Editorial for the Special Issue on Gas Flows in Microsystems

The last two decades have witnessed a rapid development of microelectromechanical systems (MEMS) involving gas microflows in various technical fields [...]

Parallel implementation of multiscale approach to the numerical study of gas microflows

Статья посвящена параллельной реализации многомасштабного подхода для расчета течений газов в микроканалах сложных технических систем. Многомасштабный подход сочетает решения уравнений квазигазодинамики (КГД) и молекулярной динамики (МД). Представлена параллельная реализация подхода, основанная на методах расщепления по физическим процессам и разделения областей. Реализация ориентирована на использование вычислительных систем с центральной и гибридной архитектурами. Разработанные параллельные алгоритмы обладают хорошей масштабируемостью. Полученные результаты подтвердили эффективность разработанного подхода. С его помощью методами МД были получены основные коэффициентные зависимости для КГД-системы, произведен расчет трехмерного течения. This paper is devoted to a parallel implementation of multiscale approach to the numerical study of gas flows in microchannels of complex technical systems. The multiscale approach combines the solutions of quasigasdynamic (QGD) equations and molecular dynamics (MD) equations. The proposed parallel implementation of this approach is based on the method of splitting into physical processes and the domain decomposition method. The implementation is oriented for using computer systems with central and hybrid architectures. The developed parallel algorithms show a good scalability. The obtained results confirm the efficiency of the approach under consideration. This approach was used to find the basic coefficient dependences for the QGD system by MD methods and to study a three-dimensional gas flow numerically.

A Finite-Difference Lattice Boltzmann Approach for Gas Microflows

Finite-difference Lattice Boltzmann (LB) models are proposed for simulating gas flows in devices with microscale geometries. The models employ the roots of half-range Gauss-Hermite polynomials as discrete velocities. Unlike the standard LB velocity-space discretizations based on the roots of full-range Hermite polynomials, using the nodes of a quadrature defined in the half-space permits a consistent treatment of kinetic boundary conditions. The possibilities of the proposed LB models are illustrated by studying the one-dimensional Couette flow and the two-dimensional square driven cavity flow. Numerical and analytical results show an improved accuracy in finite Knudsen flows as compared with standard LB models.