نتایج جستجو برای: coefficient of discharge

تعداد نتایج: 21174747  

In this study electrical discharge process was used to increase surface wear resistance of pure aluminum. Pulse-on-time and pulse current were considered as input parameters of the electrical discharge process. Experimental results reveal that the electrical discharge process is a successful method for improving the surface wear resistance of aluminum, so that this method has greatly increased ...

مصطفی‌ زاده, بهروز , کهنوجی, محمد ,

The emitter discharge is affected by parameters such as pressure, irrigation water temperature, manufacturer’s coefficient of variation, and emitter clogging. In order to study the effects of irrigation water temperature on emitter discharge and to determine the discharge-pressure variations and manufacturer’s coefficient of variations, an experimental trickle irrigation system was designed and...

ژورنال: علوم آب و خاک 2002
مصطفی‌ زاده, بهروز , کهنوجی, محمد ,

The emitter discharge is affected by parameters such as pressure, irrigation water temperature, manufacturer’s coefficient of variation, and emitter clogging. In order to study the effects of irrigation water temperature on emitter discharge and to determine the discharge-pressure variations and manufacturer’s coefficient of variations, an experimental trickle irrigation system was designed and...

Journal: :journal of hydraulic structures 2014
vadoud naderi davood farsadizadeh ali hossein zadeh dalir hadi arvanaghi

one of the causes of perturbation at vertical intakes is the happening of vortices with an air core. the vortices with an air core occur whenever the submergence of the intake is less than a critical value. anti-vortex devices and specially plates are used to avoid the negative effects of the air-core vortices. if plates are used, then the geometry of them should be studied experimentally. acco...

Recently pianokey weirs become important in hydraulic structures. In this paper effect of the number of cycles on the flow of pianokey sideweir has been investigated experimentally. 45 experiments on single, two, four, six cycles pianokey and sharp crest linear weir on different heads (H/P = 0.3, 0.5, 0.65, 0.85 and 1) has been conducted. The input flow rate to the main channel was applied in s...

Journal: :journal of water sciences research 2010
h hajikandi m hatami

in this paper twelve different empirical resistance coefficients expressed in terms of manning's roughness are used apiece in seventeen known compositing methods. the data obtained from ten different cross-sections of the sefidrood river, iran, are used for the evaluation of the empiricalformulas. the present case-study is selected from a reach with gravel bed topology. then no remarkable bed f...

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: :Applied Water Science 2021

Abstract The circular crested weir (CCW) has been introduced as weirs having a high discharge coefficient (Cd). ratio of flow head to the radius crest ( H / R ) is most important parameter affecting Cd, that $${\text{Cd}} \approx a\left( {H/R} \right)^{b}$$ Cd ? a <mml:m...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی عمران 1391

in this study, scour of mashkid bridge pier located in mashkid river of saravan county has been studied and to measure the scour rate, the numerical model hec-ras 4.0 has been used. upon selection of mashkid river as the case study and whereas the studied zone is important with respect to the climatic conditions and showery monsoon raining and flowing the great and destructive floodwaters, ther...

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