Particle Image Velocimetry (PIV) is our main measurement technique. It uses two laser sheet pulses to illuminate a slice of a flow. We add particles to the flow (theater fog, in our case), and the laser pulses illuminate these particles. Think of the lasers as a camera flash, but only Continue Reading
Our preliminary study using high-seamed Wilson 1030 baseballs and a brutal 3-wheel machine. These results were presented at the 2018 APS DFD meeting. These results are based on velocity measurements in the air using PIV. All of these data sets were acquired in a vertical plane. We start with a smooth Continue Reading
11/29/2020. I will leave the original post unchanged below, but some of our claims here proved to me untrue, or at least more nuanced than we realized. Were I to write this today, I’d point out that seams don’t matter most of the time when the ball has no gyro Continue Reading
The point here is that, when spinning on the same axis and no gyro, there is no difference between a 2-seam and 4-seam pitch.
In 2015, the number of home runs increased over 2014 by an amount larger than one would expect from year to year fluctuations. In 2016, MLB experienced a similar increase In 2017, the number of home runs increased again. Many fans believed that the increase was due to a deliberate Continue Reading
RPP tackled the same question (why 2 and 4-seam fastballs are different) back in July and came to the same conclusion (that seam orientation in itself does nothing) but from the opposite direction. They showed that a 4-seam pitch with side-spin induced at release would run the same way as Continue Reading