Laser Anemometry for Engine Flow Studies

Interferometric laser anemometry was used to determine cycle-resolved velocity records within the cylinder of a laboratory engine. Direct recording of the signal enables two new types of information to be collected. For single seeds, two-dimensional projections of seed trajectory are measured to yield information about microscale turbulence. For multiple seeds, continuous records of velocity versus time are found to contain velocity fluctuations on a smaller time scale than previously measured in an engine. A discussion of the simple apparatus will be presented, along with some suggestions for noninterferometric flow measurement.