Comparing Strouhal Numbers

This is a video showing the comparison of different Strouhal numbers, which are functions of the varying sweep angles, 5, 10, 15, 20, 30, 40, 50, 60, and 70 degrees. Each trial shown also occurs at the same Reynolds number equal to 546.9. The Reynolds number is a function of the 6.0 Hertz channel flow setting that controls the velocity at which the water is flowing. The video compares the vortices that occur in the flow behind the test piece at the 40% half-span planar location. It is good to see that the trials with Strouhal numbers between 0.2 and 0.4 display well formed vortex structures, considering that other researches have observed fish to swim at Strouhal numbers within that range. The test piece being used is the “1common“ dolphin caudal fin shape.