Seam-shifted wake

Last updated

Seam-shifted wake (SSW) is an aerodynamic phenomenon involving baseballs. The term was coined in 2019 by Andrew Smith during his work on the phenomenon with Barton L. Smith (no relation) at Utah State University (USU). Nazmus Sakib and John Garrett also contributed to the early work.

The USU group showed that Major League Baseball (MLB) baseball seams, when in specific locations relative to the direction of the ball, force the boundary layer to separate earlier (closer to the front of the ball) than it normally would. If this occurs on one side of the ball and not on the opposite side, a net force is produced. This force can be similar in magnitude to that caused by spin (i.e. the Magnus effect). [1]

In the particle image velocimetry image shown, the seam on the top of the ball is causing separation (wake formation) on the top closer to the front of the ball than normal. The separation on the bottom of the ball is at the normal location.

Particle Image Velocimetry image of a baseball at 90 mph SSWimage90mph.jpg
Particle Image Velocimetry image of a baseball at 90 mph

The resultant movement from this effect had been noted by others before [2] and named the "laminar effect" based on a mistaken notion that smooth portions of the ball caused a laminar boundary layer more prone to separation than a turbulent boundary layer. This was most often discussed with respect to 2-seam fastballs.

Data from MLB on pitch spin and movement, which were not available in 2019, now make it clear that SSW effects are present in most pitches. [3] Seam effects cause two-seam fastballs and changeups to develop addition arm-side movement as well as sink. Four-seam fastballs can gain extra vertical ride as well as glove-side movement. Certain sliders will "sweep" (or move arm-side) due to seam effects. [4] [5] [6] Some claim benefits from SSW pitches in terms of batter outcomes [7]

Evidence of seam-shifted wake pitches for MLB pitchers can be found by comparing spin-based movement to observed movement on MLB's Spin Leaderboard. [8] These two values being equal indicates no seam-shifted wake, while differences between them (called deviation) are a sign of seam-shifted wake. [3]

Several extensive explanations of how SSW works and what it does to pitches are available. [9] [10]

Related Research Articles

<span class="mw-page-title-main">Magnus effect</span> Deflection in the path of a spinning object moving through a fluid

The Magnus effect is an observable phenomenon commonly associated with a spinning object moving through a fluid. A lift force acts on the spinning object. The path of the object may be deflected in a manner not present when the object is not spinning. The deflection can be explained by the difference in pressure of the fluid on opposite sides of the spinning object. The strength of the Magnus effect is dependent on the speed of rotation of the object.

<span class="mw-page-title-main">Fastball</span> Baseball pitch thrown at a pitchers top speed

The fastball is the most common type of pitch thrown by pitchers in baseball and softball. "Power pitchers," such as former American major leaguers Nolan Ryan and Roger Clemens, rely on speed to prevent the ball from being hit and have thrown fastballs at speeds of 95–105 miles per hour (153–169 km/h) (officially) and up to 108.1 miles per hour (174.0 km/h) (unofficially). Pitchers who throw more slowly can put movement on the ball, or throw it on the outside of home plate where batters can't easily reach it.

<span class="mw-page-title-main">Slider (pitch)</span> Baseball pitch

In baseball, a slider is a breaking ball pitch that tails laterally and down through the batter's hitting zone. It is thrown at a speed that is lower than a fastball, but higher than the pitcher's curveball.

<span class="mw-page-title-main">Curveball</span> Type of pitch in baseball

In baseball and softball, the curveball is a type of pitch thrown with a characteristic grip and hand movement that imparts forward spin to the ball, causing it to dive as it approaches the plate. Varieties of curveball include the 12–6 curveball, power curveball, and the knuckle curve. Its close relatives are the slider and the slurve. The "curve" of the ball varies from pitcher to pitcher.

<span class="mw-page-title-main">Changeup</span> Baseball and softball pitch

A changeup is a type of pitch in baseball and fastpitch softball.

