Thermoacoustically controlled Helmholtz resonators

2013 ◽  
Vol 227 (11) ◽  
pp. 2563-2568
Author(s):  
Konstantin I Matveev
Keyword(s):  
Power Systems ◽  
Thermal Stratification ◽  
Sound Absorption ◽  
Element Model ◽  
Temperature Gradients ◽  
Acoustic Oscillations ◽  
Helmholtz Resonators ◽  
Lumped Element ◽  
Effects Of Temperature ◽  
Lumped Element Model

Helmholtz resonators and their modifications are commonly applied for suppressing unwanted sound, including acoustic oscillations in chambers of propulsion and power systems. Sound absorption characteristics of Helmholtz resonators can be enhanced and controlled with a use of thermal stratification in porous insets inside resonators. A simplified lumped-element model for thermoacoustically augmented Helmholtz resonators is developed in this article. Sample calculations illustrate effects of temperature gradients, porosity, positions of porous insets, and locations of resonators inside chambers.

scholarly journals A computationally efficient hybrid 2D–3D subwoofer model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ahmad H. Bokhari ◽  
Martin Berggren ◽  
Daniel Noreland ◽  
Eddie Wadbro
Keyword(s):  
Hybrid Model ◽  
3D Model ◽  
Element Model ◽  
Acoustic Properties ◽  
Computational Time ◽  
Average Response ◽  
Frequency Range ◽  
Computationally Efficient ◽  
Lumped Element ◽  
Lumped Element Model

AbstractA subwoofer generates the lowest frequency range in loudspeaker systems. Subwoofers are used in audio systems for live concerts, movie theatres, home theatres, gaming consoles, cars, etc. During the last decades, numerical simulations have emerged as a cost- and time-efficient complement to traditional experiments in the design process of different products. The aim of this study is to reduce the computational time of simulating the average response for a given subwoofer design. To this end, we propose a hybrid 2D–3D model that reduces the computational time significantly compared to a full 3D model. The hybrid model describes the interaction between different subwoofer components as interacting modules whose acoustic properties can partly be pre-computed. This allows us to efficiently compute the performance of different subwoofer design layouts. The results of the hybrid model are validated against both a lumped element model and a full 3D model over a frequency band of interest. The hybrid model is found to be both accurate and computationally efficient.

scholarly journals A general theory of glacier surges

2019 ◽  
Vol 65 (253) ◽  
pp. 701-716 ◽  
Author(s):  
D. I. Benn ◽  
A. C. Fowler ◽  
I. Hewitt ◽  
H. Sevestre
Keyword(s):  
General Theory ◽  
Frictional Heating ◽  
Element Model ◽  
Geothermal Heating ◽  
Lumped Element ◽  
Systems Model ◽  
Flow Speeds ◽  
Glacier Surges ◽  
Lumped Element Model ◽  
Polythermal Glacier

AbstractWe present the first general theory of glacier surging that includes both temperate and polythermal glacier surges, based on coupled mass and enthalpy budgets. Enthalpy (in the form of thermal energy and water) is gained at the glacier bed from geothermal heating plus frictional heating (expenditure of potential energy) as a consequence of ice flow. Enthalpy losses occur by conduction and loss of meltwater from the system. Because enthalpy directly impacts flow speeds, mass and enthalpy budgets must simultaneously balance if a glacier is to maintain a steady flow. If not, glaciers undergo out-of-phase mass and enthalpy cycles, manifest as quiescent and surge phases. We illustrate the theory using a lumped element model, which parameterizes key thermodynamic and hydrological processes, including surface-to-bed drainage and distributed and channelized drainage systems. Model output exhibits many of the observed characteristics of polythermal and temperate glacier surges, including the association of surging behaviour with particular combinations of climate (precipitation, temperature), geometry (length, slope) and bed properties (hydraulic conductivity). Enthalpy balance theory explains a broad spectrum of observed surging behaviour in a single framework, and offers an answer to the wider question of why the majority of glaciers do not surge.

scholarly journals Modeling the Biomechanical Influence of Epilaryngeal Stricture on the Vocal Folds: A Low-Dimensional Model of Vocal–Ventricular Fold Coupling

2014 ◽  
Vol 57 (2) ◽  
Author(s):  
Scott R. Moisik ◽  
John H. Esling
Keyword(s):  
Dynamical Behavior ◽  
Model Performance ◽  
Vocal Folds ◽  
Element Model ◽  
Dynamical Response ◽  
Lumped Element ◽  
Glottal Stop ◽  
Lumped Element Model ◽  
Low Dimensional ◽  
Ventricular Folds

Purpose Physiological and phonetic studies suggest that, at moderate levels of epilaryngeal stricture, the ventricular folds impinge upon the vocal folds and influence their dynamical behavior, which is thought to be responsible for constricted laryngeal sounds. In this work, the authors examine this hypothesis through biomechanical modeling. Method The dynamical response of a low-dimensional, lumped-element model of the vocal folds under the influence of vocal–ventricular fold coupling was evaluated. The model was assessed for F0 and cover-mass phase difference. Case studies of simulations of different constricted phonation types and of glottal stop illustrate various additional aspects of model performance. Results Simulated vocal–ventricular fold coupling lowers F0 and perturbs the mucosal wave. It also appears to reinforce irregular patterns of oscillation, and it can enhance laryngeal closure in glottal stop production. Conclusion The effects of simulated vocal–ventricular fold coupling are consistent with sounds, such as creaky voice, harsh voice, and glottal stop, that have been observed to involve epilaryngeal stricture and apparent contact between the vocal folds and ventricular folds. This supports the view that vocal–ventricular fold coupling is important in the vibratory dynamics of such sounds and, furthermore, suggests that these sounds may intrinsically require epilaryngeal stricture.

