Гидродинамика

ON SUBSTITUTION OF AN ELONGATED LAMINA FOR RAYLEIOH'S DISC In this note Prof. Joukowsky deduces a simple formula f o r the moment of hydrodynamic pressure of a standing soundw a v e on a plate of which the normal cross-section is an ellipse. The velocity potential is expressed as the product ~ where A is a periodic function of time, and / is a function o f coordinates, determining a flow of the kind considered i n t h e article „On Suction Exerted on a Lamina by a Flow of Air", o n l y it is assumed that the velocity circulation 2/c around the l a m i n a is equal to zero. The moment of hydrodynamic pressure i s g i v e n by formula (13), which shows that the hydrodynamic forcest e n d to place the major axis of the plate at right angles t o t h e direction of the sound wave, and that the moment depends On the distance between the foci, and on the angle be tween t h e direction of the axes and that of the sound wave, and d o e s n o t depend on the dimensions of the plate.