Planar velocity measurements in incompressible mixing layers

Michael G. Olsen, J. Craig Dutton

Research output: Contribution to conferencePaperpeer-review


Instantaneous, planar velocity measurements have been made for an incompressible mixing layer using a facility that was designed and built specifically for particle image velocimetry (PIV) experiments. The mixing layer has layer high-speed freestream velocity of 40 m/s and a low-speed freestream velocity of 23 m/s, corresponding to a velocity ratio of r = 0.575. The mixing layer was first characterized using hot-film anemometry by measuring mean and fluctuating velocities and power spectra. An ensemble of 15 PIV photographs was then obtained at a location 150 mm downstream of the tip of the splitter plate, where the mixing layer is fully-developed. The spatial resolution of the velocity vector fields is 0.4 mm, and the fields consist of 100 vectors in the streamwise direction and 135 vectors in the transverse direction. Velocity and vorticity fields are presented, as well as enlargements of flow features of interest. The velocity fields provide intricate detail about large-scale structures in the mixing layer. The pairing of large-scale Brown-Roshko structures is seen, and in both velocity vector and vorticity plots, it appears that the interacting roller structures retain some of their individuality after the pairing is seemingly completed. In addition, the three-dimensionality of the mixing layer is clearly seen, with sink-like structures observed at the centers of some of the large-scale structures. Finally, details of the shape and orientation of the roller structures is observed. While most of the structures are roughly circular in shape, some are elliptical with relatively large eccentricity.

Original languageEnglish (US)
StatePublished - 1998
EventProceedings of the 1998 ASME Fluids Engineering Division Summer Meeting - Washington, DC, USA
Duration: Jun 21 1998Jun 25 1998


OtherProceedings of the 1998 ASME Fluids Engineering Division Summer Meeting
CityWashington, DC, USA

ASJC Scopus subject areas

  • General Engineering


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