dmy df )in] obu dy-pbhU/2 ann streamline P Momentum equation U ∑F=「m?- phu2° CV ∑F=D(g)→D=mbU2-mbbh Continuity:phu= pbudy=>pbhU2= pbuUdy D=pbl(U-u)hy速度积分法求阻力 08 Momentum equation: F D drag = − ( ) Continuity: 0 D b u U u dy ( )  = −   [( ) ( ) ] out in dmV dmV dmV dt dt dt = − 2 0 2 bu dy bhU  = −  2 0 2 F bu dy bhU  = −      = −    0 2 2 D bhU bu dy  =    0 bhU budy   =    0 2 bhU buUdy CV x y h U P d streamline o 速度积分法求阻力