نتایج جستجو برای: hydraulic coefficient

تعداد نتایج: 196741  

R. Sedghi S. Bairami Y. Hoseini

ABSTRACT-Determining hydraulic conductivity of soil is difficult, expensive, and time-consuming. In this study, Algorithm Genetic and geostatistical analysis and Neural Networks method are used to estimate soil saturated hydraulic conductivity using the properties of particle size distribution. The data were gathered from 134soil profiles from soil and lander form studies of the Ardabil Agricul...

Journal: :تحقیقات آب و خاک ایران 0
فرزام حسن نژاد شریفی دانش آموخته کارشناسی ارشد امیر صمدی دانشگاه بین المللی امام خمینی-قزوین-دانشکده فنی و مهندسی- گروه مهندسی آب اصغر عزیزیان قطار عضو هیات علمی گروه مهندسی آب

considering the importance of adequate roughness coefficient estimation in river engineering studies, evaluation of image processing technique in estimating manning’s roughness coefficient in the surface layer of riverbeds carried out in this study. the mentioned approach evaluation conducted by implementing of sieving analysis and digital image processing methods simultaneously for a 7.5km rea...

ژورنال: علوم آب و خاک 2014
مظلوم شهرکی, صادق, هنر, تورج,

Cylindrical and semi-cylindrical weirs are used in water distribution systems for flow measurement in open channels and for control of water surface. Review of literature shows that cylindrical and semi-cylindrical weirs are not widely used in practice. Because of their low construction cost and simplicity, an investigation was done to study cylindrical and semi-cylindrical weirs in terms of th...

ژورنال: سنجش و ایمنی پرتو 2014

Precise measurement of void coefficient in two phase flow is one of important parameters in thermal hydraulic parameters such as average density, two phase flow pressure drop and two phase flow pattern. In this study the void coefficient has been correlated experimentally based on attenuation coefficient gamma ray emitted form 137Cs source passing a rectangular channel. The average void fractio...

2014
Mujib Ahmad Ansari

Hydraulic jumps have immense practical utility in hydraulic engineering and allied fields, such as energy dissipater to dissipate the excess energy of flowing water downstream of hydraulic structures (spillways and sluice gates), efficient operation of flow measurement flumes, chlorinating of wastewater, aeration of streams which are polluted by biodegradable wastes and many other cases. The le...

    The combination of horizontal drilling along with hydraulic fracturing has significantly improved the production of hydrocarbon reservoirs and made it possible to extract the relatively impermeable and uneconomical reservoirs. The production rate of oil and gas wells increases proportional to hydraulic fracture aperture or crack opening displacement (COD). This is an important parameter i...

2012
Ting-Yu Lin Satish G. Kandlikar

The effect of structured roughness on the heat transfer of water flowing through minichannels was experimentally investigated in this study. The test channels were formed by two 12.7 mm wide 94.6 mm long stainless steel strips. Eight structured roughness elements were generated using a wire electrical discharge machining (EDM) process as lateral grooves of sinusoidal profile on the channel wall...

2014
Zhi-hao Liu Qin-he Gao

This paper aims to research the position control of the hydraulic cylinder controlled by the highspeed on-off valve to realize the precise position control. A compound algorithm of proportional integral & speed feedforwarddisplacement feedback is put forward based on the research on the relationship between the duty ratio and the past flow for the high speed on-off valve. The speed feedforwardd...

Jalal SheikhKazemi Mehdi AzhdaryMoghaddam Mojtaba Saneie,

A dam spillway is a hydraulic structure that appropriately and safely diverts the outflow to downstream, so that the dam stability and passing of flood flows can be guaranteed. Compared to straight crest spillway, an Ogee spillway with curvature in plan in a fixed-width can pass more flow. Therefore under the low hydraulic heads and the need for a smaller place in plane, they are considered as ...

