Гидродинамика

А NOTE ON THE MOTION OF VORTEX RINGS 419 where M i s tbe strength of all the ring-s, and that due to mo ­ tions o f t h e third group is . H e n c e all points within the t ho - 4 - A roid h a v e a common velocity i n t h e direction of the axis of t he t ho r o i d - ^ 2~A I S 8 a and t h e w h o l e mass of fluid wi t h i n t h e thoroid is in a motion of t r a n s l a t i o n .