發(fā)布時(shí)間：2018-07-15 07:49

【摘要】：床面剪應(yīng)力誘發(fā)了水流垂向上流速分布不穩(wěn)定性,壓力和向心力不均則促使水流形成了彎道二次流.通過試驗(yàn),研究了近臨界彎曲比率(R/B=3)條件下,小寬深比(B/H=2)水槽中水流變化及泥沙輸移特性.研究結(jié)果表明:二次流強(qiáng)度最大值出現(xiàn)在彎頂區(qū)域,床面剪應(yīng)力最大值出現(xiàn)在彎頂偏凸岸一側(cè).彎道床面附近,不同層面上的剪應(yīng)力最大值,從上游到下游先增大后減小;不同平面動力軸線隨層面的高度增加而向凹岸偏離.二次流在不同斷面形成不同的渦核,在彎道入口附近產(chǎn)生分離而在彎道下游逐步發(fā)展,渦核合并,二次流強(qiáng)度在彎頂區(qū)達(dá)到最大值.最后對二次流和床面剪應(yīng)力作用下的床面形態(tài)結(jié)果進(jìn)行分析.
[Abstract]:The bed shear stress induces the instability of the vertical flow velocity distribution, and the uneven pressure and centripetal force promote the formation of the secondary flow in the bend. Under the condition of near critical bending ratio (R / B ~ (3), the characteristics of water flow and sediment transport in a water tank with a small ratio of width to depth (B / H ~ (2) are studied. The results show that the maximum of secondary flow intensity appears in the curved top region and the maximum shear stress of the bed surface appears on the side of the convex bank of the curved top. Near the curved bed surface, the maximum shear stress of different plane increases first from upstream to downstream and then decreases, and the different plane dynamic axes deviate to the concave bank with the increase of the height of the plane. The secondary flow forms different vortex cores in different sections and separates near the entrance of the bend and develops gradually in the lower reaches of the bend. The vortex core merges and the secondary flow intensity reaches the maximum in the curved top region. Finally, the results of bed surface morphology under the action of secondary flow and bed shear stress are analyzed.
【作者單位】： 水利工程仿真與安全國家重點(diǎn)試驗(yàn)室(天津大學(xué));天津大學(xué)河流海岸工程泥沙研究所;
【基金】：國家自然科學(xué)基金資助項(xiàng)目(51279124,51021004,50979066)~~
【分類號】：TV133
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本文編號：2123381