Transverse dispersion has been studied in the literature less than longitudinal dispersion, especially in porous media with fine and very fine sand. In this research, an experimental and numerical procedure is introduced to accurately determine dispersivity coefficients. Accordingly, three-dimensional tracer experiments (transient and steady state) are conducted in a relatively large sandbox (158 cm × 160 cm in plane and height of 70 cm), filled with a fine sand soil (D₅₀ = 0.17 mm). The effects of different hydraulic heads and several injection concentrations are considered in the experiments. The transverse and longitudinal dispersivity are determined accurately by fitting numerical simulations to the steady-state and transient sandbox experiments, respectively. According to the results, the transverse dispersivity ranges between 0.0025 and 0.06 cm, while the longitudinal dispersivity varies from 0.15 to 0.75 cm. In addition, the ratio of transverse dispersivity to longitudinal dispersivity varies between 0.017 and 0.1, based on hydraulic gradients and solute concentrations. It was observed that the transverse and longitudinal dispersivity coefficients increase as the hydraulic gradient rises. Finally, the sensitivity analysis results show that the simulated depth–concentration curves at the steady-state condition remain approximately constant with the reasonable variations in the longitudinal dispersivity coefficient, the hydraulic conductivity, and the porosity.

文献中研究的横向弥散小于纵向弥散，尤其是在具有细砂和极细砂的多孔介质中。在这项研究中，引入了实验和数值程序来准确确定色散系数。因此，三维示踪实验（瞬态和稳态）在一个相对较大的沙箱（平面 158 cm × 160 cm，高度 70 cm）中进行，填充细砂土（D ₅₀ = 0.17 毫米）。实验中考虑了不同水头和几种注入浓度的影响。通过将数值模拟分别拟合到稳态和瞬态沙箱实验，可以准确地确定横向和纵向色散率。根据结果​​，横向色散率在 0.0025 到 0.06 cm 之间，而纵向色散率在 0.15 到 0.75 cm 之间变化。此外，根据水力梯度和溶质浓度，横向弥散率与纵向弥散率的比率在 0.017 和 0.1 之间变化。据观察，横向和纵向弥散系数随着水力梯度的上升而增加。最后，