Gravity-induced modulation of negative differential thermal resistance in fluids.

Abstract

We investigate how gravity influences negative differential thermal resistance (NDTR) in fluids modeled by multiparticle collision dynamics. In the integrable case, we derive the heat flux formula for the system exhibiting the NDTR effect, and show that by introducing a gravity along the direction of the thermodynamic force, the temperature difference required for the occurrence of NDTR can be greatly reduced. Meanwhile, we also demonstrate that the heat-bath-induced NDTR mechanism-originally found to be applicable only to weakly interacting systems-can now operate in systems with stronger interactions due to the presence of gravity, and further remains robust even in mixed fluids. These results provide insights into heat transport and establish a theoretical foundation for designing fluidic thermal devices that harness the NDTR effect under gravity.