复习第二章知识: Control surface S S Control volume V Finite control volume moving Finite control volume with the fluid such that the fixed in space with the same fluid particles are al ways nuid moving through in the same control volume
复习第二章知识：
Volume d y d v
m= DvA Mass flux A(edge view) y dt
m = Vn A Vn A m = = Mass flux
ds ds dv
Continuity(连续方程) Physical principle: mass can be neither created nor destroved let mass flow out of time rate of decrease of control volume mass inside control volume V through surface S 通过控制体表面S流出控制体的净质量流量=控制体内的质量减少率 pdv+Hpv ds=0 (7.39
1. Continuity(连续方程） Physical principle: mass can be neither created nor destroyed Net mass flow out of time rate of decrease of control volume = mass inside control volume V through surface S 通过控制体表面S流出控制体的净质量流量＝控制体内的质量减少率 + = S dv V dS t 0 (7.39)