Deflector shape impact on aero-acoustic noise generation and propagation

[EN] The acoustic pressure level generated during lift-off and the associated vibrations can significantly affect the payload of a launch vehicle. Optimizing the plume deflector is one of the most effective methods to reduce this noise. Considering the Vega launcher as a case of study, different def...

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Detalhes bibliográficos
Autores: Escartí-Guillem, Mara Salut, Hoyas, Sergio|||0000-0002-8458-7288, García-Raffi, L. M.|||0000-0003-3985-8453
Tipo de documento: artigo
Data de publicação:2023
País:España
Recursos:Universitat Politècnica de València (UPV)
Repositório:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
Idioma:inglês
OAI Identifier:oai:riunet.upv.es:10251/204519
Acesso em linha:https://riunet.upv.es/handle/10251/204519
Access Level:Acceso aberto
Palavra-chave:Launch noise
Prediction
CFD
Deflector shape
INGENIERIA AEROESPACIAL
MATEMATICA APLICADA
09.- Desarrollar infraestructuras resilientes, promover la industrialización inclusiva y sostenible, y fomentar la innovación
Descrição
Resumo:[EN] The acoustic pressure level generated during lift-off and the associated vibrations can significantly affect the payload of a launch vehicle. Optimizing the plume deflector is one of the most effective methods to reduce this noise. Considering the Vega launcher as a case of study, different deflectors are studied: flat, inclined at 30 degrees, and wedge. The approach followed is to use the unsteady Navier-Stokes equations to solve both the noise generation and the propagation. First, it has been observed that the blast wave, due to the ignition overpressure, is independent of the deflector geometry. However, the predominant acoustic waves are due to the impact of the jet with the deflectors. The analysis has shown that the flat deflector generates more shock waves and propagates the acoustic waves equally in all directions so that more acoustic loads reach the fairing. The inclined deflector causes a plate shock and intermediate tail shocks and redirects the flow towards one side of the launcher. Finally, the wedge deflector generates a detached shock wave with a higher pressure increase than the inclined deflector. However, as the flow is redirected towards the two sides, a lower OASPL reaches the fairing. In the same way, the pressure distribution over the fairing surface has shown that the wedge deflector is acoustically more efficient for this case of study. The acoustic effectiveness of deflectors has been demonstrated compared to the case without a deflector. Therefore, deflectors are advised to be included on the launch platform to improve payload comfort and reliability on the launchers.