(1)当流体做平面流动时 )k=_k ay az a (Q2. V)u=Q2-(ui +v=0 az 0 Dt (2)当流体作轴对称流动时 取圆柱坐标系,Z沿对称轴 0(1). = ( ) ( ) ( ) 0 0 (2). , Z 0, 0 z z z i j k v u k = k x y z x y u v 0 u ui vj z D Dt u        = −          =  + =   =  = =  当流体做平面流动时 当流体作轴对称流动时 取圆柱坐标系 沿对称轴