Future Experiments

     The previous experiments have allowed the exploration of various configurations regarding the structure’s shape as well as varying fin geometries. These experiments were conducted with a constant Reynolds number of approximately 80,000. With the data received from these experiments, the scope of future experiments will be expanded to include more fin shapes for more precise data collection at different flow rates. The next experiment will be conducted similarly to the last, by analyzing the frequency of the fin’s oscillations for the new configurations. These configurations will maintain both cylindrical and square tube structures, as well as similar fin lengths, with the addition of 3.5” and 4” fins to the total. There will also be a tapered design for the fin that will resemble the wing of an aircraft which will be subjected to a similar frequency analysis as the “different model geometries over constant flow rate” experiment. In the previous experiment, a cylindrical bluff body was attached to each fin length to analyze the variance of the frequency compared to the same length without said attachment. In the next experiment, the shape of the attachment will be changed to include a planar surface that affixes normally to the fin in order to observe the interaction between this new configuration and the vortices produced by the cylinder and square structures.

     Varying the Reynolds numbers in the new experiments will  allow for a more complete analysis of the structure’s construction since there will be a better understanding of whether the higher flow rates create a higher frequency or if the geometry of the model is the primary contributor to the maximization of the oscillating frequency. Varying the Reynolds number will alter the formation length of the vortices as they are produced behind the bluff body structure. This will ultimately affect the efficiency of the oscillating fin and will allow for the design of an optimum shape based on a range of realistic Reynolds numbers.

     Further experiments will involve video analysis of the movement of the fin while capturing the vortex masses, allowing for not only a more precise calculation of the frequency of the movement but also the amplitude of the oscillations, which will have a significant impact on the total power captured and converted from the vortices. The video analysis experiment to determine amplitude will be performed by completion of the following procedure:

1. Affixing a camera at a known height directly above the oscillating fin
2. Create and place a reference grid between the camera lens and the fin that will allow the tracking of the position of a point marked on the fin
3. Use video analysis software to record the displacement of the point on the fin over time, thus establishing the amplitude of the oscillations.
4. Use the video analysis software to track the frequency of the fin’s movement by using video frame analysis

Future analysis of the frequency of the oscillating fin will be performed by use of the video analysis software described above to provide more precise frequency data. These experiments will allow for the optimization of the design parameters for the most efficient conversion of the mechanical energy of the device into electrical power by operation of a motor. The mechanical-to-electrical power conversion will be a pivotal component of future experiments to determine the optimal mechanism design to most efficiently convert the mechanical energy of the oscillating fin into electrical energy output by the motor.

1. Extended hinge pin – transfers the rotating motion of the oscillating fin vertically out of the flow of the water
2. Slider and track assembly – converts arc-motion of the fin into straight-line motion by channeling the motion of the extended hinge pin through the track
3. Connecting Rod – Connects slider straight-line motion to a circular disk in such a way as to allow rotation of the disk
4. Rotating Disk with Motor Drive Shaft – Completes the oscillating motion conversion into strictly rotational motion, thus rotating the motor drive shaft and producing electrical current by means of a standard motor design
5. electrical current by means of a standard motor design (Part D)