本文選題：寬窄相間河道 + 三維流場(chǎng)��； 參考：《長(zhǎng)江科學(xué)院院報(bào)》2016年08期

【摘要】：為了研究山區(qū)河流寬窄相間河段不同流量下水流結(jié)構(gòu)特性,以雅安寶興河上游河段為研究對(duì)象,概化實(shí)際河道,并建立三維水流計(jì)算模型。結(jié)果表明:1小流量下,窄段上游無明顯壅水現(xiàn)象,寬窄相間河道顯現(xiàn)出與順直河道相似的特性,隨著流量的增加,窄段上游壅水劇烈,寬段到窄段沿程斷面平均流速呈現(xiàn)"增加—相對(duì)穩(wěn)定—驟減—相對(duì)穩(wěn)定—增加"的分布規(guī)律;2受河寬、壅水和回流影響,不同流量工況下寬段橫斷面的水流特性分布較窄段更加復(fù)雜,且在寬段的壅水區(qū)與非壅水區(qū)流速分布規(guī)律差異亦較大;3不同流量狀況下,寬段床面剪切力劇烈變化將造成卵石沿程運(yùn)動(dòng)的不連續(xù)性,寬段河床呈現(xiàn)周期性往復(fù)發(fā)展的復(fù)歸性變形,從而維持了寬段河床結(jié)構(gòu)的穩(wěn)定,而在窄段,河道在較大的床面剪切力長(zhǎng)期作用下,形成了與周圍環(huán)境相適應(yīng)的河床結(jié)構(gòu),以消耗窄段較大的水流能量,從而保護(hù)河床的穩(wěn)定。
[Abstract]:In order to study the characteristics of flow structure under different discharge in mountainous rivers, the upper reaches of Ya'an Baoxing River are taken as the research object, the actual river channels are generalized, and a three-dimensional flow calculation model is established. The results show that there is no obvious backwater in the upper reaches of the narrow section under the small flow of 1: 1, and the characteristics of the broad-narrow interphase channel are similar to those of the straight channel. With the increase of the discharge, the backwater in the upstream of the narrow section is violent. The distribution law of the average velocity along the section from wide to narrow section is "increasing-relatively stable-plummeting-relatively stable-increasing", which is affected by river width, backwater and backflow. Under different flow conditions, the distribution of flow characteristics in wide cross-section is more complex than in narrow section, and the velocity distribution law of backwater area and unbackwater area in wide section is different from that in unbackwater section. The sharp change of shear stress on the wide section of bed will cause discontinuity of pebble movement along the path, and the bed of wide section will exhibit periodic reciprocating deformation, thus maintaining the stability of the structure of the wide section of the river bed, while in the narrow section, the stability of the bed structure will be maintained. Under the long-term action of large shear stress on the bed surface, the river bed structure adapted to the surrounding environment is formed to consume the large flow energy of the narrow section and thus to protect the stability of the river bed.
【作者單位】： 四川農(nóng)業(yè)大學(xué)水利水電學(xué)院;
【分類號(hào)】：TV133
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本文編號(hào)：1917046