近临界弯曲比率水槽水流与近床剪应力特性
发布时间：2018-07-15 07:49
【摘要】：床面剪应力诱发了水流垂向上流速分布不稳定性,压力和向心力不均则促使水流形成了弯道二次流.通过试验,研究了近临界弯曲比率(R/B=3)条件下,小宽深比(B/H=2)水槽中水流变化及泥沙输移特性.研究结果表明:二次流强度最大值出现在弯顶区域,床面剪应力最大值出现在弯顶偏凸岸一侧.弯道床面附近,不同层面上的剪应力最大值,从上游到下游先增大后减小;不同平面动力轴线随层面的高度增加而向凹岸偏离.二次流在不同断面形成不同的涡核,在弯道入口附近产生分离而在弯道下游逐步发展,涡核合并,二次流强度在弯顶区达到最大值.最后对二次流和床面剪应力作用下的床面形态结果进行分析.
[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.
【作者单位】： 水利工程仿真与安全国家重点试验室(天津大学);天津大学河流海岸工程泥沙研究所;
【基金】：国家自然科学基金资助项目(51279124,51021004,50979066)~~
【分类号】：TV133
，
本文编号：2123381
[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.
【作者单位】： 水利工程仿真与安全国家重点试验室(天津大学);天津大学河流海岸工程泥沙研究所;
【基金】：国家自然科学基金资助项目(51279124,51021004,50979066)~~
【分类号】：TV133
，
本文编号：2123381
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