<p>Frisbees are a popular activity for entertainment and professional sport. The aerodynamics study of the frisbee is crucial to understand its movement and the optimal design of next-generation frisbee. In this project, focusing on the aerodynamic characteristics and flying performance, we used computational fluid dynamics to understand the physics involved in throwing a frisbee and then investigate the parameters that affect the trajectory, the maximum distance/height, and the optimal design of a frisbee. First, we analyzed the aerodynamic forces on a moving frisbee, including lift force, drag force, and gravity. To be specific, we used Bernoulli's equation to evaluate lift force and Prandtl's relationship to represent the drag force working on a flying frisbee. Second, we derived a set of governing equations, which describe the movement of a frisbee. Then, by using Euler's method as a numerical approach, we presented discretized presentations of the governing equations. Third, we developed a computer program (with Matlab) to evaluate the trajectory, the maximum distance/height of a frisbee. With the developed computer program, we investigated how the parameters, such as attack angle, initial speed, frisbee diameter, ambient wind speed, variations influence the aerodynamic characteristics and a frisbee's flying performance, particularly maximum distance. For the consideration of attack angle, we found that maximum distance increases with the increase of the attack angle in some range and decreases with the increase of the attack angle in another range, and it reached the maximum value when the attack angle is near 12.5°. Meanwhile, the maximum height behaved monotonically, which always increases with the increase of the attack angle. For the consideration of initial speed, we found that the increase of initial speed always makes a larger maximum distance and a higher maximum height. For the consideration of frisbee diameter, it is found that with the increase of frisbee diameter, the flying range (maximum distance) increase and then decrease, and the peak flying range appears when the value of the frisbee diameter is around 0.34m. It is noted that the relationship between the frisbee diameter and the flying range can be used for the optimal design. In addition, we investigated the effects from the ambient environments, such as horizontal and vertical wind speed. It is found that the horizontal wind speed always increases the flying range when it is aligned with the moving direction and decreases the flying range when it is in the opposite direction. Finally, we designed the user graphic interface and published the software for public use. By inputting the basic settings of the frisbee, such as frisbee diameter, initial velocity, attack angle, wind speed, etc., any user, without knowing the aerodynamic theories, can use this software to quickly determine the trajectory and maximum distance with ease.</p>

A Prediction Software to Evaluate Frisbee Movement

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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