water waves - 2025 ACF Nationals

Tossup

An equation describing these phenomena was derived by Davis and Acrivos and uses the Hilbert transform to model instantaneous pressure. The use of Jacobi elliptics to solve a form of these phenomena leads to them being called cnoidal (10[1])(“cuh-NOY-dull”). By setting a parameter (10[1])describing these phenomena equal to infinity in the ILW equation, one recovers the Benjamin–Ono equation. Solving the differential equation [read slowly] “u triple (10[1])prime (10[2])minus (10[2])six (10[1])u u prime (10[2])minus c u prime equals zero” gives one of these phenomena (10[1])that is proportional (10[1])to (10[1])hyperbolic secant squared and that maintains its shape. These (0[1])phenomena are called collapsing if their (-5[1])Iribarren number is sufficiently large. The first observed soliton was one of these phenomena. (-5[2])These phenomena reach a critical point and then break, (-5[1])leading to eddies. (10[2])For 10 points, name these phenomena (-5[1])that include tsunamis. (10[2])■END■ (10[6]0[3])

ANSWER: water waves [accept any body of water so long as they say waves; accept solitons until read; accept surface waves or (surface) gravity waves or wind waves or breaking waves or deep water waves or intermediate water waves or shallow water waves; accept breakers until “break” is read; prompt on waves by asking “in what medium?”] (The first line is the Benjamin-Ono equation. The third line is the depth parameter. The differential equation is KdV.)

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Buzzes

Player	Team	Opponent	Position	Value
Adam Fine	Chicago A	Stanford	37	10
David Bass	Johns Hopkins	Minnesota	41	10
Geoffrey Wu	Columbia A	Indiana	62	10
Swapnil Garg	UC Berkeley A	North Carolina A	63	10
Richard Niu	Cornell A	Virginia Tech	63	10
Cade Reinberger	RIT	North Carolina B	64	10
Liam Kusalik	Waterloo A	Northwestern	64	10
Benjamin Chapman	Toronto A	Illinois A	65	10
Leo Law	Florida	British Columbia	68	10
Jeremy Cummings	WUSTL A	Rutgers	68	10
Colin Veevers	Ottawa	Georgia State	79	10
June Yin	WUSTL B	UC Berkeley B	82	10
Caleb Ott	Waterloo B	LSE	83	10
Nathan Sheffield	MIT	Toronto B	92	0
Raymond Chen	Toronto B	MIT	98	-5
Bryan Ugaz	Arizona State	NYU	112	-5
Simon Zimmerman	Ohio State	Michigan	112	-5
Conor Thompson	Iowa State	Chicago B	121	-5
Joseph Chambers	Virginia	Cornell B	124	10
Rohan Dalal	Georgia Tech	Toronto C	124	10
Yash Mandavia	Illinois B	Winona State	130	-5
Ezra Santos	Chicago B	Iowa State	133	10
William Orr	Yale	Penn State	133	10
Gavin Markoff	Vanderbilt	Columbia B	134	0
Olin Bose	Columbia B	Vanderbilt	134	10
Jacob Hardin-Bernhardt	NYU	Arizona State	134	0
Yashwanth Bajji	Michigan	Ohio State	134	10
Michael Kearney	Harvard	Texas	134	0
Athena Shadden	Texas	Harvard	134	10
Kunaal Chandrashekar	Toronto B	MIT	134	10
Thomas Tibbetts	UCF	Maryland	134	10
Henry Bon	Winona State	Illinois B	134	10

Summary

Tournament	Exact Match?	TUH	Conv. %	Power %	Neg %	Average Buzz
2025 ACF Nationals	Yes	24	96%	0%	21%	93.78