<span class="mw-page-title-main">Starting pitcher</span> Baseball or softball pitcher who throws the first pitch for their team in a game

In baseball, a starting pitcher or starter is the first pitcher in the game for each team. A pitcher is credited with a game started if they throw the first pitch to the opponent's first batter of a game. Starting pitchers are expected to pitch for a significant portion of the game, although their ability to do this depends on many factors, including effectiveness, stamina, health, and strategy.

<span class="mw-page-title-main">Pitch (baseball)</span> The act of a pitcher throwing a baseball from a mound to home plate

In baseball, the pitch is the act of throwing the baseball toward home plate to start a play. The term comes from the Knickerbocker Rules. Originally, the ball had to be thrown underhand, much like "pitching in horseshoes". Overhand pitching was not allowed in baseball until 1884.

<span class="mw-page-title-main">Two-seam fastball</span> Baseball and Softball pitch

A two-seam fastball is a pitch in baseball and softball. It is a variant of the straight fastball. The pitch has the speed of a fastball and can also include late-breaking action caused by varying the pressure of the index and middle fingers on the ball.

<span class="mw-page-title-main">Four-seam fastball</span> Baseball pitch

A four-seam fastball, also called a rising fastball, a four-seamer, or a cross-seam fastball, is a pitch in baseball. It is a member of the fastball family of pitches and is usually the hardest ball thrown by a pitcher. It is called what it is because with every rotation of the ball as it is thrown, four seams come into view. A few pitchers at the major league level can sometimes reach a pitch speed of over 100 mph. It is often compared with the two-seam fastball.

<span class="mw-page-title-main">Breaking ball</span> Baseball pitch that does not travel straight

In baseball, a breaking ball is a pitch that does not travel straight as it approaches the batter; it will have sideways or downward motion on it, sometimes both. A breaking ball is not a specific pitch by that name, but is any pitch that "breaks", such as a curveball, slider, or screwball. A pitcher who primarily uses breaking ball pitches is often referred to as a junkballer.

<span class="mw-page-title-main">Circle changeup</span> Baseball pitch

In baseball, a circle changeup or circle change is a pitch thrown with a grip that includes a circle formation, hence the name circle changeup. The circle is formed by making a circle with the index finger, holding the thumb at the bottom of the ball parallel to the middle finger and holding the ball far out in the hand. The ball is thrown turning the palm out.

Fast bowling is one of two main approaches to bowling in the sport of cricket, the other being spin bowling. Practitioners of pace bowling are usually known as fast bowlers, quicks, or pacers. They can also be referred to as a seam bowler, a swing bowler or a fast bowler who can swing it to reflect the predominant characteristic of their deliveries. Strictly speaking, a pure swing bowler does not need to have a high degree of pace, though dedicated medium-pace swing bowlers are rarely seen at Test level in modern times.

<span class="mw-page-title-main">Cut fastball</span> Baseball pitch

In baseball, a cut fastball or cutter is a type of fastball that breaks toward the pitcher's glove-hand side, as it reaches home plate. This pitch is somewhere between a slider and a four-seam fastball, as it is usually thrown faster than a slider but with more movement than a typical fastball. Some pitchers use a cutter to prevent hitters from expecting their regular fastballs. A common technique for throwing a cutter is to use a four-seam fastball grip with the baseball set slightly off center in the hand. A batter hitting a cutter pitch often achieves only soft contact and an easy out due to the pitch's movement keeping the ball away from the bat's sweet spot. The cutter is typically 2–5 mph slower than a pitcher's four-seam fastball. In 2010, the average pitch classified as a cutter by PITCHf/x thrown by a right-handed pitcher was 88.6 mph; the average two-seamer was 90.97 mph.

