Transmission Line Matrix (TLM) in Computational Mechanics

Cogan, Donard de; O’Connor, William; Pulko, S. H.

doi:10.1201/9780203022184

Cited by 22 publications

(52 citation statements)

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“…This is found by forming the The´venin equivalent network and solving for f (the potential at the node point) [4]. Equation (5) can be used at any discrete multiple (k) of Dt (time), to observe the potential existent on any node (x; y).…”

Section: Transmission Line Matrix Modellingmentioning

confidence: 99%

“…We will begin with an introduction to the TLM numerical method, indicating the procedure and formulation relevant to the current situation, a more formal and of greater depth introduction can be found in the relevant literature [3,4], this section will then continue to introduce two boundary conforming schemes, the first proposed by Mueller et al [5], and the second, a new technique attempting to limit the drawbacks of the Mueller et al approach, these will become useful in Section 4 where the TLM mesh will be moved to simulate the effect of a moving medium and hence boundary placement between nodes will be required. Before this is attempted some approaches to moving the source within a stationary mesh will be analysed in Section 3, indicating the errors obtained which we attempt to circumvent in Section 4.…”

Section: Introductionmentioning

confidence: 99%

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An investigation into time domain Doppler modelling using the TLM numerical method

Scott

Cogan

2007

Int J Numerical Modelling

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SUMMARYThe effects observed by a moving source and stationary receiver, or conversely stationary source and moving receiver are well known to physicists. The Doppler effect as it is commonly known is recognized as a perceived change in frequency of the incident signal upon the receiver, caused by the motion of either the source or receiver with respect to the stationary component, occurring in both electromagnetic (transverse) and acoustic (longitudinal) waves. This paper will primarily focus on the acoustic Doppler effect in the time domain, simulating a variety of scenarios using transmission line matrix (TLM) modelling in which the effect can be observed, proceeding to compare the accuracy of the various models generated. A new technique to allow arbitrary placement of boundaries of a TLM mesh will also be introduced and analysed allowing accurate placement of the moving walls within the simulation.

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Section: Transmission Line Matrix Modellingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An investigation into time domain Doppler modelling using the TLM numerical method

Scott

Cogan

2007

Int J Numerical Modelling

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“…En este trabajo, el modelo utilizado será el nodo 3D de derivación sin pérdidas, ya que tiene mucho éxito en la solución de los problemas acústicos. La relación entre los coeficientes de transmisión () y de reflexión () en las puertas de un nodo 3D de derivación sin pérdidas y la matriz de dispersión, que se indican a continuación, se derivan en (Cogan et al, 2006). La Eq.…”

Section: El Método De La Línea De Transmisión (Tlm)unclassified

Método de Línea de Transmisión aplicado a la Acústica del Tracto Vocal a través de un Modelo 3D Reconstruido

2012

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ResumenSe ha simulado la propagación acústica en el tracto vocal humano usando el Método de La Línea de Transmisión (TLM). Se construyeron mallas tridimensionales a partir de segmentaciones de imágenes de resonancia magnética. Inicialmente se construyen modelos simples de uno y dos tubos y luego se simula la misma señal en un modelo de tracto vocal humano cuya forma representa la producción de la vocal abierta /a/, simulando también la propagación de una señal glotal. Para el modelo del tracto vocal, las señales de voz generadas mediante las simulaciones fueron comparadas con muestras de voz del mismo sujeto a quien se extrajo la malla. Se propone un factor de compensación de la dispersión numérica dependiente de la topología para mejorar la determinación de los formantes. Se concluye que el factor de compensación mejora la eficacia y exactitud del método TLM. Palabras clave: Método de La Línea de Transmisión, Dispersión numérica, Producción de voz Transmission Line Method applied to vocal tract acoustics through a 3D reconstructed model AbstractThe acoustic propagation in the human vocal tract using the Transmission Line Matrix method (TLM) has been simulated. Tri-dimensional meshes are built from segmented magnetic resonance images. Initially, simple models of one and two tubes were constructed to then simulate the same signal in a human vocal tract model whose shape represents the production of the open vowel /a/, simulating at the same time a human glottal signal. For the vocal tract model, the voice signals generated by the simulations were compared with voice samples from the same subject from whom the mesh was extracted. A compensation factor for the topology-dependent numerical dispersion for improving formant determination is proposed. It is concluded that the proposed compensation factor improves the effectiveness and accuracy of the TLM method.

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“…Depending on the physical domain, waves can for instance consist of mechanical forces, electrical voltage or hydraulic pressure. A good overview of TLM is given by de Cogan et al [13]. The method originates from the method of bi-lateral delay lines [14] and from transmission line modelling [15].…”

Section: Distributed System Modellingmentioning

confidence: 99%

An explicit method for decoupled distributed solvers in an equation-based modelling language

Braun

Krus

2014

Proceedings of the 6th International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools

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The Modelica language offers an intuitive way to create object-oriented models. This makes it natural also to use an object-oriented solver, where each sub-model solves its own equations. Doing so is possible only if sub-models can be made independent from the rest of the model. One way to achieve this is to use distributed solvers by separating submodels with transmission line elements. This offers robust and predictable simulations, simplified model debugging and natural parallelism. It also makes it possible to use different time steps and solver algorithms in different parts of the model to achieve an optimal trade-off between performance and accuracy. The suggested method has been implemented in the Hopsan simulation environment. Different modelling techniques for taking advantage of the distributed solver approach are explained. Finally, three example models are used to demonstrate the method.

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Transmission Line Matrix (TLM) in Computational Mechanics

Cited by 22 publications

References 0 publications

An investigation into time domain Doppler modelling using the TLM numerical method

An investigation into time domain Doppler modelling using the TLM numerical method

Método de Línea de Transmisión aplicado a la Acústica del Tracto Vocal a través de un Modelo 3D Reconstruido

An explicit method for decoupled distributed solvers in an equation-based modelling language

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