotameter, a cylindrical bin to contain the potatoes and an inclined u-tube manometer. airflow resistance...

Journal: :آب و خاک 0
سینا رازی علی حسین زاده دلیر فرزین سلماسی داود فرسادی زاده

in this paper the effectiveness combination of bed sill and collar in reduction of local scour depth at cylindrical piers under clear water flow condition was investigated (v/vc=0.9). in the first of experiments, the bed sill was located in downstream and different distances from the piers. results indicated that minimum distance of the bed sill from the piers in downstream has maximum reductio...

ژورنال: بوم شناسی آبزیان 2015
Shahbazi Naserabad, Saeid , Zamani Faradonbe, Mazaher , Eagderi, Soheil , Poorbagher, Hadi ,

This study was conducted to investigate the relationship between body shape and environmental factors related to a rivarian ecosystem in Kura barbel (Barbus cyri) of the Sefidrud River basin. For this purpose, a number of 285 specimens were sampled from three rivers with different habitat properties including the Taleghan, Totkabon and Kloraz Rivers. The relationship between body shape (extract...

Journal: :TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B 1981

Journal: :مهندسی عمران فردوسی 0
حسین شریعتی سعیدرضا خداشناس کاظم اسماعیلی

scoure is the removal of particle sediment which results variation of flow pattern. local scour is considered as one of the reasons of instability and ultimately failure of bridges.therefore, proposing some controlling methods to reduce this phenomenon is essential. in the study, effects of two types of squar and circular collar on a single cylindrical model have been investigated. in the next ...

ژورنال: علوم آب و خاک 2011
داود فرسادی زاده , , علی حسین زاده دلیر, , پریا شجاعی, ,

Submerged vanes are low aspect ratio flow-training structures mounted vertically on the river bed at an angle to the prevailing flow. The aim of application of vane is to generate a secondary circulation in the main flow, designed to modify the near-bed flow pattern and thus redistribute flow and sediment transport within the channel cross section. Collar is a flat sheet with low thickness fixe...

Journal: :caspian journal of enviromental sciences 0

knowledge of habitat requirements of aquatic animals plays an important role in fisheries and protection programs of aquatic ecosystems. hence, this study was conducted to investigate the suitability indexes of habitat use and habitat suitability index (hsi) of barbus cyri in its distribution range in tootkabon river. a number of environmental variables, including elevation, water depth, river ...

Journal: :مهندسی عمران فردوسی 0
عبدا... اردشیر روح ا... چراغچی حجت کرمی

local scour around the abutment is of utmost importance in bridge failures. numerous methods such as riprap have been proposed to reduce the destructive effects of scouring; one of the ways to harness and reduce the local scour depth is installed protective collars around the abutment. in this paper effect of collar elevation (upper level, bed level and lower level), collar geometry and its siz...

When depth of flow past a river bridge exceeds opening under the bridge, the flow under the bridge becomes pressurized. The water is directed downward and under the bridge deck, causing increase in velocity and shear stress on the bed thereby increasing bed scour. This is termed as Pressure Flow Scour. The present study investigates the phenomenon of pressure flow scour resulting from a submerg...

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