Three-Dimensional Thermal Groundwater Analysis by Localized Meshless Method and Method of Characteristics

This paper aims to develop an accurate and efficient numerical model for three-dimensional transient thermal groundwater flow problems. The modified Richards equation and heat transport equation are considered to govern the thermal groundwater flows. For modeling water flows in the subsurface saturated-unsaturated porous media, we combined the method of characteristics (MOC) and a meshless localized radial basis function collocation method (LRBFCM). In order to implement the MOC scheme, the modified Richards equation is reformulated to an advection form and then computed by the particle tracking technique via MOC. We will then solve the heat equation and remaining terms of the temporal Richards equation by the LRBFCM. Seven benchmark subsurface flow problems with and without temperature effects are simulated and discussed to verify the feasibility and efficiency of this novel three-dimensional (3D) numerical model.