نتایج جستجو برای: relative roughness

تعداد نتایج: 409536  

Journal: :آب و خاک 0
بهرامی یاراحمدی بهرامی یاراحمدی شفاعی بجستان شفاعی بجستان

abstract in all river engineering projects, determination of flow resistance is essential. most commonly, the manning roughness coefficient, , is used to describe the flow resistance or relative roughness of main channel or flood plane. over the past decades little or no study has been conducted to investigate the effects of particle shapes on manning roughness coefficient. therefore, it is the...

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 ...

2017
KENNETH D. MANKOFF JASON D. GULLEY SLAWEK M. TULACZYK MATTHEW D. COVINGTON XIAOFENG LIU YUNXIANG CHEN DOUGLAS I. BENN PIOTR S. GŁOWACKI

Hydraulic roughness exerts an important but poorly understood control on water pressure in subglacial conduits. Where relative roughness values are <5%, hydraulic roughness can be related to relative roughness using empirically-derived equations such as the Colebrook–White equation. General relationships between hydraulic roughness and relative roughness do not exist for relative roughness>5%. ...

Journal: :civil engineering infrastructures journal 0
rasoul ghobadian hydraulic structures ali fattahi water resource engineering milad farmanifard young researchers club, kermanshah branch, islamic azad university arash ahmadi water civil engineering

different construction materials with different roughness used to make circular weirs highly affect surface roughness and, in turn, flow hydraulics passing over these structures.  in the present research, numerous experiments under different hydraulic conditions were performed on a physical model to study the effects of roughness on flow hydraulics over a circular weir. the flow hydraulics incl...

Journal: :Journal of Water Resource and Protection 2012

2012
M. Hakak Khadem S. Hossainpour

A numerical simulation of micro Poiseuille flow has performed for rarefied and compressible flow at slip flow regimes. The wall roughness is simulated in two cases with triangular microelements and random micro peaks distributed on wall surfaces to study the effects of roughness shape and distribution on flow field. Two values of Mach and Knudsen numbers have used to investigate the effects of ...

2006
James B. Taylor Andres L. Carrano Satish G. Kandlikar

Surface roughness (texture) has an effect on fluid flow in networks which has been studied for well over a century. The exact effect roughness has on fluid flow has not been completely understood, but a working estimate has been offered by a variety of authors over time. The work of Colebrook, Nikuradse, and Moody has provided practitioners with a method to include at least a first order estima...

2008
Timothy P. Brackbill Satish G. Kandlikar

The effect of roughness ranging from smooth to 24% relative roughness on laminar flow has been examined in previous works by the authors. It was shown that using a constricted parameter, εFP, the laminar results were predicted well in the roughened channels ([1],[2],[3]). For the turbulent regime, Kandlikar et al. [1] proposed a modified Moody diagram by using the same set of constricted parame...

2005
James B. Taylor Andres L. Carrano Satish G. Kandlikar

That surface roughness has an effect on fluid flow in networks has been understood for well over a century. The exact effect roughness has on fluid flow has not been completely understood, but a working estimate has been offered by a variety of authors over time. The work of Colebrook, Nikuradse, and Moody has provided practitioners with a method to include at least a first order estimate of ro...

2015

Solar energy is a good option among renewable energy resources due to its easy availability and abundance. The simplest and most efficient way to utilize solar energy is to convert it into thermal energy and this can be done with the help of solar collectors. The thermal performance of such collectors is poor due to less heat transfer from the collector surface to air. In this work, experimenta...

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