剛性非浸沒式植被對彎道水流特性的影響
發(fā)布時間：2018-07-24 10:10
【摘要】：該文采用180°U形矩形截面彎道玻璃水槽模擬天然彎道河流,運(yùn)用聲學(xué)多普勒流速儀(acoustic doppler velocimeter,ADV)研究剛性非浸沒式植被(密度4.47%)對彎道水流縱向流速分布,橫向環(huán)流及湍流動能(turbulence kinetic energy,TKE)的影響。實(shí)驗(yàn)結(jié)果表明,當(dāng)水槽流量較小時,植被對水流的阻礙作用較小,由流速降低而導(dǎo)致的水深增加現(xiàn)象不明顯,當(dāng)水槽流量增大時候,植被對水位的抬升現(xiàn)象明顯;水流受植被"阻滯"作用,彎道處縱向流速沿水深分布不再服從"對數(shù)型"分布規(guī)律,且原本水流受彎道作用后呈現(xiàn)的"上減下增"效果也消失;植被加快了最大流速區(qū)向凸岸轉(zhuǎn)移,到達(dá)彎道出口時,最大流速區(qū)逐漸轉(zhuǎn)移至斷面中部區(qū)域;在植被的影響下,各斷面彎道環(huán)流消失;植被會加劇水流紊動效應(yīng),導(dǎo)致湍動加劇,TKE增大。上述實(shí)驗(yàn)結(jié)論將增進(jìn)研究者對植被對彎道水流特性影響的理解,同時也為泥沙疏浚,河道生態(tài)系統(tǒng)恢復(fù)提供指導(dǎo)。
[Abstract]:In this paper, a 180 擄U-shaped rectangular section bend glass flume is used to simulate the natural bend river, and the acoustic Doppler velocimeter (acoustic doppler velocimeter) is used to study the longitudinal velocity distribution of rigid unsubmerged vegetation (density 4.47%). The effects of transverse circulation and turbulent kinetic energy (turbulence kinetic energy TKE). The experimental results show that when the flow rate of the flume is small, the effect of vegetation on the water flow is small, and the increase of the water depth caused by the decrease of the flow velocity is not obvious, and when the flow rate of the flume increases, the vegetation uplift the water level is obvious. The water flow is blocked by vegetation, the vertical velocity distribution along the depth of the bend is no longer obeyed the "logarithmic" distribution rule, and the effect of "up, decreasing, decreasing and increasing" after the original flow is affected by the bend is also disappeared. Vegetation speeds up the maximum velocity zone to the convex bank, and when it reaches the exit of the bend, the maximum velocity area gradually shifts to the middle of the section. Under the influence of vegetation, the circulations of each section of the bend disappear, and the vegetation will aggravate the turbulent effect of the flow. The increase of TKE is caused by turbulence. The above conclusions will improve the understanding of the effects of vegetation on the flow characteristics of bends and provide guidance for sediment dredging and restoration of river ecosystem.
【作者單位】： 浙江大學(xué)海洋學(xué)院;
【基金】：國家自然科學(xué)基金(11672267)~~
【分類號】：TV131.3
，
本文編號：2141039
[Abstract]:In this paper, a 180 擄U-shaped rectangular section bend glass flume is used to simulate the natural bend river, and the acoustic Doppler velocimeter (acoustic doppler velocimeter) is used to study the longitudinal velocity distribution of rigid unsubmerged vegetation (density 4.47%). The effects of transverse circulation and turbulent kinetic energy (turbulence kinetic energy TKE). The experimental results show that when the flow rate of the flume is small, the effect of vegetation on the water flow is small, and the increase of the water depth caused by the decrease of the flow velocity is not obvious, and when the flow rate of the flume increases, the vegetation uplift the water level is obvious. The water flow is blocked by vegetation, the vertical velocity distribution along the depth of the bend is no longer obeyed the "logarithmic" distribution rule, and the effect of "up, decreasing, decreasing and increasing" after the original flow is affected by the bend is also disappeared. Vegetation speeds up the maximum velocity zone to the convex bank, and when it reaches the exit of the bend, the maximum velocity area gradually shifts to the middle of the section. Under the influence of vegetation, the circulations of each section of the bend disappear, and the vegetation will aggravate the turbulent effect of the flow. The increase of TKE is caused by turbulence. The above conclusions will improve the understanding of the effects of vegetation on the flow characteristics of bends and provide guidance for sediment dredging and restoration of river ecosystem.
【作者單位】： 浙江大學(xué)海洋學(xué)院;
【基金】：國家自然科學(xué)基金(11672267)~~
【分類號】：TV131.3
，
本文編號：2141039
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