Summarization of chapter 4 The Acceleration Field of a fluid(加速度) (.V Nonlinear terms Local acceleration Convective acceleration a ≠0 unsteady ≠0 nonuniform dt d a Substantial material derivative +(VV) Dt at 随体(物质、全)导数Summarization of Chapter 4 • The Acceleration Field of a Fluid(加速度) V V t V a     + ( )   = Local acceleration unsteady 0 t    Convective acceleration nonuniform 0 i x    Nonlinear terms ( ) D V Dt t  = +   Substantial (Material) derivative 随体（物质、全）导数