D=pblu(U-u)dy=pbU2d1-)dy =pbu-8 D(x)=TA=bT(x)dx t, (xdx=puB 2d0 Von Ka'rma'n 1921 (1881-1963)0 D b u U u dy ( )  = −   2 =   bU 2 w d U dx    = Von Ka rma n   1921 (1881-1963)  = −   0 2 (1 )dy U u U u bU  = x w x dx U 0 2  ( )   D(x) = w A  = x b w x dx 0  ( )