Flow in Conduits

Publisher Summary This chapter provides an overview on hydraulics. The analysis of water flow in closed and open conduits depends on three fundamental principles such as the conservation of mass, energy, and momentum. Each principle is considered in terms of the equation(s) derived from its application. The first well-known formula for flow in pipes is proposed by deChezy. Another formula, the Hazen–Williams (H–W) formula, is widely used in the United States. The most common equation used in the United States for open channel flow is the Manning equation. The most universal (and one of the quickest) means for solving open channel flow with or without the Escritt modification are found in a user-friendly program, UnifCrit2.2 developed by Cahoon. UnifCrit2.2 solves the Manning equation either unmodified (Escritt=0 in the program) or modified by the use of R m (Escritt=1) in round pipes. This versatile program also solves for critical velocity, depth, and flow in both round and trapezoidal conduits. Computational fluid dynamics is a powerful method for predicting fluid motion in a continuum by using numerical techniques. The Navier–Stokes equations governing fluid motion are valid at all points but, as it is not feasible to calculate flow characteristics at every point, the equations are solved at a finite number of points called “nodes.”