完全气体 内能和焓 热力学复习 热力学第一定律 熵及热力学第二定律 等熵关系式 第七章路线图 压缩性定义 无粘可压缩流动的控制方程 总条件的定义 有激波的超音速流动的定性了解
完全气体 内能和焓 热力学复习 热力学第一定律 熵及热力学第二定律 等熵关系式 压缩性定义 无粘可压缩流动的控制方程 总条件的定义 有激波的超音速流动的定性了解 第 七 章 路 线 图
7.3. DEFINITION OF COMPRESSIBILITY (压缩性定义 All real substances are compressible to some greater or lesser extend d. When you squeeze or press on them, their density will change. This is particularly true of gase (所有的真实物质都是可压缩的,当我们压挤 它们时,它们的密度会发生变化对于气体尤 其是这样
7.3. DEFINITION OF COMPRESSIBILITY (压缩性定义) All real substances are compressible to some greater or lesser extend. When you squeeze or press on them, their density will change. This is particularly true of gases. (所有的真实物质都是可压缩的,当我们压挤 它们时,它们的密度会发生变化,对于气体尤 其是这样.)
The amount by which a substance can be compressed is given by a specific property of the substance called the compressibilty, defined below 物质可被压缩的大小程度称为物质的压缩性 Consider a small element of fluid of volume v The pressure exerted on the sides of the element is p If the pressure s increased by an infinitesimal amount d, the volume will change by a negative amoumt d
The amount by which a substance can be compressed is given by a specific property of the substance called the compressibilty , defined below. 物质可被压缩的大小程度称为物质的压缩性. Consider a small element of fluid of volume . The pressure exerted on the sides of the element is p. If the pressure is increased by an infinitesimal amount dp, the volume will change by a negative amount . v dv
t+du FIGURE 73 Defnition of compressibility
By definition, the compressibility is given by (7.33) (7.36 Physically the compressibility is a fractional change in volume of he fluid element per unit change in pressure(从物理上讲,压缩 性就是每单位压强变化引起的流体微元单位体积内的体积 变化
By definition, the compressibility is given by: (7.33) as (7.36) Physically, the compressibility is a fractional change in volume of the fluid element per unit change in pressure.(从物理上讲,压缩 性就是每单位压强变化引起的流体微元单位体积内的体积 变化) dp dv v 1 = − dp d 1 = 1 v =