CAJ | 학술논문

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.
문동수류중점성니사서응침강대하구해안점성니사수송과정기착십분중요적작용.건립료균균각향동성문류중점성니사서응침강적삼유격자파이자만수학모형,모의불동문동전절솔대점성니사서응과정적영향.모의결과표명:수착문동전절솔적증가,계산구역내서단형성소수적시간선감소후증가,점성니사침강속도야정현선감소후증대적추세,전절솔적전절점재200s-1좌우,여이유관측결과일치.모의결과반영료저강도수체문동대서응유촉진작용이고강도수체문동대서응유억제작용.
The flocculation and settling of cohesive sediment in turbulence play an important role on the co?hesive sediment transport in estuaries and coastal waters. A three-dimensional numerical model of settling and flocculation of cohesive sediment in the homogenous isotropic turbulence using lattice Boltzmann meth?od is developed to investigate the effects of turbulence on the flocculation phenomena of cohesive sediment. It can be seen that with increasing shear rate the start time of the floc formation will be earlier firstly and then be later. Furthermore,it also can be concluded that with increasing shear rate the settling velocity of flocs first increases,then decreases. The turning point of shear rate is 200s-1,which is consistent with the observation. Simulation results show that the low turbulent shear rates have role in promoting on floccula?tion processes and the opposite trend at high shear rates properly.