Structure and Properties of Water

Abstract

Abstract Water moves in response to forces acting on it, and its physical properties determine the qualitative and quantitative relations between those forces and the resulting motion. Thus, it is important for the student of hydraulics to have an understanding of these properties. This chapter begins with a description of the atomic and molecular structure of water that give rise to its unique properties, including the fact that it occurs in the gaseous, liquid, and solid phases at the earth’s surface. The nature of water in its three phases and the phenomena that accompany phase transitions in nature are briefly described. The last portion of the chapter uses a series of thought experiments to elucidate the properties of liquid water that are crucial to understanding its behavior in open-channel flows. This section emphasizes the dimensional nature of the various properties, and you may want to refresh your understanding of physical dimensions by reviewing appendix A.