Reactive flows encompass a very broad range of phenomena, including flames, detonations, chemical lasers, the earth's atmosphere, stars and supernovae, and perhaps even the elementary particle interactions in the very early stages of the universe. Despite the obvious physical differences among these flows, there is a striking similarity in the forms of the descriptive equations. Thus the considerations and procedures for constructing numerical models of these systems are also similar.

There has been an enormous growth in computational capabilities and resources since the first edition of this book appeared in 1987. What were difficult, expensive computations can now be done on desktop computers. Available hardware has improved almost beyond recognition. Supporting software is available for graphics and for handling large amounts of output data. New paradigms, such as parallel and massively parallel computing using distributed or shared memory, have been developed to the point where they are available to most users. Recipes also exist to interconnect desktop computers to build personal parallel computers.

With the explosive growth in available computer technology, there has been concomitant growth in the use of this technology to solve complex reactive-flow problems having numerous physical processes interacting simultaneously on many different time and space scales. The ability to solve these problems is underpinned by significant developments in numerical algorithms for solving the governing equations. With so many practitioners, many new avenues have been explored, and a number have been developed significantly.