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
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
Laminar and Turbulent Boundary Layer Separation on New MLB balls Post #22
We are continuing our measurements on MLB balls and are learning some interesting things. First off, the physics are a bit more complicated than they were on machine-pitched high-seam balls. In that case, we found that the boundary layer was always turbulent when it separated. This finding made me somewhat Continue Reading
First PIV Measurements on MLB Balls Post #21
Thanks to Mike Fast of the Atlanta Braves and Professor Lloyd Smith at Washington State University, we have a large collection of brand new MLB balls and a means to launch them at high speed without damaging the ball. And we’ve rebuild our PIV setup. I am confident that this Continue Reading
Baseball Drag Crisis Post #20
Engineers and Physicists talk funny sometimes, and the term”drag crisis” is an example of funny talk. It’s not what you think. It does not refer to the huge increase in home runs in the MLB due to unexplained changes in the drag force on baseballs. It refers to a rather Continue Reading
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