Experimental Investigation of a Coflowing Round Jet
Abstract
We will report on coherent vortical motions present within the flow field of a round coflowing jet. The experiments demonstrate how these motions relate to the mean jet behavior and how they compare to observed topological features. The experiments are performed in water with various jet and coflow velocities at Reynolds numbers (based on jet velocity) up to 10000 and locations ranging from the jet exit to 100 diameters downstream. The time-dependent and mean behavior of the coflowing jet are compared using the results of experimental techniques which include digital particle image velocimetry (DPIV), laser doppler velocimetry (LDV) and laser induced fluorescence (LIF). Our earlier results have demonstrated a difference between the convective behavior of the topological structures observed with LIF and the vortical motions resolved through the use of DPIV such that the measured convection speeds were not in agreement. The reasons for this difference are presented in more detail, and the relationship between the mean jet behavior and the coherent features is discussed within the context of the LDV measurements.
- Publication:
-
APS Division of Fluid Dynamics Meeting Abstracts
- Pub Date:
- November 1999
- Bibcode:
- 1999APS..DFD..KC01J