Much has been said and written about the abilities of modern instrumentation to help solve problems of combustion in engines. In the main, however, the design and fabr ication of combustion chambers continues to be based on extrapolation of exper ience gained from use and rig tests, with little input from advanced techniques such as those based on optical diagnotics. At the same time, it has become increasingly difficult to design better combustion chambers without knowledge of the relevant flow processes. Thus, the future must involve improved understanding which, in turn, will require...