UC Engineers Design A Quieter Future For Drones And Flying Cars- Drivepilots.com

Aerospace engineering students at the University of Cincinnati are studying sound mitigation solutions at UC’s College of Engineering and Associate Professor of Applied Science, Daniel Capoletti.  If flying cars are to be successful, Capoletti said, they have to be quiet.

 Daniel Cappoletti, a professor of aerospace engineering at the University of Cincinnati, uses an anechoic chamber enclosed in sound-absorbing panels to study engine and propeller sound in drones and flying cars. 

 Noise is an obstacle to making a dream of flying cars – imagine the noise emanating from the hundreds of mixers in your kitchen at one time.

Humans can usually perceive sounds at frequencies between 20 and 20,000 cycles per second,

Solar surface noise will be approximately 100dB by the time it reaches Earth.

 It’s not just flying vehicles but drones as well.  Complaints about the high-end of propellers may lead to restrictions or regulations that prevent the growth of the new commercial drone industry.

  UC Aerospace Engineering students Natalie Reid, Matthew Walker and Peter Sorensen presented papers this month with Cappoletti at the Science and Technology Forum and Exhibition in San Diego, California.  Hosted by the American Institute of Aeronautics and Astronautics, it is the world’s largest aerospace engineering conference.

 “I see the noise from social impact,” said Cappoletti.  “These vehicles must be incomprehensible in the environment in which they fly or someone has to take the burden of that impact.”

 Often, the effect is felt in low-income neighbourhoods, he said.

 Daniel Cappoletti, an associate professor at the University of Cincinnati and his students, uses laser light to study the properties of propellers.  Credit: Andrew Higley / UC Creative

 Airports around the country have been the subject of tens of thousands of noise complaints a year from aggravated residents.  In an FAA survey published last year, two-thirds of respondents said they were “more annoyed” by the noise of the aircraft.  The survey found that the noise of planes and helicopters was far more annoying than cars, trucks or neighbours.

 Likewise, engine noise is a big concern for military and commercial aviation.  U.S.  Hearing loss and tinnitus are the leading causes of medical disability claims filed with the Department of Veterans Affairs.

 Drones do not pose the same risk of hearing loss as larger aircraft because they are not much louder than kitchen equipment.  But the unique quality of their buzzing rotors stands out against the ambient background, which makes them annoying and distracting.

 “A helicopter flies over your roof,” Capoletti said.  “If you want 1,000 drones to fly over cities, noise is a big problem.”

 The potential aggravating factor is the absolute magnitude.  The United States sees about 5,700 commercial flights daily, with drones capable of thousands of flights to major cities every day with their diverse applications.

 Capoletti said different factors influence the way people perceive sound.  Aeroplane noise is less noticeable in congested cities than in suburbs or rural areas.  And time of day is also important.  The evenings are quieter, making the flight more noticeable.

 Researchers at the University of Cincinnati’s College of Engineering and Applied Science are studying drones that are quieter and less intrusive.  Credit: Andrew Higley / UC Creative

 “Studies have found that just looking at a plane can make people feel louder,” Cappoletti said.  “There are subjective human factors that you can’t control.”

 Cappotelli is studying how to handle sound from drones through engineering design.  He examines the sound in a room paired with sound-absorbing padding to relieve the echo.

 Using an anechoic chamber, covered with sound-deflector on all sides and equipped with a suite of eight microphones, Kapoletti examines the frequency, frequency, and amplitude of sound, among other factors, affecting our perception of sound.  He and his students are developing a guidebook that drones and flying car manufacturers can use to anticipate how their novel designs will sound based on UC’s engineering and physics experiments.

 Each rotor has its own noise signature.  UC student Reid said that by changing the configuration of two rotors, 10 decibels or more could be added or reduced.

We humans can hear sounds from 0 to 140 decibels.  0 does not mean that no decibel sounds, just that we cannot hear it.  0 The decibel is called the hearing threshold for the human ear

 She examined 16 rotor configurations for the paper presented at the SciTech conference.

 “Changing the vertical distance affects the sound. So I see what happens if we change the vertical or horizontal spacing,” he said.

 For drones to be part of everyday life, they must be quiet.  Aerospace engineers at the University of Cincinnati are working to make it happen.  Credit: Andrew Higley / UC Creative

 UC student Sorensen studied the differences in the sound of rotors rotating in the same direction against opposite directions: co-rotation or counter-rotation.  So far, the results are inconclusive.

 As flying cars take wildly imaginative forms on the drawing board, UC engineers hope to help create quieter designs.

 “This is a very thrilling time for aerospace,” Kappoletti said.  “The new aircraft designs are in the preliminary and conceptual design stages.

 UC’s sound experiments help manufacturers make more informed design decisions, he said.

 Sources by the University of Cincinnati

FAQ

Q).How much db can a man sound?

  We humans can hear sounds from 0 to 140 decibels.  0 does not mean that no decibel sounds, just that we cannot hear it.  0 The decibel is called the hearing threshold for the human ear

Q).What is the safest sound limit for the humans Can hear?

Ans.  Any exposure to sounds greater than 140 dB is considered unsafe for humans, and constant exposure to sounds greater than 85 dB could endanger your hearing.

 Q). What is the loudest noise?

  Ans. At 10.02 am on August 27, 1883, the largest sound in recorded history came from a volcanic eruption on the island of Krakatoa, Indonesia.  The explosion caused two-thirds of the island to collapse, and a 46-m (151-foot) tsunami generated rocking ships.