Гидродинамика

SUMMARY 477 The above property of the vortex enables Prof. Joukowsky to solve the problem of silting of canals, assuming the water in the canal to be a seat of such elliptic vortices (Fig'. 8), able to sustain solid particles. Expressing the condition that the immer ­ sed solid particles near the bottonj are prevented by an elliptic vortex from falling on the bottom, Prof. Joukowsky obtains a linear relationship between the mean velocity of flow, v, and the channel depth, d where B, <7, b depend on the viscosity of water, on the roughness of the bottom, and on the largest hydraulic dimension of sus­ pended particles. This formula differs from that which was obtained by Kennedy (39) as a result of observations upon irri­ gation channels in India. To show the agreement between theory and observations, in Fig. 8 is given a comparison of the graph of Kennedy's curve with that of the relationship obtained by Prof. Joukowsky.