(Press-News.org) "Splashing" plays a central role in the transport of pollutants and the spread of diseases, but while the sight of a droplet striking and splashing off of a solid surface is a common experience, the actual physical ingredients and mechanisms involved in splashing aren't all that well understood.
A team of Brown University and Harvard University researchers has discovered that there is indeed more involved in splashing than previously believed. They will discuss their findings at the upcoming American Physical Society's 64th Annual Division of Fluid Dynamics Meeting, which will be held Nov. 20-22, 2011, in Baltimore, Maryland.
"In recent studies, it was highlighted that the surrounding air plays an important role in the splashing process. Decreasing the ambient pressure inhibits splashing," explains Julie Albagnac, a postdoctoral research associate in engineering at Brown. "The observations led to a hypothesis of the existence of a thin layer of air trapped between the drop and the surface."
To better understand droplet splashing, the researchers initially wanted to observe and measure this layer of trapped air. They hypothesized that splashing may occur even before actual contact of the drop on the surface, while the drop is still spreading on an air film.
Unfortunately, they found that experimental equipment available today isn't sophisticated enough to catch a length as small as the air layer thickness (hundreds of nanometers) during the short time of existence of this air layer (hundreds of nanoseconds). So they instead studied the time evolution and behavior of droplets splashing with various impact velocities under a variety of ambient pressures to examine different scenarios involving splashing.
For this purpose, experiments performed at Harvard provide side and bottom views of the droplets. "This study shows a new signature of a precursor to the splashing through the wriggling of the contact line at the interface between the droplet and the surface," says Albagnac.
The splashing/spreading of a droplet doesn't seem to be an on/off situation, according to the team. A transition regime exists between the spreading and splashing, which they observed by changing either the impact velocity or the ambient pressure while the other is fixed.
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MORE MEETING INFORMATION
The 64th Annual DFD Meeting is hosted by the Johns Hopkins University, the University of Maryland, the University of Delaware and the George Washington University. Howard University and the U.S. Naval Academy are also participating in the organization of the meeting. It will be held at the Baltimore Convention Center, located in downtown Baltimore, Md. All meeting information, including directions to the Convention Center, is at: http://www.dfd2011.jhu.edu/index.html
USEFUL LINKS
Main Meeting Web Site: http://www.dfd2011.jhu.edu/index.html
Search Abstracts: http://meeting.aps.org/Meeting/DFD11/Content/2194
Directions and Maps: http://www.dfd2011.jhu.edu/venuemaps.html
PRESS REGISTRATION
Credentialed full-time journalists and professional freelance journalists working on assignment for major publications or media outlets are invited to attend the conference free of charge. If you are a reporter and would like to attend, please contact Charles Blue (cblue@aip.org, 301-209-3091).
SUPPORT DESK FOR REPORTERS
A media-support desk will be located in the exhibit area. Press announcements and other news will be available in the Virtual Press Room (see below).
VIRTUAL PRESS ROOM
The APS Division of Fluid Dynamics Virtual Press Room features news releases, graphics, videos, and other information to aid in covering the meeting on site and remotely. See: http://www.aps.org/units/dfd/pressroom/index.cfm
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A holiday Open House hosted by Le Dimora and Jimmy Choo will be held at the Le Dimora interior design boutique located at 16089 San Dieguito Road in Rancho Santa Fe (Del Rayo Village Shopping Center) on the evening of Thursday, December 1, 2011 from 6:00 pm to 8:30 pm to launch the Jimmy Choo Cruise 2012 Collection and raise funds for the Jammer Family Foundation. Guests will savor appetizers provided by Sushi on the Rock and sip champagne while shopping for shoes, handbags and interior decor items in a festive holiday atmosphere. A percentage of all sales from the event ...
The structure of the corpus callosum, a thick band of nerve fibres that connects the two halves of the brain with each other and in this way enables the rapid exchange of information between the left and right hemispheres, plays an important role in the regaining of motor skills following a stroke. A study currently published in the journal Human Brain Mapping has shown that in stroke patients with particularly severely impaired hand movement, this communication channel between the two brain hemispheres in particular was badly damaged.
In order to relate brain function ...
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"One may easily picture that a raindrop impacting a contaminated leaf grabs some of the pathogens there before being ejected and flying towards some healthy ...
The ability to efficiently and unobtrusively screen for trace amounts of explosives on airline passengers could improve travel safety – without invoking the ire of inconvenienced fliers. Toward that end, mechanical engineer and fluid dynamicist Matthew Staymates of the National Institute of Standards and Technology in Gaithersburg, Maryland, and colleagues have developed a prototype air sampling system that can quickly blow particles off the surfaces of shoes and suck them away for analysis.
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Broward SCORE will launch in December special digital editions of its upcoming winter workshops for 2012 designed for smart phones and tablets.
SCORE enlisted the expertise of Guni Bermudez of Reach MCS and Jeff Miller of Stallion Publishers, both based in Fort Lauderdale, to create the new platforms. The Broward chapter of SCORE, a resource partner with the SBA, tested its digital editions in the fall, working out the kinks and improving the user experience.
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Fluid dynamicists have long observed that orbital shaking generates a wave that propagates around the inner edge of the glass, churning the liquid as it travels. "The formation of this wave has probably been known since the introduction of glass or any other kind of cylindrical bowl, but what has been lacking is a description of the physics related to the mixing ...
KINGSTON, R.I. – November 21, 2011 – A nest containing the fossilized remains of 15 juvenile Protoceratops andrewsi dinosaurs from Mongolia has been described by a University of Rhode Island paleontologist, revealing new information about postnatal development and parental care. It is the first nest of this genus ever found and the first indication that Protoceratops juveniles remained in the nest for an extended period.
The findings were reported in the most recent issue of the Journal of Paleontology.
David Fastovsky, URI professor of geosciences, said the bowl-shaped ...
In the early '90s, a Department of Defense engineer at NASA assigned to work on the now defunct Super Conducting Super Collider project was sidetracked with a personal mission that had nothing to do with subatomic particles or electromagnetic fields. Instead, after federal budget cuts ended the project, Ron Green assigned himself an entirely new operation: hatching up the country's perfect breakfast, brunch and lunch restaurant concept.
Mission accomplished. Today, Another Broken Egg Cafe cracks more than 900,000 eggs a week at its 18 bustling locations in seven states, ...
Alexandria, VA – Is the United States entering its "Lost Decade"? A crunch on natural resources coupled with a crippling economic crisis and an aging workforce threaten to hurl us into a decade—or more—of grudgingly slow development akin to that of the Japanese after their own real estate bust a few decades ago. Will the United States learn from past mistakes in order to reconcile economic growth with environmental safety? In the December issue of EARTH Magazine, learn how the facts and the fallacies measure up to the increasing challenges facing the United States in 2012 ...
INDIANAPOLIS — The scoring system government agencies use to rate nursing home quality does not provide an adequate evaluation because they do not take into account the degree of cognitive impairment of their patient populations and whether facilities include a specialized dementia unit according to a new study.
Focusing on statistics from Minnesota, researchers from Indiana University School of Medicine and the Regenstrief Institute report on the inadequacy of quality of care indicators for nursing home residents with behavioral and psychological systems related to dementia ...
