C4.2边界层概念 例1:空气运动粘度v=1.410-5m2/s

(1)判断该流场是否存在速度势,若存在请确定其形式并画等势线图 (2)判断该流场是否存在流函数。若存在请确定其形式并画流线图;

量纲齐次性原理 同一方程中各项的量纲必须相同。用基本量纲的幂次式表示时, 每个基本量纲的幂次应相等,称为量纲齐次性

4.1流体方程的随体导数 4.2积分形式的连续性方程 输运公式可用于任何分布函数n,如密度分布、动量分布、能量分布等

B3.1微分形式的质量守恒方程 B3.1.1流体运动的连续性原理 根据质量守恒定律,不可压缩流体流进控制体的质量应等于流出控制体的质量,称其为流体运动的连续性原理。由哈维发现的人体血液循环理论是流体连续性原理的例证:

1分类 2比较

Chapter 4 Differential Relations For Viscous Flow 4.1 Preliminary Remarks Two ways in analyzing fluid motion (1)Seeking an estimate of gross effects over a finite region or control volume. Integral ()Seeking the point-by-point details of a flow pattern by analyzing an infinitesimal region of the flow

When is a flow compressible? compressible flow differs from an incompressible one in that significant change happens in the density

Boundary layer(边界层) Although frictional effects in slightly viscous fluid are indeed present, they are confined to a thin layer near the surface of the body, and the rest of the flow can be considered inviscid. (1904, Prandt/)

Properties of Pressure Vertical to the surface and point into it. At any point, pressure is independent of orientation