Overpressure

About: Overpressure is a research topic. Over the lifetime, 3236 publications have been published within this topic receiving 34648 citations.

The Challenges of Defining an Acceptable Sonic Boom Overland

Abstract: Sonic boom is the ground trace of the pressure disturbance created by the passage of an aircraft, or any other object, flying faster than the speed of sound. A typical conventional (non-minimized) sonic boom time waveform measured at the ground looks roughly like the letter N see Fig.(1) as an example and hence is commonly called an N wave. The distinctive characteristics of conventional sonic booms compared to other types of noise are : 1) the presence of two (or more) shock waves, e.g., large and sudden pressure variations that may be perceived like detonation noise (sonic boom is sometimes also called ”ballistic detonation”) ; 2) the slow variations in time of the part of the sonic boom between the shock waves. This portion of the waveform is slow enough to be inaudible by the human ear. However, because low frequency energy is present, it may induce some indirect noise and other non-audible effects that should be considered when assessing human acceptability to sonic boom. So sonic boom is characterized as simultaneously a loud, low frequency and impulsive noise (according to the definition of CHABA). It is impulsive because of its short duration (of the order of 0.1 to 0.3 ms, closely related to the length of the aircraft) with a relatively distinct termination (the last shock). Moreover the pressure increase through the shock waves takes place over a very short time, defined as the rise time, which is of the order of a few milliseconds. It is loud because of the overall peak overpressure is of the order of 50 to 100 Pa (1 to 2 psf). It is low frequency because the main part of its frequency spectrum is in the infrasonic or low audible frequency range (1-30 Hz) see the pressure spectrum in Fig.(1).

Some Effects of Applying Sonic Boom Minimization to Supersonic Cruise Aircraft Design

Abstract: This paper presents a discussion of an aircraft shaping method to control sonic boom overpressure levels along with the analysis of wind tunnel data which validated the method. The results indicate that the sonic boom minimization method can guide the design team choices of aircraft planform and component arrangement toward a low-boom-level configuration while permitting sufficient freedom and flexibility to satisfy other design criteria. Further, it is shown that off-design flight conditions do not drastically change the overpressure sonic boom shape and strength.