Photon-Correlation Laser Velocimetry in Reciprocating-Engine Research

Abstract

Following a detailed review of practical aspects of photon-correlation laser-Doppler velocimetry, automotive applications are surveyed with emphasis on broad experimental and interpretive concerns common to unsteady flows and confined environments. Such situations typically permit only limited optical access and thereby place a premium on efficient operation with weak (single-photon) signals in the presence of considerable noise. Fast, robust data-acquisition and -reduction techniques that minimize user intervention are described. The survey of automotive applications concentrates on turbulent in-cylinder flow fields and combustion, but briefly includes wind-tunnel and soot-sizing measurements.