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Master's Dissertation
DOI
https://doi.org/10.11606/D.3.2021.tde-03022022-143042
Document
Author
Full name
Rubens Cavalcante da Silva
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2021
Supervisor
Committee
Assi, Gustavo Roque da Silva (President)
Michima, Paula Suemy Arruda
Orselli, Reinaldo Marcondes
Title in English
Numerical evaluation on the effect of boss cap geometries on AUV propeller noise.
Keywords in English
AUV
Boss cap
Computational fluid dynamics
DES
Ffowcs Williams and Hawkings acoustic model
Hydroacoustics
Propeller
Abstract in English
This study numerically analyzed the underwater noise emitted from an autonomous underwater vehicle (AUV) high-skewed propeller (Mod5), considering five different boss cap geometries (elliptical and divergent) and using a commercial CFD code. The numerical model was developed by means of the Ffowcs Williams-Hawkings (FW-H) acoustic model, as well as the Dunn-Farassat-Padula formulation to subsonic rotating blades, coupled with a Detached Eddy Simulation (DES) turbulence model. The model was validated by comparing the numerical results with acoustics data from INSEAN E779A propeller. Numerical and experimental results showed that divergent boss caps presented lower values of propeller efficiency than the elliptical geometry. On the other hand, the most divergent geometry presented a slightly reducing of noise to certain frequency bands.
Title in Portuguese
Avaliação numérica do efeito de geometrias de caps no ruído do propulsor de um AUV.
Keywords in Portuguese
AUV
Bosso
DES
Dinâmica dos fluidos computacional
Hidroacústica
Modelo acústico de Ffowcs Williams-Hawkings
Propulsão
Abstract in Portuguese
Este trabalho realizou a análise numérica do ruído emitido por um propulsor de alto skew desenvolvido para operar em um veículo submarino autônomo (AUV), considerando-se 5 diferentes geometrias de bosso (elíptico e divergentes) e utilizando um código comercial de CFD. Foi utilizado o modelo acústico de Ffowcs WilliamsHawkings (FW-H), baseado na formulação de Dunn-Farassat-Padula para domínios rotativos subsônicos, acoplado ao modelo de turbulência DES (Detached Eddy Simulation). A validação do modelo foi feita através da comparação com dados disponíveis em literatura do propulsor INSEAN E779A. Os resultados numéricos de eficiência para cada geometria foram comparados com os obtidos experimentalmente em túnel de cavitação, onde se observou uma ligeira queda para os bossos divergentes se comparado com a geometria paradigma (bosso elíptico). Os resultados numéricos hidroacústicos mostraram que, para determinadas bandas de frequências, houve uma diminuição sensível do ruído para a geometria mais divergente de bosso.
 
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Publishing Date
2022-02-04
 
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