Hydraulics of Pipe Lines (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 edition. Excerpt: ...Coefficient efflux /=-96, and hence l/2gf =-016177. Velocity S = 4000 (fs). Note should also be made that in the formulae relating to closure (equation (52), etc.) h positive implies excess of pressure, while in the formulae relating to opening (equation (76), etc.) h positive implies defect of pressure or depression. Also in all diagrams relating to closure, h positive is laid off upward while in those relating to opening, h positive is laid off downward. On certain diagrams, the heavy dot calls attention to the point where i-z and the circle to the point of arrest of valve movement. Full lines refer to pressure head h. Dotted lines refer to velocity v. Via. 49.--History Of Pressure Head h And Velocity V (closure) From this point on the course will depend on the time T in relation to z and on the hydraulic characteristics of the case. The more typical cases are as follows: (a) The curve may continue on reproducing very nearly the form of Fig. 48a, but reaching a value of h somewhat lower at the point of complete closure. Fig. 496 represents a case of this type. (6) The curve may continue on rising gradually, but with a more decided break at the point where t=z and reaching a maximum value at complete closure considerably less than in the case where 27z. Scale of m/mc Fio. 50.--History Of Pressure Head h (closure). L H m0 ml z T 20,000 850-05 0 10 2z Dotted line shows continuation for Case T=z Figs. 49c, 50 represent cases of this type. (c) The curve may continue nearly horizontal, or with a nearly constant value of h, until the closure is complete. In some cases there may be a slight gradual rise, or again a gentle rise to a maximum followed by a slight decline, or again an immediate sharp decline. Figs. 516, c, 526 represent cases of...