The overall objective of this continuing research program is to add to the basic understanding of time-dependent separated flow about bluff bodies. Using an existing U-shaped oscillating flow tunnel and extensive data acquisition system, accurate separation point data will be obtained through the use of smooth and rough cylinders immersed in a sinusoidally oscillating flow. Four methods will be used to determine the separation points as a function of time and flow mode: Differential Pressure Method, Surface Pressure Distribution Method, Flush Hot Film Surface Sensors, and the Dye Injection Method. The data will be compared with those predicted numerically during the course of the prior investigation through the use of the discrete vortex model. The proposed investigation will not only provide the much needed critical comparison but will also help to generalize the vortex methods by removing or reducing some of the assumptions. The interplay between the experimental data and the numerical analysis will enhance our fundamental understanding of time-dependent flow about bluff bodies at Reynolds numbers of practical concern.
