摘要
在适体同位网格中采用非正交曲线坐标系下的三维k-ε-k_p固液两相双流体湍流模型研究弯道内水流和悬浮泥沙运动,主要计算了试验室S型水槽内清水流动的三维流场、120°弯道内水沙两相流动中底沙与底流的运动轨迹以及S型水槽内水沙两相流动的两相流场和泥沙浓度场.对于S型水槽内清水流动,数值结果与试验结果吻合良好.120°弯道内水沙两相流动中固液两相的运动轨迹在弯道直线段基本重合,在弯道内泥沙轨迹逐步偏离水体轨迹,其偏离程度随泥沙粒径增大而增大.从S型水槽内水沙两相流动计算结果中发现泥沙纵向流速在壁面附近比水流纵向速度大,在远离壁面区域比水流纵向速度小;弯道内泥沙横向流速比水流横向流速小;垂向流速在直线段和泥沙沉速相当,在弯道内受螺旋水流影响而变化;两相流速差别随泥沙粒径增大而变大;泥沙浓度呈现下浓上稀的分布,在弯道内横向断面上呈现凸岸大凹岸小的分布,泥沙浓度随泥沙粒径增大而减小.
Sediment flow and transport in natural rivers are of considerable interest in the field of river engineering. Generally, there are many channel bends in natural rivers. The flow characteristics and sediment movement are much more complex in channel bends than in straight channels. In order to study the developmeat of water-sediment movement in channel bend, a three-dimensional k-s-kp solid-liquid two-phase two-fluid turbulence （STTT） model in curvilinear coordinates is solved numerically with a finite-volume method on an adaptive grid. The κ-ε-κp STTT model was introduced by Zhou and it consists of a Boussinesq expression with scalar viscosity coefficients to model STTT Reynolds stresses and particle turbulence flux. The water flow in an S-shaped flume was first used to verify liquid-phase model and the velocities of water flow were well reproduced by the model. The secondary flow has different magnitude along the S-shaped flume. Then the model was used to calculate the movements of water and sediment in a 120° channel bend. From both experimental data and numerical results, it was shown that the sediment shares the same streamlines of water in the straight zone and deviates from the streamlines of water at the channel bend. The deviation increases with the increase of sediment particle diameters. The numerical results of solid-liquid two-phase flow in an S-shaped flume have shown that the longitudinal velocities of solid-phase are bigger than those of liquid-phase near wails and smaller than those of liquid-phase in other zones, while the transverse velocities of solid-phase are smaller than those of liquid-phase, and the vertical velocities are almost equal to fall velocities of sediments in straight sections and change much in the bends under the action of helical flows. In addition, the concentration of sediment is bigger in the bottom than that in the surface and also bigger in the inner bank of the S-shaped flume than that in the outer bank.
出处
《力学学报》
EI
CSCD
北大核心
2009年第3期318-328,共11页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然科学基金重点项目(50839001)
国家重点基础研究发展计划项目(2005CB724202)
国家自然科学基金项目(50779006)资助~~
关键词
自适应网格
三维κ-ε-κp模型
固液两相流
双流体模型
弯道
悬沙
流线
adaptive grid, three dimensional k-s-kp model, liquid-particle flows, two-fluid model, channel bends, suspended sediment, streamlines
