February 11, 2013
Aerospace engineering doctoral candidate Woutijn Baars and faculty advisor Dr. Charles Tinney are working on a research project that may help to better the lives of many United States military personnel and veterans.
The second most number of claims to the United States Department of Veteran Affairs has been for hearing loss. When military jets take off from aircraft carriers, the sound can be deafening. The acoustic load is sometimes so intense that ear protection does not always adequately protect from hearing loss.
To combat this problem, the Office of Naval Research initiated the long-term Jet Noise Reduction Program. One of the goals of the program is to understand the physics of jet noise that is produced by military-style jet engines. Insight into these physical mechanisms will allow researchers to develop strategies to efficiently reduce the noise. In turn, this could improve the quality of life for many military personnel.
Thanks to funding from the Office of Naval Research and the Air Force Office of Scientific Research, Baars and Tinney are currently working on a jet noise project. They use several miniature microphones to measure the sound waves emitted by the jet flow. A detailed survey of these recordings at specific locations provides them with data. They are then able to quantify the jet noise.
All the information they acquire is necessary for developing effective control strategies for eliminating the noise that is perceived as being the loudest and most annoying. ‘Crackle’ is one of these noise components; it is very distinct noise embedded within the regular noise from jets, which sounds like an arc welder or badly connected loudspeaker. When the jet noise community is able to eliminate that noise component, a large reduction in jet noise from military type aircrafts will be achieved.
The test facility at Pickle Research Center where these acoustic tests are performed is unique – no other university has the test rig and anechoic chamber needed to conduct them. Baars played a significant role in designing and building the Multidisciplinary Fluid Dynamics Lab that is a one of a kind research facility.
“When I came to UT, Dr. Tinney was a new faculty member, and he was in the process of designing and constructing the anechoic (echo-free) fluid dynamics facility. I had the opportunity to take on a unique responsibility of designing and building a modular test rig within that facility in addition to doing research.”
Baars attributes his outstanding experience at UT to strong research collaboration with other institutes and his ability to attend many conferences to present his work.
“As a student, I had the opportunity to build a network of contacts. I met with people at NASA Marshall Space Flight Center, the National Center for Physical Acoustics, and more. I gave them presentations and we started collaborating and sharing data sets and equipment. We also wrote papers with them.”
Baars first became acquainted with the ASE/EM Department when he came to UT from Delft University of Technology to perform research as a master’s exchange student during the 2008-2009 academic year. Tinney co-supervised Baars’ thesis. When Baars traveled back to his native Netherlands to present his thesis, Tinney came to be a part of his committee. Two weeks later, Baars moved to Austin to begin pursue his PhD under the direction of Tinney.
“My graduate studies here have allowed me to become an independent researcher,” Baars said. “We started from scratch, we designed and built our facility, ran our experiments, and set up collaborations with other institutes. I’ve presented at eight internationally recognized conferences. People know who I am already. I never would have thought that was possible four years ago.”
Baars plans to graduate this May. He plans to enter academia to continue researching and teaching.
