【摘要】：不同幾何比尺對(duì)模型水流結(jié)構(gòu)及泥沙運(yùn)動(dòng)特性的比尺效應(yīng)不同,模型沙波相似性也存在差異。首先基于對(duì)泥沙沉速的理論分析,計(jì)算了當(dāng)原型沙粒徑、λ_((γ_s-γ))/γ和η等參數(shù)一定時(shí),滿足起動(dòng)相似所選模型沙沉降速度偏離程度隨不同幾何比尺的變化規(guī)律。計(jì)算結(jié)果顯示:λ_l1時(shí),模型沙沉降速度偏離程度隨著幾何比尺的進(jìn)一步減小而迅速增大;當(dāng)λ_l≥1時(shí),模型沙沉降速度偏離程度隨著幾何比尺的增大表現(xiàn)為先增大后減小,且在幾何比尺為2的附近達(dá)到極大值。為研究沉降速度偏離幅度較大時(shí)模型沙波的相似性及幾何比尺改變時(shí)沙波波高、波長(zhǎng)與原型的偏離特性,設(shè)計(jì)進(jìn)行了λ_l=0.84、1.59和2.06的正態(tài)水槽試驗(yàn),發(fā)現(xiàn)3組模型中的沙波波高、波長(zhǎng)偏差幅度均不大于6%,其中λ_l=0.84的模型沙波偏小,而λ_l=1.59和2.06的沙波偏大。結(jié)合理論分析結(jié)果和水槽試驗(yàn)數(shù)據(jù),得到以下結(jié)論:1)對(duì)于幾何正態(tài)模型,當(dāng)λl1、原型沙與模型沙重率相同時(shí),滿足起動(dòng)相似的模型沙沉降速度偏小,相同水流條件下泥沙落淤速度慢,模型中的沙波波高、波長(zhǎng)均較原型偏小;當(dāng)λ_l≥1時(shí),滿足起動(dòng)相似的模型沙沉降速度偏大,泥沙落淤較快,相應(yīng)模型中沙波波高波長(zhǎng)都較原型偏大。2)若λ_l≥1,模型沙波波高、波長(zhǎng)偏差幅度均不大于6%,即模型沙波波高、波長(zhǎng)的相似性較好。
[Abstract]:The scale effects of different geometric scales on the model flow structure and sediment movement characteristics are different, and the similarity of model sand waves is also different. Based on the theoretical analysis of sediment sedimentation velocity, the variation law of sediment settlement velocity with different geometric scales is calculated when the parameters of prototype sand particle size, 位 _ (緯 -S ~-緯) / 緯 and 畏 are constant. The results show that the deviation degree of model sediment settlement velocity increases rapidly with the further decrease of geometric scale at 位 _ L _ 1, and when 位 _ l 鈮，

本文編號(hào)：2254502