In baseball, an off-speed pitch is a pitch thrown at a slower speed than a fastball. Breaking balls and changeups are the two most common types of off-speed pitches. Very slow pitches which require the batter to provide most of the power on contact through bat speed are known as "junk" and include the knuckleball and the Eephus pitch, a sort of extreme changeup. The specific goals of off-speed pitches may vary, but in general they are used to disrupt the batter's timing, thereby lessening his chances of hitting the ball solidly or at all. Virtually all professional pitchers have at least one off-speed pitch in their repertoire. Despite the fact that most of these pitches break in some way, batters are sometimes able to anticipate them due to hints that the pitcher gives, such as changes in arm angle, arm speed, or placement of fingers.

<span class="mw-page-title-main">Gyroball</span> Type of baseball pitch popular among Japanese pitchers

A gyroball is a type of baseball pitch used primarily by players in Japan. It is thrown with a spiral-like spin, so that there is no Magnus force on the ball as it arrives at home plate. The gyroball is sometimes confused with the shuuto, another pitch used in Japan.

In baseball, a sinker or sinking fastball is a type of fastball which has significant downward and horizontal movement and is known for inducing ground balls. Pitchers capable of utilizing the sinker are able to throw the pitch almost exclusively, as it forces weak contact and ground balls, allowing them to rely less on secondary pitches in order to change speeds. While coaches agree that this pitch is very similar to the two-seam fastball, a two-seamer tends to have more lateral movement than a sinker. In either case, the pitch is thrown in a two-seam orientation and has a gyro angle far from 0 degrees, leading to Seam-shifted wake effects that cause downward and lateral movement compared to a four-seam fastball.

Boundary layer control refers to methods of controlling the behaviour of fluid flow boundary layers.

The shuuto (シュート) or shootball is a baseball pitch. It is commonly thrown by right-handed Japanese pitchers such as Hiroki Kuroda, Noboru Akiyama, Kenjiro Kawasaki, Daisuke Matsuzaka, Yu Darvish and Masumi Kuwata. The most renowned shuuto pitcher in history was Masaji Hiramatsu, whose famous pitch was dubbed the razorshuuto because it seemed to "cut the air" when thrown.

<span class="mw-page-title-main">Sidearm (baseball)</span>

In baseball, sidearm is a motion for throwing a ball along a low, approximately horizontal plane rather than a high, mostly vertical plane (overhand).

<span class="mw-page-title-main">Samuel Deduno</span> Dominican baseball player (born 1983)

Samuel Deduno Lake is a Dominican former professional baseball pitcher. He has played in Major League Baseball (MLB) for the Colorado Rockies, San Diego Padres, Minnesota Twins and Houston Astros.

References

  1. Smith, Andrew W; Smith, Barton L (March 2021). "Using baseball seams to alter a pitch direction: The seam shifted wake". Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology. 235 (1): 21–28. doi:10.1177/1754337120961609.
  2. "Laminar Express: Using Baseball Science to Enhance Two-Seam Fastballs". 21 January 2019.
  3. 1 2 Barton Smith, Alan M. Nathan and Harry Pavlidis "Not Just About Magnus Anymore". 5 November 2020.
  4. Eno Sarris "Is there a such a thing as a 'Dodgers Slider'?". 21 October 2021.
  5. Lindsey Adler "Why the Yankees pitching staff is embracing a new slider and how the 'whirly' is different from a traditional slider". 4 April 2022.
  6. Eno Sarris "Caught Looking: George Kirby's new slider, building Clarke Schmidt, and the origins of Stuff+ beer". 8 September 2022.
  7. Eno Sarris "What is 'seam-shifted wake' and which pitchers benefit most from it?". 21 January 2021.
  8. "Statcast Spin Axis All Pitches". baseballsavant. Retrieved June 22, 2023.
  9. Barton Smith. "Seam-Shifted Wake Cliff Notes". baseballaero. Retrieved July 14, 2023.
  10. "AN INTRODUCTION TO SEAM-SHIFTED WAKES AND THEIR EFFECT ON SINKERS". driveline. Retrieved July 14, 2023.