The State of the Baseball Aerodynamics is Strong! Sorry, always have wanted to do that. I’ve been at this for about 14 months. I thought this would be a good time to provide a (hopefully) concise summary of what we have learned. Seam Effects on Pitch Break I nearly said Continue Reading
Drag
2019 in Review: Post 40
With 2020 around the corner, I thought I’d step back and look at what we have learned. Just about a year ago, I wrote the questions shown below in italics. Below each question, I will describe my current understanding of that topic. What effects baseball drag? Seam height Center of Continue Reading
The Non-Centered Pill Baseball Drag Theory: Post 36
Here is an excerpt from the MLB Home Run Committee report from 2017. The committee has not yet succeeded in definitively explaining the cause of the decreased drag coefficient beginning in 2015. Various hypotheses have been proposed and tested, including gradual changes in the manufacturing process affecting the centering of Continue Reading
Effect of Seam Height on Wake of MLB Baseballs: Post 35
The huge home run rate in 2019 has led to a lot of questions from players and fans. According to the report published in 2017 by the MLB Home Run Committee (which you should read), the drag of baseballs decreased some from 2015 – 2016 – 2017 and the home Continue Reading
Seam Height ball-to-ball/year-to-year Variation: Post 32
Mike Fast of the Atlanta Braves generously gave us a whole crate of 2019 balls, 6 dozen total. I asked John measure each one on and off the seams in several places and record the average difference as the seam height. It’s a crude measurement compared to the laser scans Continue Reading
Saberseminar 2019 Presentation “What do Baseball Seams do to a Ball in Flight?”: Post 27
Ball Smoothness, Roundness and Drag: Post 26
I’ve just been listening to Jonah Keri’s great interview with Dr. Meredith Wills on an Athletic podcast. They were discussing her recent Athletic article about the 2019 balls as well as her two early articles. This recent article has made a huge splash and I am happy that Dr. Wills Continue Reading
Baseball Rubbing Mud and its Effect on Roughness: Post #25
As we showed in post 23, a ball with rough leather tends to produce a turbulent flow which delays the boundary layer separation. Roughness, in fluid dynamics, is difficult to nail down. We typically use “relative roughness” which is a ratio of the mean height of the roughness to (in Continue Reading
Seam height, drag, and carry: Post #24
You may have heard that there have been a lot of home runs in the MLB in 2019. I’d link some articles, but there are so many that I’ll just recommend Google. There is also evidence that the seams on the balls currently being used in MLB are smaller than Continue Reading
Baseball Roughness Effect on Laminar Separation: Post #23
Until recently, we used a Hack Attack 3-wheeled pitching machine to launch baseballs. If you’ve ever used one of these, you know they are brutal on the baseballs. Also, the balls we used were Wilson 1010 or 1030 high-seamed balls. I’ve been careful to point out that those results may Continue Reading