3-D Acoustic Ray-Tracing Model of Mach Cutoff Flight
Open Access
- Author:
- Huang, Zhendong
- Graduate Program:
- Acoustics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- October 15, 2020
- Committee Members:
- Victor Ward Sparrow, Dissertation Advisor/Co-Advisor
Victor Ward Sparrow, Committee Chair/Co-Chair
Philip John Morris, Committee Member
Michelle Celine Vigeant, Committee Member
Yvette Pamela Richardson, Outside Member
Victor Ward Sparrow, Program Head/Chair - Keywords:
- Mach cutoff flight
sonic booms
ray tracing - Abstract:
- Mach cutoff flight is achieved when a supersonic airplane operates in a narrow speedaltitude envelope just above Mach 1, intending that no sonic boom directly impacts the ground. In this research, a 3-D ray-tracing algorithm has been developed for an acoustical model of Mach cutoff flight, which is capable of reading in realistic atmospheric data that includes 3-D speed of sound variations as well as 3-D winds, and tracing the sonic boom ray trajectories under given flight conditions. This algorithm is then used to study the impact of atmospheric conditions on the operations of Mach cutoff flight. To provide a statistical prediction of the viability of Mach cutoff flight, ray-tracing simulations are run in parallel using the cloud computing service provided by the ICDSACI at Penn State. The simulations include the three busiest air routes, two flight altitudes, two safety margins, as well as 80 realistic atmospheric profiles in the year of 2017 produced by the High-Resolution Rapid Refresh (HRRR) model, to come up with predictions of the cutoff Mach number and aircraft ground speed for each case. Finally, the minimum, maximum, mean, and standard deviation of the cutoff Mach numbers and aircraft ground speeds are calculated over 80 weather situations. It is shown that most of the time the Mach cutoff operation can successfully prevent focused sonic booms from reaching the ground. In order to achieve higher Mach cutoff speeds, it’s crucial to have frequently updated atmospheric profiles with high resolution. Enabling Mach cutoff is much easier whenever there is a headwind, and it’s not always possible to have a Mach cutoff operation with a tailwind. In the situation when an aircraft can obtain atmospheric data that’s updated at least hourly, then most of the time it’s possible to have an eastbound flight (with a tailwind) at Mach 1.05 without having a direct sonic boom reaching the ground. This number can be as large as Mach 1.15 for a westbound flight (into a headwind). [This work was funded by the U.S. Federal Aviation Administration (FAA) Office of Environment and Energy as a part of ASCENT Project 42. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the FAA or other ASCENT Sponsors.]