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Supersonic Jet Excitation using Flapping Injection

Haukur Hafsteinsson (Institutionen för tillämpad mekanik, Strömningslära) ; Lars-Erik Eriksson (Institutionen för tillämpad mekanik, Strömningslära) ; Niklas Andersson (Institutionen för tillämpad mekanik, Strömningslära) ; Daniel Cuppoletti ; Ephraim Gutmark ; Erik Prisell
American Physical Society, Division of Fluid Dynamics 66th Annual Meeting, November 24–26, 2013 Pittsburgh, Pennsylvania (2013)
[Konferensbidrag, övrigt]

Supersonic jet noise reduction is important for high speed military aircraft. Lower acoustic levels would reduce structural fatigue leading to longer lifetime of the jet aircraft. It is not solely structural aspects which are of importance, health issues of the pilot and the airfield personnel are also very important, as high acoustic levels may result in severe hearing damage. It remains a major challenge to reduce the overall noise levels of the aircraft, where the supersonic exhaust is the main noise source for near ground operation. Fluidic injection into the supersonic jet at the nozzle exhaust has been shown as a promising method for noise reduction. It has been shown to speed up the mixing process of the main jet, hence reducing the kinetic energy level of the jet and the power of the total acoustic radiation. Furthermore, the interaction mechanism between the fluidic injection and the shock structure in the jet exhaust plays a crucial role in the total noise radia- tion. In this study, LES is used to investigate the change in flow structures of a supersonic (M=1.56) jet from a converging-diverging nozzle. Six fluidic actuators, evenly distributed around the nozzle exit, inject air in a radial direction towards the main flow axis with a total mass flow ratio of 3%. Steady injection is compared with flapping injection. With flapping injection turned on, the injection angle of each injector is varied sinusoidally in the nozzle exit plane and the variation is the same for all injectors. This fluid dynamics video is submitted to the APS DFD Gallery of Fluid Motion 2013 at the 66 the Annual Meeting of the American Physical Society, Division of Fluid Dynamics (24-26 November, Pittsburgh, PA, USA).

Nyckelord: Strömningsmekanik, Akustik, CFD



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Denna post skapades 2013-12-02. Senast ändrad 2014-10-27.
CPL Pubid: 188125

 

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Institutioner (Chalmers)

Institutionen för tillämpad mekanik, Strömningslära (2005-2017)

Ämnesområden

Transport
Hållbar utveckling
Strömningsmekanik och akustik

Chalmers infrastruktur

C3SE/SNIC (Chalmers Centre for Computational Science and Engineering)