Thermal transpiration is a rarefied gas flow driven by a wall temperature gradient and is a promising mechanism for gas pumping without moving parts, known as the Knudsen pump. Obtaining temperature measurements along capillary walls in a Knudsen pump is difficult due to extremely small length scales. Meanwhile, simplified analytical models are not applicable under the practical operating condi...

We consider phase separation in a nonequilibrium Bose gas with an attractive interaction between particles. Using numerical integrations on a lattice, we show that the system evolves into a state that contains drops of a Bose-Einstein condensate suspended in uncondensed gas. When the initial gas is sufficiently rarefied, the rate of formation of this quantum dew scales with the initial density ...

The paper presents a parallelization technique for the finite pointset method, a numerical method for rarefied gas flows. First we give a short introduction to the Boltzmann equation, which describes the behaviour of rarefied gas flows. The basic ideas of the finite pointset method are presented and a strategy to parallelize the algorithm will be explained. It is shown that a static processor p...

A pilot model of the hypersonic rarefied wind-tunnel (HRWT) has been developed and its flow characteristics have been measured. The HRWT consists of a gas heater which produces an increase in working gas temperature, an expansion nozzle with a large expansion ratio, a vacuum chamber as the test section, and an evacuation system with high exhaust velocity to allow a continuous operation at low a...

The present lecture is devoted to experimental and theoretical modelling for rarefied aerodynamics. General features of experimental studies in rarefied flows are discussed. Experimental facilities designed in Saint Petersburg State University for rarefied aerodynamics and plasma flow control are described. Several theoretical models for non-equilibrium reacting flows in the slip regime are pre...

For gas flows in microchannels, slip motion at the solid surface can occur even if the Mach number is negligibly small. Since the Knudsen number of the gas flow in a long microchannel can vary widely and the Navier-Stokes equations are not valid for Knudsen numbers beyond 0.1, an alternative method that can be applicable to continuum, slip and transition flow regimes is highly desirable. The la...