b = velocity coefficient cp = specific heat f = nondimensional stream function K = nonequilibrium parameter Kn = Knudsen number k = thermal conductivity l = slip length M = Mach number m = flow exponent n = distance in the normal direction P = pressure Pr = Prandtl number Re = Reynolds number T = temperature U = external x velocity u = x velocity v = y velocity x = position in the flow directio...

A blended drag coefficient model is constructed using a series of empirical relations based on Reynolds number, Mach and Knudsen number. When validated against experiments, the produces matching values with standard deviation error 2.84% maximum 11.87%. The used in Lagrangian code which coupled to hypersonic aerothermodynamic CFD code, particle velocity trajectory are experimental results. comp...

We present a multi-scale lattice Boltzmann scheme, which adaptively refines particles' velocity space. Different sets of lower and higher order are consistently efficiently coupled, allowing us to use the higher-order model only when where needed. This includes regions high Mach or Knudsen numbers. The coupling procedure discrete consists either projection populations onto lower-order lifting B...

In the present study, a compact analytical model is developed to determine the pressure drop of fully-developed, incompressible, and constant properties slip-flow through arbitrary cross-section microchannels. An averaged firstorder Maxwell slip boundary condition is considered. Introducing a relative velocity, the difference between the bulk flow and the boundary velocities, the axial momentum...

The temperature driven gas flow in a two-dimensional finite length microchannel and a cylindrical tube are studied numerically with the goal of performance optimization of a nanomembrane-based Knudsen compressor. The numerical solutions are obtained using direct simulation Monte Carlo method and discrete ordinate method for BGK model kinetic equation in a wide range of Knudsen numbers from 0.05...

We present predictions for the statistical error due to finite sampling in the presence of thermal fluctuations in molecular simulation algorithms. Specifically, we establish how these errors depend on Mach number, Knudsen number, number of particles, etc. Expressions for the common hydrodynamic variables of interest such as flow velocity, temperature, density, pressure, shear stress, and heat ...