黏性可压缩流体动力学的物理基础

General Theoretical Basis of Compressible Viscous Flows

作为流体运动纵横分解耦合的物理理论基础,本文首先回顾流体力学运动学和动力学的基本概念与方程,着重阐明黏性与传热效应的必要性及其分子动理学的微观机制,引入系列文章将用到的线性扩散近似以及速度梯度张量的纵横分解、面变形的概念和动量方程的张量拓广.其次强调过程的因果性并将其分为运流型、运流-扩散型、运流波动型三类,以及非线性耦合时的因果性判断.最后回顾物质描述和场描述各自的特点.

As the theoretical basis for the longitudinal-transverse decomposition and coupling of the fluid motion,this article first reviews the fundamental concepts and governing equations of fluid kinematics and dynamics,with emphasis on the necessity of viscosity and heat conductivity along with their microscopic mechanism from gas kinetics.A linear diffusion approximation will be applied throughout this series.Also introduced are the longitudinal-transverse decomposition of velocity gradient tensor,surface deformation tensor,and the tensorial extension of the momentum equation.We then emphasize the causality of a process and classify relevant governing equations to advective,advective-diffusive and advective-wave types.We finally review the Lagrangian and Eulerian descriptions of fluid motion and their respective characteristics.