91Ó°ÊÓ

A pipe carrying water tapers from a cross-section of \(0.3 \mathrm{~m}^{2}\) at \(A\) to \(0.15 \mathrm{~m}^{2}\) at \(B\) which is \(6 \mathrm{~m}\) above the level of \(A .\) At \(A\) the velocity, assumed uniform, is \(1.8 \mathrm{~m} \cdot \mathrm{s}^{-1}\) and the pressure \(117 \mathrm{kPa}\) gauge. If frictional effects are negligible, determine the pressure at \(B\).

Oil of relative density \(0.85\) issues from a \(50 \mathrm{~mm}\) diameter orifice under a pressure of \(100 \mathrm{kPa}\) (gauge). The diameter of the vena contracta is \(39.5 \mathrm{~mm}\) and the discharge is \(18 \mathrm{~L} \cdot \mathrm{s}^{-1}\). What is the coefficient of velocity?

Oil of relative density \(0.85\) issues from a \(50 \mathrm{~mm}\) diameter orifice under a pressure of \(100 \mathrm{kPa}\) (gauge). The diameter of the vena contracta is \(39.5 \mathrm{~mm}\) and the discharge is \(18 \mathrm{~L} \cdot \mathrm{s}^{-1}\). What is the coefficient of velocity?

A vertical venturi-meter carries a liquid of relative density \(0.8\) and has inlet and throat diameters of \(150 \mathrm{~mm}\) and \(75 \mathrm{~mm}\) respectively. The pressure connection at the throat is \(150 \mathrm{~mm}\) above that at the inlet. If the actual rate of flow is \(40 \mathrm{~L} \cdot \mathrm{s}^{-1}\) and the coefficient of discharge is \(0.96\), calculate (a) the pressure difference between inlet and throat, and \((b)\) the difference of levels in a vertical U-tube mercury manometer connected between these points, the tubes above the mercury being full of the liquid. (Relative density of mercury = 13.56.)