NUMERICAL ANALYSIS ON THE OCCURRENCE OF THERMAL CONVECTION IN FLOWING SHALLOW GROUNDWATER

Abstract

The occurrence of thermal convection in groundwater could significantly change groundwater
flows, and this phenomena could also alter solute transport. In the case of a shallow groundwater, thermal
convection might affect the surface water quality because it directly interacts with surface waters such as lakes
and marshes. Hence, understanding the conditions that induce thermal convection is important for groundwater
management. In this study, the conditions for the onset and decay of thermal convection in a flowing shallow
groundwater are investigated by conducting numerical experiments. Through the computational analysis using
the attractor reconstruction technique, three flow regime types were found, showing that not only the Rayleigh
number, which is a well-known influential factor, but also the groundwater flow rate affects the flow regime.