Hydrothermal coupling model of a riparian zone considering heterogeneous heat transfer of soil

To improve the current simulations of hydrothermal exchange in riparian zones that do not take into account heterogeneous heat transfer of soil, this paper constructs a hydrothermal coupling model of riparian zones that includes heterogeneous heat transfer of soil by introducing the soil effective thermal conductivity model on the basis of saturated-unsaturated seepage and porous medium heat transfer theories. This study uses COMSOL software to implement the new method and simulate the hydrothermal coupling model of a riparian zone for different effective thermal conductivity models; the new model is verified by comparing and analyzing prototype observation data of temperature and water level in a riparian zone. The results show that the new model can better reflect the hydrothermal exchange process in a riparian zone than the traditional method that does not consider the heterogeneous heat transfer of the soil. In addition, the simulation of the hydrothermal coupling model based on Johansen's effective thermal conductivity model performs the best, and the simulation results are consistent with previous experimental results. This study can provide technical support for in-depth study of hydrothermal exchange and pollutant migration processes in riparian zones.