On Sunday, November 24, 2019 I will present to the American Physical Society Division of Fluid Dynamics on “The Baseball Seam: Clever and Capable Passive Flow Control” in Seattle. This is basically a spoken, 10 minute version of our video from Post 34. There is a lot more detail here. 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
The Seam Shifted Wake: Post 34
This is our video entry for the American Physical Society Gallery of Fluid Motion for 2019. As always, If you are new to our measurements, you may take a minute to read here about vorticity (the colors in our plots), boundary layer separation.
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
Live! (recorded) 3D Explanation of Laminar Express: Post 33
[If you are new to our measurements, you may take a minute to read here about boundary layer separation and wakes] A reader asked some very good questions about my claims, and I’ve attempted to answer these using a ball with a rod shoved through it. Comments, criticisms are welcome. 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
Kelvin-Helmholtz Instabilities and Baseballs, Jets, the Atmosphere, and Jupiter: Post 31
[If you are new to our measurements, you may take a minute to read here about vorticity (the colors in our plots), boundary layer separation] Anyone who studies fluid dynamics (flow of liquids AND gasses) probably has a fetish for vortices, or little whirls of fluid. Walk into any Fluid Continue Reading
Prediction of Flow Pattern of Laminar Express Over a Full Rotation: Post 30
[If you are new to our measurements, you may take a minute to read here about vorticity (the colors in our plots), boundary layer separation and wakes] We have recently tested some non-spinning MLB balls in orientations that are important to the “Laminar Express” pitch, which is a 2-seam fastball Continue Reading
My Latest Thoughts on Laminar Express: Post 29
I’ve written several times about this pitch, and each of those posts reflected an evolution of my thinking on it based on recent results. Our results continue to get better, and my thinking gets more definitive. So I thought I’d write an update. [If you are new to our measurements, Continue Reading
Primer on Understanding Our Results: Post 28
Starting in June, 2019, we use 2019 MLB balls in our testing unless otherwise stated. We measure the airflow over a moving ball using a measurement technique called Particle Image Velocimetry (PIV). The data we get back is the air velocity and direction everywhere in our image. In the picture Continue Reading