Making UAM vehicles quieter during takeoff, landing

High noise levels during flight have been a barrier to advancing urban air mobility (UAM) vehicles, or air taxis. Thanks to new research being conducted at Embry-Riddle Aeronautical University and backed by a recently awarded $1.4 million NASA grant, low-noise multirotor aircraft may become a reality.

Working with Boston University, Virginia Tech, Tuskegee University, and Joby Aviation, a team led by Dr. Vladimir Golubev, Embry-Riddle professor of Aerospace Engineering and a principal investigator on the project, will focus on how air taxis can take off and land quietly at vertiports located in dense urban environments where wind gusts tend to be unpredictable. These turbulent flight conditions present unique aerodynamic and aeroacoustic challenges.

“Those need to be controlled through development of accurate response-prediction tools and optimization strategies,” Golubev says.

During the three-year project, the team will provide guidance on suitable locations for city-based rooftop vertiports and flight corridors that would minimize noise during takeoff and landings.

“Noise is a critical aspect for public acceptance,” Golubev says of electric-powered UAM vehicles, noting that major strides have already been made to mitigate sound and pressure levels.

Last year, NASA and Joby Aviation released preliminary findings from a simulation to capture noise profile data from a full-size UAM prototype. A remotely piloted aircraft loaded to near-maximum weight capacity (the equivalent of a pilot plus four passengers) was flown during a two-week test period at Joby’s Electric Flight Base in California. The aircraft registered decibel levels almost 1,000x (30dB) quieter than that of a typical helicopter.

Embry-Riddle’s research, conducted as part of NASA’s University Leadership Initiative, will address the sustainability of such noise reduction in highly unsteady flow conditions. Work will be led by Golubev, along with co-principal investigators Dr. Tasos Lyrintzis, distinguished professor and chair of the Aerospace Engineering Department, and Dr. Reda Mankbadi, distinguished professor. Four Ph.D. candidates and several undergraduate students will also be involved.

Graduate students will create computational simulations of noise aerodynamics and control multi-rotor vehicles in urban environments.

By focusing on the sound levels associated with UAM’s vertical lift capabilities, the team hopes to reduce the environmental impact of these vehicles, helping ease their entry into new markets.

“Their work will also provide critical insight that improves safety and ride quality for passengers,” says Dr. Jim Gregory, College of Engineering dean.

An outreach program will be developed to raise awareness and educate the community on how this emerging technology will be incorporated safely into our skies.

Work on the project will begin in September.