Studies on rarefied gases consider gas flows where the characteristic length or time scale is of the order of the molecular mean-free path or time, respectively. Under such conditions, the gas cannot be treated as continuum, and the molecular properties of the medium must be taken into account. These scenarios prevail in small-scale mechanical systems applications as well as at low-pressure conditions. In marked difference from incompressible flow fields, the coupling between the dynamic and thermodynamic descriptions of rarefied gas flows is prevalent, and may be induced through externally-imposed thermal excitation of a surface. The goal of the present research is to explore the effect of thermal conditions at a solid boundary on heat and mass transfer phenomena in rarefied gases.
The seminar will cover two of the topics studied in my work: (i) the impact of thermal conditions on the acoustic field of a pulsating body at short length and time scales; (ii) nonlinear thermal effects in unsteady shear flows of rarefied gases. In each setup, the analysis combines numerical simulations (based on the direct simulation Monte Carlo method) with limit-case analytical investigations, in an effort to shed light on the coupling between thermal and dynamic phenomena at far-from-equilibrium conditions.
