Mixing in crossflowing jets: Turbulence quantities

Simultaneous planar laser-induced fluorescence (PLIF) and particle image velocimetry (PIV) yield measurements of two-dimensional jet fluid concentration and velocity fields, both the mean and fluctuating terms, in turbulent crossflowing jets. The jet-to-crossflow velocity ratio is r = 5.7 and the jet exit Reynolds number is approximately 5000. The measurements concern the developing region of the flow. Two flow configurations are studied, one in which the jet nozzle is flush with the tunnel wall and the other where the nozzle protrudes into the uniform region of the tunnel flow. The jet nozzle in both cases is a simple pipe. Previous work focused on the averaged scalar and velocity fields. Here, we discuss the resolution issues bearing on the determination of small scale fluctuations, and present results for the averaged scalar variance, 〈C2〉, the scalar flux components, 〈uiC〉, the turbulent normal stresses, 〈u′2〉 and 〈v′2〉, and the turbulent shear stress, 〈u′v′〉. These results should prove particularly useful for assessment of crossflowing jet simulation efforts. The range of length scales spanned by the measurements also makes possible direct assessment of models and model assumptions used for scalar transport and mixing in largeeddy simulation (LES). Sample results demonstrate the use of the present data in these LES model assessments.