Featured Research

from universities, journals, and other organizations

Aerospace Research Provides New Understanding Of Atmospheric Turbulence

Date:
July 7, 1997
Source:
University Of Cincinnati
Summary:
With a sudden and powerful "boom", University of Cincinnati graduate student Donald Freund has found a way to simulate one of the most undesirable conditions a supersonic jet aircraft can face: flying into rapid, severe changes in the atmosphere.

Cincinnati -- With a sudden and powerful "boom", University of Cincinnati graduate student Donald Freund has found a way to simulate one of the most undesirable conditions a supersonic jet aircraft can face: flying into rapid, severe changes in the atmosphere.

His data will help engineers improve the computer codes they use to develop propulsion systems for future high-speed aircraft. Freund will explain his experiments and present his data during the American Institute of Aeronautics and Astronautics (AIAA) Joint Propulsion Conference July 6-9 in Seattle.

The "boom" is a large amplitude "acoustic disturbance" in aerospace terms and is used to simulate severe atmospheric turbulence in the laboratory. The difficulty in setting up the experiment was not only generating the boom, but generating it quickly enough to simulate real-world conditions. Freund solved the problem with a novel device nicknamed the "bump." The details are described on Freund's World Wide Web home page at http://www.ase.uc.edu/~dfreund/research.htm.

Freund records the "acoustic reflection coefficients," a measure of how much of the boom is reflected back from the engine. Freund is developing a huge database, showing what happens under various engine operating conditions. Current computer codes rely on approximations to simulate the reflection process, but Freund discovered that these approximations are not even close to simulating what really happens.

"We found that the reflection comes from a number of stages of the compressor, drastically different from what people were assuming in the past. The amplitude of the reflection is considerably less than what they predict, and it's considerably longer than what they would predict."

The information also solves a long-standing problem in high-performance aircraft design. Armed with Freund's data, designers now can modify their codes to predict more accurately how a system will respond to severe atmospheric turbulence.

"Once you get the information, it becomes the glue that allows designers to take their inlet code and a compressor code that are normally operated by different people and different companies and make them talk to each other," said Miklos Sajben, Freund's adviser and Ohio Eminent Scholar of Aerospace Engineering. "It's like finding an interpreter for two people who can't speak each other's language." Sajben also believes the findings will have a lasting impact on how such computations are performed in aerospace engineering practice.

The work has attracted the attention of aerospace companies and of NASA. Sajben has been awarded a multi-year grant by NASA to use a very similar experimental rig (that uses much of Freund's system) to study another type of atmospheric disturbance involving temperature gradients. "The next project is to see what happens if the engine swallows a big hunk of hot air," said Sajben. "That can create similar problems, and it is a common event."

Freund's unique experimental setup and research findings earned him the 1997 Gordon C. Oates Air Breathing Propulsion Graduate Award from the AIAA Foundation. Freund will be presented with his award and a $5,000 check during the AIAA conference. He will present his research results as part of the general meeting and again during a special invited talk as part of the award presentation.

Freund is a native of Macon, Georgia and a graduate of Centerville High School near Dayton Ohio.

###


Story Source:

The above story is based on materials provided by University Of Cincinnati. Note: Materials may be edited for content and length.


Cite This Page:

University Of Cincinnati. "Aerospace Research Provides New Understanding Of Atmospheric Turbulence." ScienceDaily. ScienceDaily, 7 July 1997. <www.sciencedaily.com/releases/1997/07/970707211338.htm>.
University Of Cincinnati. (1997, July 7). Aerospace Research Provides New Understanding Of Atmospheric Turbulence. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/1997/07/970707211338.htm
University Of Cincinnati. "Aerospace Research Provides New Understanding Of Atmospheric Turbulence." ScienceDaily. www.sciencedaily.com/releases/1997/07/970707211338.htm (accessed July 31, 2014).

Share This




More Earth & Climate News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com
Big Waves In Arctic Ocean Threaten Polar Ice

Big Waves In Arctic Ocean Threaten Polar Ice

Newsy (July 30, 2014) Big waves in parts of the Arctic Ocean are unprecedented, mainly because they used to be covered in ice. Video provided by Newsy
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins