Design of a silicon photonic microphone

In a world increasingly dominated by technological advancements, the demand for high-quality microphones has never been more present. Seamless speech recognition and the development of userfriendly hearing aids remain significant challenges. State-of-the-art micro-electromechanical system (MEMS) microphones are reaching their bottlenecks in...

Acoustic Noise Analysis and Reduction of Electric Motors: Using Numerical Electromagnetic, Mechanic and Acoustic Finite Element Method Noise Modelling

In this thesis, the acoustic noise emitted by a small electric outrunner motor, such as the ones commonly used in unmanned areal vehicles, is analyzed using a multiphysics simulation based on the finite element method. The simulation covers the electromagnetic, mechanical and acoustic domain. The electromagnetic simulation is performed in the 2D...

Aero-acoustic response of an acoustic liner

In this thesis, the resistance of a single degree of freedom liner is investigated experimentally. Semi-empirical resistance modelling fails at higher Mach numbers (M₀>0.3) and sound pressure levels (SPL>130dB), and experimental work is missing in these conditions. An experiment combining in-situ impedance measurements and phase...

Acoustic Noise Analysis of Interior Permanent Magnet Synchronous Machine for Electric Vehicle Application

This paper analyses the electromagnetic resulted acoustic noise of an interior permanent magnet synchronous machine (IPMSM). The influences of electromagnetic nonlinearity, pulse-width-modulation (PWM) and motor frame on the acoustic noise are considered. A finite element model is used to extract the look up tables (LUTs) of flux linkage and air...

Prediction of acoustic noise and vibration of a 24/16 traction switched reluctance machine

This study presents a numerical modelling approach for the prediction of vibration and acoustic noise for a 24/16 traction switched reluctance machine (SRM). The numerical modelling includes the simulation of electromagnetic force in JMAG, the calculation of natural frequencies and the simulation of vibration and acoustic noise in ACTRAN....

Modeling and Analysis of Electric Motors: State-of-the-Art Review

This paper presents a comprehensive state-of-the-art review of the modeling and analysis methods for the multidisciplinary design of electric motors for various applications including vehicular power and propulsion systems and electrified powertrains. It covers the important aspects of different engineering domains, such as dynamic modeling,...

Evaluation of the Potential Radar Cross-Section & Experimental Aero-Acoustic Noise Merits of the GA-ASI MQ-9 Reaper by Applying Flap Morphing

Defence institutions and military aircraft manufacturers are increasingly exploring the ways to im- prove stealth in new aircraft designs. Design for low observability, more specifically for low Radar Cross-Section is the fundamental design aspect during design of a new military aerial vehicle. Acoustic stealth is also an important...

Three-dimensional evolution of flow structures in transitional circular and chevron jets

The three-dimensional behavior of flow transition in circular and 6-chevron jets at Re?=?5000 is investigated with experiments conducted on a free water jet by time-resolved tomographic particle image velocimetry. The emphasis is on the unsteady organization of coherent flow structures, which play a role in the generation of acoustic noise....

An evaluation of objective measures for intelligibility prediction of time-frequency weighted noisy speech

Existing objective speech-intelligibility measures are suitable for several types of degradation, however, it turns out that they are less appropriate in cases where noisy speech is processed by a time-frequency weighting. To this end, an extensive evaluation is presented of objective measure for intelligibility prediction of noisy speech...

An evaluation of objective measures for intelligibility prediction of time-frequency weighted noisy speech

Existing objective speech-intelligibility measures are suitable for several types of degradation, however, it turns out that they are less appropriate in cases where noisy speech is processed by a time-frequency weighting. To this end, an extensive evaluation is presented of objective measure for intelligibility prediction of noisy speech...

A study on the application of two different acoustic analogies to experimental PIV data

The aim of the present study is to compare two different acoustic analogies applied to time-resolved particle image velocimetry (PIV) data for the prediction of the acoustic far-field generated by the flow over a rectangular cavity. We consider the model problem of sound radiating from an open, two-dimensional, shallow cavity with an aspect...

A measurement model for general noise reaction in response to aircraft noise

In this paper a measurement model for general noise reaction (GNR) in response to aircraft noise is developed to assess the performance of aircraft noise annoyance and a direct measure of general reaction as indicators of this concept. For this purpose GNR is conceptualized as a superordinate latent construct underlying particular manifestations...

Investigation of higher spanwise Helmholtz resonance modes in slender covered cavities

Cavity aeroacoustic noise is relevant for aerospace and automotive industries and widely investigated since the 1950s. Most investigations so far consider cavities where opening length and width are of similar scale. The present investigation focuses on a less investigated setup, namely cavities that resemble the door gaps of automobiles. These...

Effect of room absorption on human vocal output in multitalker situations

People increase their vocal output in noisy environments. This is known as the Lombard effect. The aim of the present study was to measure the effect as a function of the absorption coefficient. The noise source was generated by using other talkers in the room. A-weighted sound levels were measured in a 108?m3 test room. The number of talkers...