u rlar a0 az az a ee=Gee 0 任一点的涡量都垂直于过该点和对称轴的平面(子午面) (2vn90=2n(u4+g人?分 DQ (+l1++11)(22en) Dt r06 ue r06 06 Do Q Dt U)=01 ( ) 0 ( )( ) ( ) ( ) ( ) 0 r z r z r z r z r r r z z r r r e re e u u e e r r z z r u u D D u u u e e Dt t r r z Dt u e u u e u e u u e r r r r D u e Dt r D                            = = − =             = + + +  =             = = + = =      − = 任一点的涡量都垂直于过该点和对称轴的平面（子午面）, ( ) 0 Dt r  =