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紊动水流中黏性泥沙絮凝沉降对河口海岸黏性泥沙输送过程起着十分重要的作用。建立了均匀各向同性紊流中黏性泥沙絮凝沉降的三维格子玻尔兹曼数学模型,模拟不同紊动剪切率对黏性泥沙絮凝过程的影响。模拟结果表明:随着紊动剪切率的增加,计算区域内絮团形成所需的时间先减少后增加,黏性泥沙沉降速度也呈现先减小后增大的趋势,剪切率的转折点在200s-1左右,与已有观测结果一致。模拟结果反映了低强度水体紊动对絮凝有促进作用而高强度水体紊动对絮凝有抑制作用。
The flocculation and sedimentation of viscous sediments in turbulent water plays an important role in the transport of viscous sediments in estuarine and coastal waters. A three-dimensional Lattice Boltzmann mathematical model of cohesive sediment flocculation in homogeneous isotropic turbulence was established to simulate the effect of different turbulent shear rates on the flocculation of cohesive sediments. The simulation results show that with the increase of turbulent shear rate, the time required for the formation of flocs in the calculation area first decreases and then increases, and the sedimentation speed of viscous sediments also decreases first and then increases. The shear rate The turning point is around 200s-1, consistent with the previous observations. The simulation results show that the turbulence of low-intensity water promotes the flocculation while the turbulence of high-intensity water can inhibit the flocculation.