This book is an exposition of the derivation and use of equations of motion for multiphase flow. This includes bubbly liquids and particle-fluid mixtures.

The approach taken is to derive the equations of balance using ensemble averaging. They are the same as those derived from control volume methods. Closure for dispersed flows is discussed, and some fundamental solutions are given.

The work focuses on the fundamental aspects of two-phase flow, and is intended to give the reader a background for understanding the dynamics as well as a system of equations that can be used in predictions of the behavior of dispersed two-phase flows.

The exposition in terms of ensemble averaging is new, and combining it with the concepts of modern continuum mechanics makes this book unique.

The book is intended for engineering, mathematics and physics researchers and advanced graduate students working in the field.