Temperature Profiles due to Groundwater Flow in a Subsurface Porous Medium with a Heat Convective Boundary

The temperature in subsurface porous media (i.e., subsurface temperature) has been popularly treated as a natural tracer of groundwater flow. Several previous studies usually neglected the thermal boundary effects to build simple geothermal models for simulating the subsurface temperature. Although a few studies considered the thermal boundary effects, their models considered the thermal boundaries under either specific-temperature or specific-heat-flux conditions. However, these models are expectedly inapplicable to the cases of subsurface porous media with convective thermal boundary conditions. This study hence proposes a heat-transport model for describing the subsurface temperature induced by a heat convective boundary. The model is composed of a heat conduction-advection equation subject to a convective boundary condition at the bottom of a porous medium. The study results show how the convective boundary effects influence he subsurface temperature and indicate the effects are dominated by some parameters, including the medium thicknesses, medium thermal conductivity, heat transport coefficient, and groundwater flux.