2008
A. Bilgil H. Altun

An accurate prediction of the friction coefficient is very important in hydraulic engineering since it directly affects the design of water structures, the calculation of velocity distribution, and an accurate determination of energy losses. However, conventional approaches that are profoundly based on empirical methods lack in providing high accuracy for the prediction of the friction coeffici...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید

function paginate(evt) { url=/search_year_filter/ var term=document.getElementById("search_meta_data").dataset.term pg=parseInt(evt.target.text) var data={ "year":filter_year, "term":term, "pgn":pg } filtered_res=post_and_fetch(data,url) window.scrollTo(0,0); } function update_search_meta(search_meta) { meta_place=document.getElementById("search_meta_data") term=search_meta.term active_pgn=search_meta.pgn num_res=search_meta.num_res num_pages=search_meta.num_pages year=search_meta.year meta_place.dataset.term=term meta_place.dataset.page=active_pgn meta_place.dataset.num_res=num_res meta_place.dataset.num_pages=num_pages meta_place.dataset.year=year document.getElementById("num_result_place").innerHTML=num_res if (year !== "unfilter"){ document.getElementById("year_filter_label").style="display:inline;" document.getElementById("year_filter_place").innerHTML=year }else { document.getElementById("year_filter_label").style="display:none;" document.getElementById("year_filter_place").innerHTML="" } } function update_pagination() { search_meta_place=document.getElementById('search_meta_data') num_pages=search_meta_place.dataset.num_pages; active_pgn=parseInt(search_meta_place.dataset.page); document.getElementById("pgn-ul").innerHTML=""; pgn_html=""; for (i = 1; i <= num_pages; i++){ if (i===active_pgn){ actv="active" }else {actv=""} pgn_li="
  • " +i+ "
  • "; pgn_html+=pgn_li; } document.getElementById("pgn-ul").innerHTML=pgn_html var pgn_links = document.querySelectorAll('.mypgn'); pgn_links.forEach(function(pgn_link) { pgn_link.addEventListener('click', paginate) }) } function post_and_fetch(data,url) { showLoading() xhr = new XMLHttpRequest(); xhr.open('POST', url, true); xhr.setRequestHeader('Content-Type', 'application/json; charset=UTF-8'); xhr.onreadystatechange = function() { if (xhr.readyState === 4 && xhr.status === 200) { var resp = xhr.responseText; resp_json=JSON.parse(resp) resp_place = document.getElementById("search_result_div") resp_place.innerHTML = resp_json['results'] search_meta = resp_json['meta'] update_search_meta(search_meta) update_pagination() hideLoading() } }; xhr.send(JSON.stringify(data)); } function unfilter() { url=/search_year_filter/ var term=document.getElementById("search_meta_data").dataset.term var data={ "year":"unfilter", "term":term, "pgn":1 } filtered_res=post_and_fetch(data,url) } function deactivate_all_bars(){ var yrchart = document.querySelectorAll('.ct-bar'); yrchart.forEach(function(bar) { bar.dataset.active = false bar.style = "stroke:#71a3c5;" }) } year_chart.on("created", function() { var yrchart = document.querySelectorAll('.ct-bar'); yrchart.forEach(function(check) { check.addEventListener('click', checkIndex); }) }); function checkIndex(event) { var yrchart = document.querySelectorAll('.ct-bar'); var year_bar = event.target if (year_bar.dataset.active == "true") { unfilter_res = unfilter() year_bar.dataset.active = false year_bar.style = "stroke:#1d2b3699;" } else { deactivate_all_bars() year_bar.dataset.active = true year_bar.style = "stroke:#e56f6f;" filter_year = chart_data['labels'][Array.from(yrchart).indexOf(year_bar)] url=/search_year_filter/ var term=document.getElementById("search_meta_data").dataset.term var data={ "year":filter_year, "term":term, "pgn":1 } filtered_res=post_and_fetch(data,url) } } function showLoading() { document.getElementById("loading").style.display = "block"; setTimeout(hideLoading, 10000); // 10 seconds } function hideLoading() { document.getElementById("loading").style.display = "none"; } -->