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35
st, 0 Bank (1965)
'
in
low amplitude (generated using the low-boom dive maneuver) E . 0
to higher amplitude from conventional overflight and military z>- 2°
operations in the area (Fidell et al., 2012; Page et al., 2014). .5 0°
The WSPR program addressed the following: (1) design E In a . 0
a.nd development of an experimental design to expose 9 :7
people to low-amplitude sonic booms; (2) development and 5 e o . o ' .
implementation of methods for collecting acoustical measures em 45 Se is 60 is 70
of the sonic booms in the neighborhoods where people live; CDNL (d.B)
(3) ‘leslgll “ml “‘ll“ll‘l5l”ll°“ °f ‘°°l“l ‘““'°V‘ l° l“°““'° Figure 3. Dnse—resp1mse dutu frnm the wuvefnrms and szmic banm
P°°P1“’5 ’“‘“°“5 ‘° 5°'“‘ l’°°'“5? “ml (4) “5“5'“°'“ °f pmepmm and respnnse pmgmm (WSPR) 2011 study (Lnulzeau.
the effectiveness of Wrious elements of the experimental 2013) cnmpured with data /mm 1119605 snnic imam field study (aw
design and execution to inform future, wider scale testing. sky, 1965). CDNL, C—weighter1duy—r1ightlevel.
Sonic boom measurements were gathered in the residential
community and statistical methods were developed for
assessing the subjective response t°1t,wbt,°ms_ waves are turned upward before reaching the ground. The
speed at which this occurs is referred to as the Mach cutoff
The sublecllve response dalaqhalysls methods allow lhe and is a function of the atmospheric conditions and flight
identification of dose-response curves relating annoyance to altitude Much eutotf eeiiee on the fact that tb e SP e e d of
the noise exposure, although this particular dataset reflects sound at flight altitude is lower than that on the ground
responses {mm all acclllhaled Commlmlly and mlghl not due to the colder upper air temperatures. The possibility
be reflective of people living in areas not routinely exposed is being explored of mixed Mach number eouveutioual
to sonic booms. Single-event dose-response curves were N_waVe eiesieu aircraft that will fly just below Maeb eutotf
obtained for avariety of noise metrics using measured noise over iaud tuomiuaiiy between Maeb 1'0 and 1.15) aud at
levels from a distributed set of noise monitors. Another bigbet suueesouie eueeds over water where supersonic flight
important element of the WSPR test was the consideration of is not Currently ueobibit e d ( Mutisb e eke 2017). Eveu though
not only ll 5lllgle'eVelll response but also a daily Cllmlllallve the sonic boom itself does not reach the ground when flying
response and hence was designed to take into account the beiow the Mach eutoffi some of the eueeey from the souie
number of dally Polehllal flllllle sllpelsolllc °Pelall°h5' boom pressure disturbance transitions into an ewnescent
Pasl sllldles (Sala'lh°lle‘ 2009; Rachaml and Page‘ 2010) wave, passes into the shadow side, and can reach the ground
sllggesled lllal ll vallely lll lhe numb" of exposures would as an acoustic signal where it often sounds like rumbling
be expected across the United States from future operations, oi, distant thunder. The NASA faufieiei iuveetigatiou of uo_
wllh ll maxlmllm of“? lo l2 solllc booms dally‘ boom thresholds (Fa.lNT) test captured an empirical dataset
To understand the cumulative impacqs, cumulative of these evanescent waves (Cliatt et al., 2016).
exposures were Computed (C'welghled DNL‘ CDNL) for llle Analysis of the Mach cutoff (Plotkin et al., 2008) has
WSPR Partlclpmls and Compared wlth Pllol sohlc boom examined the viability of Mach cutoff flights across the
sllldleslllthe U605 and l970s‘A“examPle Compallsoh oflllese United States, while recent research funded by the Federal
dam lhoubeau’ 2013) to hlslollcal dala (Bolskll U65) ls show“ Aviation Administration (FAA) has explored the sensitivity
ll‘ Flgllfl 3‘ whlcll Presents the Pelcehlage of lesl sllblecls who of different atmospheres on overpressure and loudness levels
were hlgllly almoyed by the days boom evellls as ll hlhctloll °f (Busch et al., 2017). As a consequence, efforts are underway
CDNL for each day‘ Allllollgh the WSPR sllldy was Plllllallly to investigate human perception of these Mach cutoff sounds
a methodological test i.n preparation for future studies with a (Ortega et at, 2018) usiug the Fa_iN-i- dataset.
low-boom demonstrator aircraft, the daily annoyance results
are remarkably similar to those from the 1965 Borsky report. scenic Bonn,‘ lvlaterica
Mach Cutalf There is a need to identify noise metrics to quantify the
It is possible to fly supersonically without creating an noise exposure in dose-response curves of community test
audible sonic boom on the ground by taking advantage data. These metrics, which can leverage existing metrics for
of atmospheric refraction where the sonic boom pressure commercial, military, and impulsive noise sources, must
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