Evaluation of the Equivalent Lumped Element Parameters of Modified Microstrip Ring Resonator

2015 ◽  
Vol 735 ◽  
pp. 278-281
Author(s):  
Yi Lung Then ◽  
Kok Yeow You ◽  
Mohamad Ngasri Dimon ◽  
Wei Ying Lai
Keyword(s):  
Magnetic Field ◽  
Free Space ◽  
Ring Resonator ◽  
Element Model ◽  
Network Analyzer ◽  
Simulation Data ◽  
Lumped Element ◽  
Lumped Element Model ◽  
Microstrip Ring ◽  
Microstrip Ring Resonator

Microstrip ring resonator (MRR) sensor was modeled by simple equivalent lumped element circuits in free space based on simulation data obtained from Microwave Office (AWR) simulator and comparison was made with the measurements using the E5071C Network Analyzer. The calculated reflection coefficient, |G| and complex input impedanceZinusing lumped element model were compared with the measurements results. Both results showed well agreement with a little discrepancy, basically due to imperfect soldering. The MRR was designed to have operating frequencies between 0.5 GHz and 4.5 GHz. The maximum surrounding of magnetic field,Hϕis within 15 A/m in free space.

scholarly journals An all-Optical Photoacoustic Sensor for the Detection of Trace Gas

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3967
Author(s):  
Thomas Lauwers ◽  
Alain Glière ◽  
Skandar Basrour
Keyword(s):  
High Sensitivity ◽  
Element Model ◽  
Remote Detection ◽  
Trace Gas ◽  
Lumped Element ◽  
Highly Sensitive ◽  
Fabry Perot ◽  
All Optical ◽  
Lumped Element Model ◽  
Acoustic Sensitivity

A highly sensitive Fabry–Perot based transduction method is proposed as an all-optical alternative for the detection of trace gas by the photoacoustic spectroscopy technique. A lumped element model is firstly devised to help design the whole system and is successfully compared to finite element method simulations. The fabricated Fabry–Perot microphone consists in a hinged cantilever based diaphragm, processed by laser cutting, and directly assembled at the tip of an optical fiber. We find a high acoustic sensitivity of 630 mV/Pa and a state-of-the-art noise equivalent pressure, as low as ~   2   μ Pa / Hz at resonance. For photoacoustic trace gas detection, the Fabry–Perot microphone is further embedded in a cylindrical multipass cell and shows an ultimate detection limit of 15 ppb of NO in nitrogen. The proposed optical trace gas sensor offers the advantages of high sensitivity and easy assembling, as well as the possibility of remote detection.

Modeling and Optimizing Industrial Inkjet Printhead for Printable Electronics Fabrication

2015 ◽  
Vol 748 ◽  
pp. 15-19
Author(s):  
Lian Bo Ma ◽  
Mao Wei He ◽  
Kun Yuan Hu ◽  
Yun Long Zhu
Keyword(s):  
Experimental Studies ◽  
Element Model ◽  
Printable Electronics ◽  
Lumped Element ◽  
Drop On Demand ◽  
Printing Quality ◽  
Lumped Element Model ◽  
Driving Waveform ◽  
Nonlinear Behaviors ◽  
Inkjet Printhead

The most significant issues in printable electronics fabrication are the printing quality and efficiency delivered by drop-on-demand (DOD) industrial inkjet printhead. Aiming to characterize the nonlinear behaviors of piezoelectric inkjet printhead, the dynamic lumped element model (DLEM) is proposed to cast the original LEM into a time-varying and nonlinear fashion. At the same time , the PSO-based optimization for paramenters is incorporated in DLEM. Due to new characteristics, DLEM can accurately simulate the inkjet-printed nanosilver droplet formation process and effectively predicate optimal combinations of high-frequency driving waveform with high printing quality. From extensive experimental studies, the effectiveness and efficiency of the proposed DLEM is validated.

Lumped-element model of plasmonic solar cells

2018 ◽  
Vol 147 ◽  
pp. 39-43 ◽  
Author(s):  
Chang-Hyun Kim ◽  
Maria Seitanidou ◽  
Jong Woo Jin ◽  
Yvan Bonnassieux ◽  
Gilles Horowitz ◽  
...  
Keyword(s):  
Solar Cells ◽  
Element Model ◽  
Lumped Element ◽  
Lumped Element Model ◽  
Plasmonic Solar Cells

scholarly journals Simulation of the Readout Methods for Inductively Coupled High-Frequency Resonance Sensors

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 923
Author(s):  
Timo Salpavaara ◽  
Aleksi Hänninen ◽  
Jukka Lekkala ◽  
Minna Kellomäki
Keyword(s):  
High Frequency ◽  
Measurement Errors ◽  
Element Model ◽  
Measured Data ◽  
High Frequencies ◽  
Inductively Coupled ◽  
Lumped Element ◽  
Lumped Element Model ◽  
High Frequency Resonance ◽  
Reading Distance

The readout methods for inductively coupled resonance sensors were simulated using a lumped element model. The purpose of the study was to analyze the readout methods at high frequencies where the self-resonance of the reader coil is likely to interfere with the measurements. Furthermore, the changes in the reading distance cause measurement errors. This phenomenon was studied using simulation. In addition, an algorithm that compensates these errors was tested. The simulation results were in agreement with the test measurements. In addition, the tested error compensation improved the resonance frequency estimates calculated using the simulated and measured data.

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