The water tunnel (Figure 5) provides colorful flow visualizations of fundamental flow structures such as vortices, and separations. Dye injections allow colors to be used to distinguish particular structures. One example is the vortex street shown in Figure 6. The water tunnel flow visualizations are used for qualitative analysis and computational flow dynamics (CFD) comparisons.
Recent work has included Particle Image Velocimetry (PIV) investigations of 2-D and 3-D flow control, such as the Flow Visualization and PIV Measurements of an Open Loop Forced Axisymmetric Bluff Body Wake. Using the Water Tunnel, experiments can be conducted to understand basic axisymmetric bluff body flow physics. Ability to capture high-quality still images documenting flow behavior of a forced wake. In addition, the collected data can be used to determine the “lock-in” region for specified forcing frequencies and methods for forcing and controlling the wake for feedback flow control systems.