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Vibrace vyvolané proudem tekutiny 2008
Zolotarev, Igor ; Horáček, Jaromír
Flow-induced vibrations and noise continue to cause problems in a wide range of engineering applications, ranging from mechanical and aerospace engineering, civil engineering and ship and offshore structures to power generation and chemical processing. These proceedings bring together 139 papers dealing with a variety of topics relating to flow-induced vibration and noise, such as:vortex-induced vibration, vibration of heat-exchanger tube bundles,progress in fluid-structure interaction theory and CFD simulations, flow-sound interaction, biomechanics of voice and hearing, thermo-acoustic instabilities, vibration of hydraulic structures, gates, turbomachines nad piping systems. The contents of this publication constitute a „mixture“ of investigations by those working on the mechanisms of vibration and means of their alleviation, and studies by those in industry who draw on the present state of knowledge of these mechanisms to avoid or solve flow induced vibratin and noise problems in industrial and other applications.
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Dynamic properties of some physical models of artificial vocal folds
Šidlof, Petr ; Veselý, Jan ; Horáček, Jaromír
The report presents results from measurements of acoustic and vibratory characteristics of six originally designed artificial vocal fold prototypes made of silicon rubber and based on various aeroelastic principles. During measurements, the dynamic subglottal pressure and output acoustic pressure were recorded. Spectral analysis of the signals was performed, and where the construction permitted, the vibrations were also observed by means of videostroboscopy. For two prototypes a shape and material optimization is possible with the aid of the mathematical models developed in IT AS CR.
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Simulace lidského hlasu s využitím MKP modelu vokálního traktu
Horáček, Jaromír ; Griffond-Boitier, F.
Finite element models of male vocal tract for Czech vowel /a/ are analyzed and used for numerical simulation of phonation. The models were designed from the MRI the subject during phonation. The acoustic signals for the vowel /a/ are simulated using the transient analysis. For excitation of the supraglottal spaces the intraglottal pressure or airflow rate generated by the aeroelastic model of vocal folds self-oscillations is used. The frequency and time response functions calculated near the lips and in front of the mouth are compared with acoustic measurements.
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Dynamic characteristics of the human vocal tract influenced by the cleft palate
Vampola, T. ; Horáček, Jaromír ; Bauma, V.
Finite element models of supraglottal tract for Czech vowels /a/ and /u/ are analyzed considering the cleft palate. Performed acoustic modal analysis is focused on investigation of the influence of the area of cleft palate on the formant frequencies F1-F3. The results for the vowel /a/ indicate, that after a small jump of the acoustic natural frequencies for a very small cleft the frequencies F1 and F2 are influence by increasing size the cleft only very slightly. The influence of the cleft on the phonation of the vowel /u/ is considerable higher.
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3-D FE model of the human vocal folds for dynamic computations
Vampola, T. ; Horáček, Jaromír
The article describes the design of a 3D finite element (FE) model of real human vocal folds in a defined phonation position. The model was developed from the CT images of the plaster casts obtained by a special procedure during experiments with the excised human larynges. The model is determined mainly for studies of dynamical stresses in the vocal fold tissue during vocal folds collisions.
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Dynamic properties of some physical models of artificial vocal folds
Šidlof, Petr ; Veselý, Jan ; Horáček, Jaromír
The paper presents results of measurements of acoustic and vibratory characteristics of several artificial vocal fold prototypes based on various principles. During measurements the dynamic subglottal pressure and output acoustic pressure were recorded. Spectral analysis of the signals was performed, and where the construction permitted, the vibrations were also observed by means of videostroboscopy. In some cases, a computer-modelling-based shape and material optimizations is possible with the aid of the mathematical models developed in IT AS CR.
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