發(fā)布時間：2018-06-18 18:55

  本文選題：薄壁堰 + 自由出流　； 參考：《西華大學》2017年碩士論文

【摘要】：洪水災害是世界上最嚴重的自然災害之一,其往往分布在人口稠密、農(nóng)業(yè)墾殖度高、江河湖泊集中、降雨充沛的地方,如北半球暖溫帶、亞熱帶。中國、孟加拉國是世界上洪水災害發(fā)生最頻繁的地區(qū),美國、日本、印度和歐洲的洪水災害也較嚴重。我國幅員遼闊,地形復雜,季風氣候顯著,是世界上水災頻發(fā)且影響范圍較廣泛的國家之一。全國約有35%的耕地、40%的人口和70%的工農(nóng)業(yè)生產(chǎn)經(jīng)常受到江河洪水的威脅,并且因洪水災害所造成的財產(chǎn)損失居各種災害之首。從洪澇災害的發(fā)生機制來看,洪水災害具有明顯的季節(jié)性、區(qū)域性和可重復性。我國的洪水災害一般發(fā)生在4-9月。在2016年7月發(fā)生的洪災中,全國有26省(區(qū)、市)1192縣遭受洪澇災害,農(nóng)作物受災面積2942千公頃,受災人口3282萬人,緊急轉移148萬人,因災死亡186人、失蹤45人,倒塌房屋5.6萬間,直接經(jīng)濟損失約506億元。從受災區(qū)域來看,城市受災情況最為嚴重,造成的直接經(jīng)濟損失最大。因此,城市河道防洪是當前我國非常重要的課題。在現(xiàn)在的城市河道防洪系統(tǒng)中,洪水流量的計算尤為重要,而堰是作為重要的流量測定水工建筑物,對此,本文針對目前計算公式中所存在的問題,探討薄壁堰在流量測定中的作用,重點對薄壁堰自由出流進行研究�；趧恿慷ɡ�,從上游水頭與臨界水頭,雷諾數(shù)與上游水頭、流量以及流量系數(shù)這幾個因素的綜合評價分析,采用最小二乘法和圖解法,并通過方差分析得到了新自由出流計算公式。該研究結果適用性強,流量系數(shù)計算比目前計算公式更準確,更能適應當前極端氣候下得薄壁堰自由出流計算。
[Abstract]:Flood disaster is one of the most serious natural disasters in the world, which is often distributed in places with dense population, high degree of agricultural reclamation, concentrated rivers and lakes and abundant rainfall, such as warm temperate zone in the northern hemisphere and subtropical zone. China and Bangladesh have the most frequent floods in the world, as are the United States, Japan, India and Europe. Our country is one of the countries with large territory, complicated topography and remarkable monsoon climate. About 35% of the cultivated land in China, 40% of the population and 70% of industrial and agricultural production are often threatened by river floods, and the property losses caused by flood disasters rank first among all kinds of disasters. According to the occurrence mechanism of flood disaster, flood disaster has obvious seasonal, regional and repeatability. The flood disaster in China generally occurred in April and September. In the floods that occurred in July 2016, 26 provinces (districts, cities and counties) were affected by floods. The crops affected an area of 2,942 thousand hectares, 32.82 million people were affected, 1.48 million people were urgently transferred, 186 people were killed and 45 people were missing as a result of the disaster. Collapse of 56000 houses, direct economic losses of about 50.6 billion yuan. From the disaster area, urban disaster is the most serious, resulting in the largest direct economic losses. Therefore, urban river flood control is a very important subject in our country. In the present urban river flood control system, the calculation of flood discharge is particularly important, and the Weir is used as an important flow measurement hydraulic structure. In view of this, this paper aims at the problems existing in the present calculation formula. The function of thin-walled Weir in flow measurement is discussed, and the free discharge of thin-walled Weir is studied. Based on momentum theorem, the least square method and graphic method are used to evaluate and analyze the factors of upstream water head and critical head, Reynolds number and upstream water head, flow rate and flow coefficient. The new formula of free discharge is obtained by variance analysis. The results of this study are more suitable for the calculation of free discharge of thin-walled Weir in extreme climate than the current formula.
【學位授予單位】：西華大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TV131.6

【參考文獻】

相關期刊論文 前3條

1 巨正平;郭廣禮;張書畢;齊建偉;;最佳曲線擬合[J];江西科學;2009年01期

2 王仲發(fā);水工模型試驗中薄壁堰縮尺效應分析[J];山東農(nóng)業(yè)大學學報(自然科學版);2002年04期

3 郭覺新;推求堰流公式新法[J];土木工程學報;1957年03期

，

本文編號：2036525