地下水污染物迁移数值模拟分析课件.ppt

1、Dispersive Transport&Advection-dispersion Equation(ADE)C0C0Advection onlyAdvection&DispersiontCCvxii)(v=q/Assuming particles travelat same average linearvelocity v=q/In fact,particles travel at differentvelocities vq/or v DdD represents dispersion Dd represents molecular diffusionzcDycDxcDfzcDycDxcD

2、fzcDycDxcDfzzzyzxDzyzyyyxDyxzxyxxDxIn a 3D flow field it is not possible to simplify the dispersiontensor to three principal components.In a 3D flow field,we must consider all 9 components of the dispersion tensor.The definition of the dispersion coefficient is more complicated for 2D or 3D flow.See Zheng and Bennett,eqns.3.37-3.42.Dx=xvx+Dd Dy=yvx+Dd Dz=zvx+Dd Recall,that for1D uniform flow:General form of the ADE:Expands to 9 termsExpands to 3 terms(See eqn.3.48 in Z&B)Effect of longitudinal and transverse dispersivities on the plume configurationFigure 3.24.from Zheng&Bennett