Nav: Home

Erosion has a point -- and an edge, NYU researchers find

November 12, 2012

Erosion caused by flowing water does not only smooth out objects, but can also form distinct shapes with sharp points and edges, a team of New York University researchers has found. Their findings, which appear in the latest edition of the journal the Proceedings of the National Academy of Sciences (PNAS), reveal the unexpected ways that erosion can affect landscapes and artificial materials.

The impact of erosion is widely recognized by environmentalists and geologists, but less clear is how nature's elements, notably water and air, work to shape land, rocks, and artificial structures, often resulting in unusual formations.

"The main focus of this study was to understand how and why erosion makes these funny shapes," explained Leif Ristroph, a post-doctoral researcher at NYU's Courant Institute of Mathematical Sciences and one of the study's co-authors.

To explore these questions, the researchers designed an experiment, conducted in the Courant Institute's Applied Mathematics Laboratory, to replicate natural erosion. In it, the researchers submerged clay--shaped as balls or cylinders--into a 15-ft. long water tunnel. The apparatus was designed to continuously generate a uniform flow of water, which would allow the researchers to observe how erosion shapes an entire object.

What they found was water flow acts as a shearing force--not unlike a nail file--against objects, working them into specific shapes. Starting from a clay ball, the flowing water sheared the sides away, producing a cone with a pointed face. Likewise, the clay cylinder was sculpted into a triangular shape. The researchers then sought to confirm these findings by replicating the experiment using a computer model. These results were consistent with the experimental findings, revealing in a computer simulation how the shape was maintained as the body eroded away.

"Water acts tangentially to the surface of objects and skims off material to create these unique shapes," explained Ristroph. "In a sense, it works as a sculptor to naturally mold materials into new forms."
-end-
The study's other co-authors were: Matthew Moore, a Courant post-doctoral fellow; Courant Professors Stephen Childress and Michael Shelley; and Jun Zhang, a professor at the Courant Institute and NYU's Department of Physics.

The research was supported by grants from the U.S. Department of Energy (DE-FG02-88ER25053) and the National Science Foundation (DMS-1103876, MRI-0821520).

New York University

Related Erosion Articles:

Landscape-scale erosion instabilities in the northern Gabilan Mesa, California
If you ever fly from L.A. to San Francisco, California, you may notice the Gabilan Mesa off to the east as you begin your descent into San Francisco International Airport.
Pasture management and riparian buffers reduce erosion
A 12-year study was completed in Arkansas watersheds.
More than 100 years of flooding and erosion in 1 event
Sara Rathburn of Colorado State University and colleagues have developed an integrated sediment, wood, and organic carbon budget for North St.
Studying midwest soil production, erosion and human impacts
Larsen and colleagues will study Midwest soils where remnants of the native prairie still exist, specifically in Iowa, Illinois, Minnesota, Nebraska and South Dakota.
Research assesses impact of soil erosion on land and communities in East Africa
The impact of soil erosion on both the environmental and social well-being of communities in East Africa is to be explored in new research led by the University of Plymouth.
New study shows ocean acidification accelerates erosion of coral reefs
Scientists studying naturally high carbon dioxide coral reefs in Papua New Guinea found that erosion of essential habitat is accelerated in these highly acidified waters, even as coral growth continues to slow.
Deepwater Horizon oil spill caused widespread marsh erosion
Marsh erosion caused by the 2010 Deepwater Horizon oil spill was widespread, a new study of 103 Gulf Coast sites reveals.
New insights on the relationship between erosion and tectonics in the Himalayas
Can processes unfolding at the Earth's surface be strong enough to influence tectonics?
Huge time-lag between erosion and mountain building
An unprecedented record of erosion rates dating back millions of years shows a significant time-lag between tectonic uplift and maximum erosion rates in the Argentine Precordillera mountains.
Beach replenishment helps protect against storm erosion during El Niño
Sand added to three San Diego County beaches in 2012 has partially remained, surviving the large waves of the El NiƱo winter of 2015-16.

Related Erosion Reading:

Erosion: Changing Earth's Surface (Amazing Science)
by Robin Koontz (Author), Matthew Harrad (Illustrator)

Cracking Up: A Story About Erosion (Science Works)
by Jacqui Bailey (Author), Matthew Lilly (Illustrator)

Weathering and Erosion (Science Readers: Content and Literacy)
by Torrey Maloof (Author)

Erosion (Reading Essentials in Science)
by Virginia Castleman (Author)

Soil Erosion and How to Prevent It (Everybody Digs Soil)
by Natalie Hyde (Author)

Erosion and Weathering (Rocks: The Hard Facts)
by Willa Dee (Author)

Erosion (Let's Explore Science)
by Shirley Duke (Author)

Erosion: How Land Forms, How It Changes (Exploring Science: Earth Science)
by Darlene R. Stille (Author), Farhana Hossain (Illustrator)

Dirt: The Erosion of Civilizations
by David R. Montgomery (Author)

Erosion (Princeton Series of Contemporary Poets)
by Jorie Graham (Author)

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

The Right To Speak
Should all speech, even the most offensive, be allowed on college campuses? And is hearing from those we deeply disagree with ... worth it? This hour, TED speakers explore the debate over free speech. Guests include recent college graduate Zachary Wood, political scientist Jeffrey Howard, novelist Elif Shafak, and journalist and author James Kirchick.
Now Playing: Science for the People

#486 Volcanoes
This week we're talking volcanoes. Because there are few things that fascinate us more than the amazing, unstoppable power of an erupting volcano. First, Jessica Johnson takes us through the latest activity from the Kilauea volcano in Hawaii to help us understand what's happening with this headline-grabbing volcano. And Janine Krippner joins us to highlight some of the lesser-known volcanoes that can be found in the USA, the different kinds of eruptions we might one day see at them, and how damaging they have the potential to be. Related links: Kilauea status report at USGS A beginner's guide to Hawaii's otherworldly...