As you may have guessed, this one is pretty nerdy. Confession: I am not a real aerodynamicist. I’m a mechanical engineer who specializes in fluid dynamics. Aerospace Engineering also concerns itself with fluid dynamics, mostly with the brach we call aerodynamics. Until my interest in baseball aerodynamics, I had never Continue Reading
General
Things that don’t neatly fit into the other topics
Magnus and Seam Shifted Wake Effects on Wilson 1030 and MLB baseballs: Post 64
My 14-year-old son plays baseball, and his fastball is about 90% efficient. So naturally, I was wondering if the baseballs that they use, which have very large seams compared to an MLB ball, move similarly to MLB balls. In my previous post, a Wilson 1030 baseball was found to move Continue Reading
Loopers, FA, CH, CU in the lab: Post 63
Here is an overlay of all the pitches I will be talking about in this post. Many thanks to Michael Augustine for making this beautiful overlay on short notice. Pitches 1-7, described below I am teaching a graduate measurements course this semester and the course requires a final project. I’ve Continue Reading
Not All Shifted Wakes Are Equal: Post 61
Twitter: @jwillyg20 It’s time to define a Seam Shifted Wake (SSW) pitch more carefully. The main feature is that a baseball’s seams can cause earlier flow separation on one side of the ball relative to the other. This asymmetric wake is what we refer to as the “shifted” wake (see Continue Reading
The Apparent Tilt of Seam Shifted Wake Pitches: Post 59
Conventional pitches break because of two forces, gravity and Magnus force (the ball experiences drag also, but drag his little effect on the direction of a pitch). When a Seam Shifted Wake (SSW) occurs, the forces causing break are gravity, Magnus force and the SSW force. This article will assume Continue Reading
Diagnosing and Modeling SSW pitches: Post 58
I’ve carried on about this, but if you throw a Seam Shifted Wake pitch, there is currently no way to know that it moved differently than any other pitch. I’ve known for some time that this was an obstacle to our work. I’ve been told many times that these effects Continue Reading
How to tell if you threw a SSW pitch, sinker/changeup edition: Post 57
This is a sinker/changeup edition because it is focused on vertical movement. I may tackle horizontal movement later. Say you are an ambitious pitcher looking to get ahead and have drank our Seam Shifted Wake Koolaid (it’s good!) Did the pitch work? How can you know? Note that, on their Continue Reading
UMBA 2.0
Click here for the GitHub link This new version contains a model for the seam shifted wake. Before I get into it I want to make a couple of things clear. First, there is a quote from statistician George E.P. Box, “All models are wrong but some are useful.” I Continue Reading
Killing Laminar Flow: Post 56
When you hear people describe flow over baseballs, there is frequent reference to the seams causing Laminar flow to become Turbulent. To start, I’d better explain what those terms mean. Laminar flow is what Juniors in Physics or Engineering learn about in their fluid dynamics class. It is usually steady Continue Reading
What Magnus Effect Looks Like: Post 53
My PhD Student, Nazmus Sakib, just published our first paper together, which was on Magnus Force and Reverse Magnus on golf balls. You can download it here if you are interested. While this site is about baseballs, Magnus is a lot easier to see on a golf ball since flow Continue Reading
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