Thermal Wall Model Effect on the Lid-Driven Nanocavity Flow Simulation using the Molecular Dynamics Method

Abstract

An accurate molecular dynamics simulation of the nanocavity flow cannot be achieved without considering correct thermal treatments for the molecules both distributed in the flow and located at the cavity walls and without including their interactions correctly. In this study, we specify constant temperature at the nanocavity vertical walls; however, we examine three different thermal wall models, including a rigid wall, a controlled-temperature flexible wall, and a noncontrolled-temperature flexible wall, to model the horizontal wall behaviors. Comparing the results of these three models with each other, it is possible to evaluate the effect of wall model on the resulting temperature and velocity field behaviors. The results indicate that the velocity field is not affected that much using these three different wall models; however, they predict different temperature fields. We show that the differences are mainly due to different characteristics of these three thermal wall models in absorbing, transferring, and dissipating the heat generated by the viscous effects via the wall–fluid molecule interactions.