Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 6 of 6 for “"tonal and broadband noise"”.
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Active Minimization of Acoustic Energy Density to Attenuate Radiated Noise from a Diesel Generator
The focus of this thesis was to use active noise control (ANC) to globally minimize the tonal and broadband noise radiating from a diesel generator enclosure. The major goal of this research was to show that minimizing the noise within the enclosure can lead to an overall sound pressure level (SPL) …
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Low Frequency Noise Reduction Using Novel Poro-Elastic Acoustic Metamaterials
Low frequency noise is a common problem in aircraft and launch vehicles. New technologies must be investigated to reduce this noise while contributing minimal weight to the structure. This thesis investigates passive and active control methods to improve low frequency sound absorption and …
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Propeller Noise Prediction of an Urban Air Mobility Vehicle in Urban Environment
… environments where wake interactions, gust and turbulence significantly affect both performance and noise generation. Understanding these mechanisms is critical for developing quieter and more efficient eVTOL systems that meet future community noise and certification requirements. This …
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Bio-Inspired Axial Fan Design, 3D Printing Fabrication and Characterization for Noise and Flow Performance Optimization
Noise pollution from mechanical ventilation systems is an increasingly critical issue in the context of global energy transition, post-pandemic air quality requirements, and stringent environmental acoustic regulations. In this context, axial-flow fans represent a key technological component, …
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Prediction & Active Control of Multi-Rotor Noise
… developments have been made in designing and implementation of Advanced Air Mobility Vehicles (AAMV). However, wider applications in urban areas require addressing several challenges, such as safety and quietness. These vehicles differ from conventional helicopter in that they operate at a …
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Aerodynamic and Acoustic Modeling for eVTOL Rotor Noise Prediction
<p>This thesis presents the development and validation of a methodology for predicting total acoustic emissions from a one-fifth scale electric vertical takeoff and landing (eVTOL) rotor in both hover and edgewise flight conditions. The approach couples sectional two-dimensional Reynolds-Averaged …