General

[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

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

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

I was recently contacted by Dr. James A Scobie, a Lecturer at the University of Bath in England. He straightened me out on a few points about Cricket from my previous post. Specifically, he says: In cricket the bowler isn’t allowed to deliberately alter the ball. It’s true that the Continue Reading

This may sound cranky. I love hearing ideas from others, but some I am rather dismissive of, and I want to explain why. Cricket balls Let’s talk about the 40 ways cricket balls are nothing like baseballs. The leather of a cricket ball is covered in shellac which is easily Continue Reading

Some of these may not mean a lot to lay persons. I’m putting this here so I can keep my eye on the ball and in case anyone like-minded wanders by. As these questions are answered, I’ll change them to italics and link the answer to the Yes or No. Continue Reading

Here’s a very nice description of transition from laminar to turbulent flow and how that is distinct from yet often correlated to boundary layer separation. This may help you better understand my description of how seams and pressure gradients interact as well as how that may lead to the Laminar Continue Reading

OK, this is some hardcore fluid dynamics. Hang on tight. But understanding this concept is key to understanding how seams may effect laminar/turbulent flow and boundary layer separation. As a baseball moves through the air, the pressure on the front of the ball is higher than the surrounding air, which Continue Reading

A boundary layer exists whenever a fluid (liquid or gas) flows over a surface.  The boundary layer is the part of the gas that feels the skin of the baseball and is thus accelerated. The concept of the boundary layer was introduced by Ludwig Prandl in 1904.  He is commonly Continue Reading

The “Knuckleball is thrown off the tips of the fingernails in a manner that inhibits spin (or at least when thrown with great skill). As shown in our post on 2-seamers and on one on the seam’s affect on boundary layer, the location of boundary layer separation tends toward the Continue Reading