Simultaneous scaler/velocity field measurements in turbulent gas-phase flows

In studying both nonreacting flows and flames it is useful to combine various imaging techniques to gain information that is not available from either instantaneous or time-averaged point measurements. The present work demonstrates a technique for combining particle-image velocimetry with planar laser-induced fluorescence in both a seeded air jet and a premixed flame. The results, which provide instantaneous images of both scalar and velocity fields, can be used to measure velocity distributions relative to contours in the scalar image. Of particular interest in the flame experiments is the ability to observe variations in the velocity field relative to contours of fuel concentration. In addition, the location of measured velocity vectors can be identified as being in either reactant or product regions of the flame. This capability permits the measurement of the mean and the fluctuations of both the product and reactant velocity fields.