Ground Measurements of a Shaped Sonic Boom

Plotkin, Kenneth J.; Page, Juliet A.; Graham, David H.; Pawlowski, Joseph W.; Schein, David B.; Coen, Peter G.; McCurdy, David A.; Haering, Edward A.; Maglieri, Domenic J.; Pilon, Anthony R.; Salamone, Joe; Murray, James E.; Ehernberger, L. J.; Bobbitt, Percy J.

doi:10.2514/6.2004-2923

Cited by 12 publications

(6 citation statements)

References 6 publications

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“…Flight-test results [25] indicated that the flat-top waveform persisted in spite of a distorted waveform due to the turbulence interaction; thus, the sonic boom reduction due to the geometric modification was demonstrated. However, the distortion of the flat-top shape was clearly observed [26]. The turbulence effects of the flat-top signature resembled that of the normal N-shaped signature.…”

Section: Introductionmentioning

confidence: 79%

Turbulent jet interaction with a long rise-time pressure signature

2016

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Abstract:A sonic boom signature with a long rise time has the ability to reduce the sonic boom, but it does not necessarily minimize the sonic boom at the ground level because of the real atmospheric turbulence. In this study, an effect of the turbulence on a long rise-time pressure signature was experimentally investigated in a ballistic range facility. To compare the effects of the turbulence on the long and short rise-time pressure signatures, a cone-cylinder projectile that simultaneously produces these pressure signatures was designed. The pressure waves interacted with a turbulent field generated by a circular nozzle. The turbulence effects were evaluated using flow diagnostic techniques: high-speed schlieren photography, a point-diffraction interferometer, and a pressure measurement. In spite of the fact that the long and short rise-time pressure signatures simultaneously travel through the turbulent field, the turbulence effects do not give the same contribution to these overpressures. Regarding the long risetime pressure signature, the overpressure fluctuation due to the turbulence interaction is almost uniform, and a standard deviation 1.5 times greater than that of the no-turbulence case is observed. By contrast, a short rise-time pressure signature which passed through the same turbulent field is strongly affected by the turbulence. A standard deviation increases by a factor of 14 because of the turbulence interaction. Additionally, there is a non-correlation between the overpressure fluctuations of the long and short rise-time pressure signatures. These results deduce that the length of the rise time is important to the turbulence effects such as the shock focusing/diffracting.

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Section: Introductionmentioning

confidence: 79%

Turbulent jet interaction with a long rise-time pressure signature

2016

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“…To illustrate their accuracy properties, the two sonic boom prediction methods outlined above are applied here to the prediction of the ground signatures of two configurations of the F5 fighter aircraft: (a) an original type E configuration (F5-E), and (b) a configuration with a reshaped nose section designed specifically to generate a low boom with a flattop ground signature (Pawlowski et al, 2004;Plotkin et al, 2004). In the following, the modified configuration is referred to as the SSBD -that is, the Shaped Sonic Boom Demonstrator.…”

Section: Application To the F5 Fighter Aircraftmentioning

confidence: 99%

Sonic boom mitigation via shape optimization using an adjoint method and application to a supersonic fighter aircraft

Maute

Farhat

Argrow

et al. 2008

TECM

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This paper describes a computational method for the analysis and mitigation via shape optimization of the sonic boom associated with supersonic flight. The method combines a CFD approach for determining the near-field pressure field and an acoustic scheme for predicting the initial shock pressure rise at the ground. Two venues are considered for computing the ground signature. The performance of both approaches is evaluated using flight test data of two different configurations of an F5 fighter aircraft.

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“…9 This breakthrough in low boom research proved that the boom signature of a supersonic aircraft could be controlled using careful shaping of the vehicle.…”

Section: Sonic Boom Suppression Technologiesmentioning

confidence: 99%