While the crowds at the JenningsGP racetrack in north Florida enjoyed exciting motorcycle races, Bill Brown, the racetrack’s executive director, was fielding complaints about the noise from nearby residential neighborhoods. Wanting to be a good community partner, Brown turned to the Space Alliance Technology Outreach Program (SATOP) to help lessen the racetrack’s noise output and put an end to complaints from neighboring homeowners.
The racetrack already had measures in place to prevent excessive noise, including an earthen berm that extended 14 feet above the track base. However, the berm was not fully effective because it did not completely surround the track. Brown had considered making some costly modifications to the existing berm design, but he was unsure of the best solution to his challenge.
“I needed to find a way to reduce noise transmission from my track and to prevent future noise problems,” said Brown. “Some of my employees had heard about SATOP’s ability to solve acoustical challenges, and they recommended that I contact the program for help.”
Brown’s Request for Technical Assistance (RTA) was assigned by SATOP to Ed O’Keefe, Associate Technical Fellow of Acoustics and Vibration with The Boeing Company at the NASA Johnson Space Center (JSC). Based on Brown’s photographs of the track and its surrounding topography, O’Keefe was able to determine the factors contributing to the higher level of noise coming from the track.
After about 40 hours of work, O’Keefe developed an analysis of the track design that addressed the effectiveness of the berm and the effects of erosion, methods to improve the berm and to mitigate erosion, and the contribution of natural foliage to overall noise reduction.
“I developed a mathematical model that would demonstrate different noise levels as related to changes in the berm design,” said O’Keefe. “Using this model, I was able to show that Mr. Brown’s proposed changes would not be as effective as other minor modifications to the berm.”
O’Keefe also recommended specific materials to increase the berm’s effectiveness, and he provided a minimum berm height to ensure that the racetrack will no longer be a source of unacceptable noise levels. Based on this information, JenningsGP extended the original berm 150 feet and added a wall to the top to curve the noise transmission inward.
“This study not only saved JenningsGP from unnecessary spending, but it also alerted them to the need to monitor berm erosion,” said O’Keefe.
Brown also is very pleased with the recommendations he received through SATOP to lower the noise levels of his racetrack, and JenningsGP will conduct
a final test of the solution early this year. “I was very surprised with how quickly SATOP came up with a simple solution to my situation,” Brown said. “We would not have known what to do without the help from this program and the technical expertise it provides.”