Baseball Drag Measurements in Free Flight

Lloyd Smith,Andrea Sciacchitano

doi:10.3390/app12031416

Lloyd Smith, Andrea Sciacchitano

Open Access

https://doi.org/10.3390/app12031416

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Abstract

While baseball is a popular sport with a storied history, the aerodynamic properties of the seamed sports ball are not fully understood. Reported aerodynamic baseball behaviors are primarily based on force measurements from wind tunnels. The following describes a methodology to measure baseball drag in free flight from changes in its speed. The method relies on a high accuracy ball delivery device and speed measurement system. It avoids the large infrastructure, stinger attachment and blockage effects associated with wind tunnels. In the present work, we examined the baseball drag as a function of orientation and with spin. The drag values retrieved from the proposed method are in good agreement with radar and video measurements. However, they are lower than those reported in other wind tunnel measurements, which was attributed to differences in the balls that were tested or the stinger attachment.

Highlights

Major League Baseball (MLB) is the third most popular sport in the United States, with 20 million viewers during the 2017 World Series alone [1]
Drag from spinning balls agreed with wind tunnel and other free flight measures of drag
Ball drag was measured as a function of orientation, which generally agreed with similar measures from a wind tunnel

Summary

Introduction

Major League Baseball (MLB) is the third most popular sport in the United States, with 20 million viewers during the 2017 World Series alone [1]. The home run is an important aspect of the game and is often normalized as the number of home runs per batted ball (HR/BB). From 1960 to 2015, the HR/BB varied from 0.03 to 0.04, changing gradually from year to year with no apparent trend. The MLB commissioned a panel to study the unprecedented and dramatic change, which concluded that a small decrease in the ball’s aerodynamic drag (3%) was responsible for the increased offense [2]. The high sensitivity of HR/BB to ball drag has motivated increased scrutiny of baseball drag and the methods used to measure it

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Results

Conclusion