engineering

Swing bowling

Swing bowling is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Swing bowling rather than just read about it. In short: Swing bowling is a bowling technique in cricket, in which the ball is made to curve through the air, in the hope that the change in the ball's flight path will deceive the batter and cause them to play the ball incorrectly. A bowler who uses this technique is called a swing bowler.

Key takeaways

Swing bowling belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Swing bowling to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Swing bowling from memory before moving on to harder problems.

Reference excerpt

Swing bowling is a bowling technique in cricket, in which the ball is made to curve through the air, in the hope that the change in the ball's flight path will deceive the batter and cause them to play the ball incorrectly. A bowler who uses this technique is called a swing bowler. Swing bowling is generally classed as a type of fast bowling. A swing bowling delivery is either an inswinger, where the ball curves in towards the batter, or an outswinger, where the ball curves away from the batter. A swing bowler often bowls a mixture of inswingers and outswingers (as well as other non-swinging types of delivery), by changing how they hold the ball. To make the ball swing, a bowling side continually polishes one side of the ball by applying sweat to it, as well as rubbing it against their clothing to shine it, while allowing the opposite side to become gradually more rough through the course of play. Conventional swing, also called orthodox swing, occurs when the ball is relatively new, before the shiny side becomes worn over the course of play. The airflow over the rough and shiny sides cause it to move in flight towards the rough side and away from the shiny side. Swing bowlers often use a subtly altered grip on the ball to accentuate this effect. Reverse swing is when it swings in the opposite direction - towards the shiny side. This occurs as the ball becomes more worn, and is rarer. As swing bowling is heavily dependent on the condition of the ball, a number of ball tampering controversies have been related to it. This is where teams have allegedly tried to alter the wear of the ball illegally using materials such as sandpaper, to produce additional swing. Examples of such incidents are the 2006 ball-tampering controversy and the 2018 Australian ball-tampering scandal.

History

Theory The purpose of swing bowling is to get the cricket ball to deviate sideways as it moves through the air towards or away from the batter. To do this, the bowler makes use of six factors:

The raised seam of the cricket ball The angle of the seam to the direction of travel The wear and tear on the ball The polishing liquid used on the ball The speed of the delivery The bowler's action Asymmetry of the ball is encouraged by the polishing of one side of the ball by members of the fielding team, while allowing the opposite side to deteriorate through wear and tear. With time, this produces a difference in the aerodynamic properties of the two sides. Both turbulent and laminar airflow contribute to swing. Air in laminar flow separates from the surface of the ball earlier than air in turbulent flow, so that the separation point moves toward the front of the ball on the laminar side. On the turbulent flow side it remains attached longer, separating towards the rear and steering the wake to one side, generating a lift force.

Conventional swing

Typically, a swing bowler aligns the seam and the sides of the ball to reinforce the swing effect. This can be done in two ways:

Outswinger: An outswinger to a right-handed batter can be bowled by aligning the seam slightly to the left towards the slips and placing the roughened side of the ball on the left. To extract consistent swing, a bowler can also rotate their wrist toward the slips while keeping their arm straight. To a right-handed batter, this results in the ball moving away to the off side while in flight, usually outwards from their body. James Anderson, Malcolm Marshall, Bhuvneshwar Kumar, Richard Hadlee, Kapil Dev, Tim Southee, Mitchell Starc, Dominic Cork, Courtney Walsh and Dale Steyn have been great exponents of the outswingers. Inswinger: An inswinger to a right-handed batter can be bowled by aligning the seam slightly to the right and placing the roughened side of the ball on the right. To extract consistent swing, a bowler can also rotate or "open up" their wrist towards leg slip. To a right-handed batter, this results in the ball moving in to the leg side while in flight, usually inwards towards their body. The curvature of swing deliveries can make them difficult for a batter to hit with their bat. Typically, bowlers more commonly bowl outswingers, as they tend to move away from the batter, meaning they have to "chase" the ball to hit it. Hitting away from the batter's body is dangerous, as it leaves a gap between the bat and body through which the ball may travel to hit the wicket. Also, if the batter misjudges the amount of swing, they can hit the ball with an edge of the bat. An inside edge can ricochet on to the wicket, resulting in them being out bowled, while an outside edge can fly to the wicket-keeper or slip fielders for a catch. There has been a distinct lack of left-arm swing bowlers in the game. Some of the most famous left-arm bowlers were Pakistan's Wasim Akram, Mohammad Amir and Shaheen Afridi, India's Zaheer Khan and Irfan Pathan, Australia's Alan Davidson, Mitchell Johnson and Mitchell Starc, Sri Lanka's Chaminda Vaas and New Zealand's Trent Boult. When the ball is new the seam is angled to one side, back-spinning the ball with the fingers for stability in flight. This causes the boundary layer on the side of the seam to become turbulent and separate later than the laminar flow on the other side, making the ball swerve.

Reverse swing

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Swing bowling

Start with the simplest possible case. Write down what Swing bowling claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Swing bowling before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Swing bowling ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Swing bowling

In research: Swing bowling appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Swing bowling in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Swing bowling is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aerodynamics, Bowling (cricket), Cricket terminology, so understanding it makes those chapters shorter.
In everyday life: Look for Swing bowling outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Swing bowling in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Swing bowling means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Swing bowling out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Swing bowling in simple terms?

Why does Swing bowling matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Swing bowling?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Swing bowling.