Synopsis
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1875 Excerpt: ... in rivers and open canals. The formula for this purpose is also derived from experiments, of which no less than ninety-one were made by Eytelwein on rivers and canals. The dimensions used by him are reduced to feet, and are the following:--c = wet contour, » = area of a section of the fluid,-= hydraulic mean depth, c g = force of gravity, a = angle of inclination of surface of stream, and v = mean velocity; then Note.--It has been proved that the greatest velocity is at the surface in the middle of the stream; from which it diminishes towards the bottom and sides, where the velocity is least. ON THE PERCUSSION AND RESISTANCE OF FLUIDS. 257. Prop.--When a stream impels a plane perpendicular to its action, the force with which it strikes the plane is as A d V; where A = area of the plane, d = density of the fluid, and V = its velocity. The impulsive force of the stream is as the number of particles that strike against the plane in a given time, multiplied by the force of each; and the number of particles that strike the plane in a given time is evidently = A d V; also, the force of each particle is proportional to V;.. the force of all the particles against the plane is as A d V2. Note.--It has been supposed that after the particles strike the plane, their action immediately ceases; but in reality they rebound, and acting on those which are behind, retard their velocity; therefore a difference will result between theory and experiment. 258. Cob.--If / = impulsive force of the stream against the plane A, k = a constant co-efficient to be determined by experiment, and h = height due to the velocity V, so that Vs = 2 g h; then f = 2A.kdgh. 259. Prop.--If a stream strikes perpendicularly on a plane which is itself in motion, the impulsive force is = A d (V-...
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