20071518
20071518 3
,
() (turbulent flow). ( ) () . (laminar flow) () , . .()(ideal fluid) . . . .(steady flow) . , +x 3m/s . dv/dt = 0 . ( x,y,z ) . , T ,
. . , 3.1 .
, , . , , v . .
(unsteady flow, ) . , .
, .(uniform flow) ( ) .
. . () . . (nonuniform flow) . () . () . ()(streamline) (). . () x,y,z u,v,w q .
. , .
. () . (3.1.3) . (3.1.3) . , . . , ()(())(path of a particle; path line) . , . ()(() . . ()(streak line) . . .
. .
. .1. Newton - .2. , 3. 1, 2 4. ; , 0 , 0 (() ). Newton . 3.3 .
3.3 () t xyz t . . . xyz . t+t . . N t (, ) . N . 3.3(b) , t+t . t 3.3(a) . t N .
t N . t 0 . dN/dt . 1 , t 0 , t+t N , 3 t N . .
14 (3.2.6), N (xyz ) N N () . , .
3 .