1 - Introduction

Abstract

This chapter deals with the discussion of fluid mechanics and open channel flows. The term hydraulics is related to the application of fluid mechanics' principles to water engineering structures, civil, and environmental engineering facilities. All real fluids resist any force tending to cause one layer to move over another, but this resistance is offered only while the movement is taking place. The resistance to the movement of one layer of fluid over an adjoining one is referred to as the viscosity of the fluid. In a static fluid, the pressure at one point in the fluid has a unique value, independent of the direction. An open channel is a waterway, canal or conduit in which a liquid flows with a free surface. An open channel flow describes the fluid motion in open channel. In most applications, the liquid is water and the air above the flow is usually at rest and at standard atmospheric pressure. Open channel flows are found in Nature as well as in man-made structures. In nature, rushing waters are encountered in mountain rivers, river rapids, and torrents. It is found that river flow rates range from extreme values and the hydraulics of droughts and floods are both important.