نتایج جستجو برای: Time development of scour depth
تعداد نتایج: 21355274 فیلتر نتایج به سال:
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...
today, scouring is one of the important topics in the river and coastal engineering so that the most destruction in the bridges is occurred due to this phenomenon. whereas the bridges are assumed as the most important connecting structures in the communications roads in the country and their importance is doubled while floodwater, thus exact design and maintenance thereof is very crucial. f...
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 ...
The most important causes of bridge failure are local scour. In this study, laboratory experiments were conducted to investigate the effectiveness of slot as a protection device in reduction of depth of scour at cylindrical piers under clear water flow conditions. The development time of scour depth at the circular pier with and without a slot as a protection device was conducted. The experimen...
many experimental studies have been conducted on development of the scour hole as a result of vertical jet impaction. research has shown that aeration of the nappe flow in the model is much weaker than that in the prototype. therefore, the influence of aeration on scour holes needs further study. experimental investigation of the effects of air entrainment and tail water depth on the scour hole...
An experimental approach was carried out to study the time development and extension of scouring around a circular pier protected by a collar. The experiments included the study of scouring around an unprotected pier as well as the pier protected with collars located at different levels. Width of collars was 3 times the pier diameter. It was found that with collars, though the scour depth and t...
testing plays a vital role in any language teaching program. it allows teachers and stakeholders, including program administrators, parents, admissions officers and prospective employers to be assured that the learners are progressing according to an accepted standard (douglas, 2010). the problems currently facing language testers have both practical and theoretical implications but the first i...
Experimental studies to investigate the depth of the scour conducted at a side-weir intersection located at the 180 curved flume which located Hydraulic Laboratory of Yıldız Technical University, Istanbul, Turkey. Side weirs were located at the middle of the straight part of the main channel. Three different lengths (25, 40 and 50 cm) and three different weir crest height (7, 10 and 12 cm) of t...
Scour is a phenomenon that occurs as a result of natural erosion by ground water flow and transport of seabed material. In this research, scour around the legs of marine structures is simulated using the FLOW3D.V.9.3™ commercial software. The general scour model consists of two components, namely, the lift and thrust forces. The drag force, that is inserted to the structure, is a combination of...
the effect of grain size, tailwater depth and grain froude number on local scour caused by submerged horizontal jets issuing below a sluice gate was investigated. noncohesive sediments with two gradations downstream of a horizontal apron were used in the experiments. the experiments were carried out at different inflow froude numbers and a range of tailwater depth from low to high submergence. ...
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