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Dr. Mgr. Petr Koníček

Všechny publikace

Analysis of nonlinear standing waves in two coupled acoustic resonators

  • DOI: 10.1109/ULTSYM.2011.0422
  • Odkaz: https://doi.org/10.1109/ULTSYM.2011.0422
  • Pracoviště: Katedra fyziky
  • Anotace:
    The paper deals with description of nonlinear standing waves in acoustic resonators that are coupled mechanically by means of an elastically mounted wall which is implemented between the resonators. The coupling represents a linear oscillators. For the purpose of the behavior description of the nonlinear acoustic fields, the system of three model equations were derived. Two of them are the modified inhomogeneous Burgers equations and the third model equation is the oscillator's equation of motion. The investigated resonant system is excited by the harmonically vibrating pistons. The system of model equations was solved numerically in the frequency domain. The whole system obtains many parameters which can be changed. With help of these parameters we can adjust various configurations of the resonant system. The configurations, which offer interesting results, were studied. One of the configurations ensures that the resonant system behaves as a frequency convertor. Other selected configuration causes suppression of higher harmonic components in the one of the resonators.

Self-demodulation effects in nonlinear focused beams

  • DOI: 10.1109/ULTSYM.2011.0420
  • Odkaz: https://doi.org/10.1109/ULTSYM.2011.0420
  • Pracoviště: Katedra fyziky
  • Anotace:
    In this work, spatial distributions of acoustic pressure of the nonlinear focused sound beams are presented. Focused acoustic beams of periodic waves with an initially Gaussian amplitude distribution are considered. The numerical algorithm is based on the numerical solution of the nonlinear parabolic Khokhlov-Zabololotskaya-Kuznetsov (KZK) equation. The presented model enables to study the process of nonlinear generation of a low-frequency signal by the amplitude modulated high-frequency carrier wave.

Approximate Description of Finite-Amplitude Acoustical Waves in the Air-Filled Resonator

  • Pracoviště: Katedra fyziky
  • Anotace:
    The main goal of this paper is the description of the properties of the nonlinear standing waves generated by a vibrating boundary in the air-filled acoustical resonator. The nonlinear oscillations of gas in the hard-walled resonator having one closed end and the other periodically oscillating are analysed in this work. All phenomena leading to a progressive distortion of the wave are supposed to be weak. The analytic approach to finite-amplitude standing waves in a resonator of a constant diameter is used, based on the inhomogeneous Burgers equation with a discrepancy. In this paper we present the method of approximate solution of this equation in the stationary state.

Control of Nonlinear Standing Waves in Acoustic Resonators

  • Pracoviště: Katedra fyziky
  • Anotace:
    Though there are a number of methods which enable to control acoustic fields in resonators, this paper is focused on possibilities that offer the use of amplitude-modulated primary waves. This method makes possible to control energy transfer among harmonics and thus to form the acoustic field inside resonators. Better efficiency is achieved by a combination of the standard methods of influencing acoustic fields such as the method of acoustic resonance macrosonic synthesis, induced dispersion, selected absorption etc. The presented method of acoustic field control enables to suppress the generation of higher harmonics and thus suppress the nonlinear saturation effect. At the same time it offers new possibilities for excitation of nonlinear standing acoustic waves which are based on piezoelectric transducers.

High-Amplitude Standing Waves Between Collateral Discs

  • Pracoviště: Katedra fyziky
  • Anotace:
    The paper is concerned with study of behaviour of high-amplitude standing acoustic waves between two collateral discs whose dimensions are comparable with the wavelength. The work is motivated by research of possibilities of acousto-optical imaging in gases. Firstly, the system was numerically modeled in linear approximation using the Finite Elements Method in order to assess its Q-factor and resonant frequencies for different discs' radius-wavelength ratios. An approximate formula was found for calculation of resonance frequency for given geometry. Secondly, high-amplitude waveforms and generation of higher harmonics was studied using time-domain numerical integration of Navier-Stokes equations. It was observed that typical shock-wave does not develop in spite of considerable amplitudes of acoustic pressure that is caused by irregular distribution of resonant frequencies for individual modes.

Nonlinear acoustical waves in the air-filled resonator

  • DOI: 10.1109/ULTSYM.2009.5441693
  • Odkaz: https://doi.org/10.1109/ULTSYM.2009.5441693
  • Pracoviště: Katedra fyziky
  • Anotace:
    The main objective of this paper is the description of the properties of the nonlinear standing waves generated by a vibrating boundary in the acoustical resonator. The nonlinear oscillations of gas in the hard-walled air-filled resonator having one closed end and the other periodically oscillating are analyzed in this work.

Numerical simulation of parametric field patterns of ultrasonic transducer arrays

  • DOI: 10.1109/ULTSYM.2009.5441905
  • Odkaz: https://doi.org/10.1109/ULTSYM.2009.5441905
  • Pracoviště: Katedra fyziky
  • Anotace:
    The paper is concerned with numerical modeling of planar 2D ultrasonic transducer arrays for highly directional transmission of audio-frequency sound in air. The influences of the transducers arrangement in array is studied with respect to primary and secondary acoustic field patterns.

Parametric excitation of nonlinear standing waves in acoustic resonator

  • DOI: 10.1109/ULTSYM.2009.5441646
  • Odkaz: https://doi.org/10.1109/ULTSYM.2009.5441646
  • Pracoviště: Katedra fyziky
  • Anotace:
    The paper deals with parametric excitation of nonlinear standing waves in acoustic resonators. The used method is based on a parametric acoustic piston source which radiates an amplitude modulated ultrasonic waves. When a frequency of the demodulated wave is equal to some lower eigen-frequency of the resonator it is possible to excite nonlinear standing waves with its help. On the basis of theoretical investigation it was found that the presented method for generation of intensive acoustic fields inside the resonators is applicable.

Adaptive algorithm for active control of high-amplitude acoustic field in resonator

  • DOI: 10.1063/1.2956310
  • Odkaz: https://doi.org/10.1063/1.2956310
  • Pracoviště: Katedra fyziky
  • Anotace:
    This work is concerned with suppression of nonlinear effects in piston-driven acoustic resonators by means of two-frequency driving technique. An iterative adaptive algorithm is proposed to calculate parameters of the driving signal in order that amplitude of the second harmonics of the acoustic pressure is minimized. Functionality of the algorithm is verified firstly by means of numerical model and secondly, it is used in real computer-controlled experiment. The numerical and experimental results show that the proposed algorithm can be successfully used for generation of high-amplitude shock-free acoustic field in resonators.

Analysis of nonlinear wave processes in an elastic resonator

  • Pracoviště: Katedra fyziky
  • Anotace:
    The paper deals with investigation of nonlinear wave processes in elastic tube resonators which are excited by a vibrating piston. For this purpose we derived the modified inhomogeneous Burgers. equation which enables to model nonlinear standing waves in the supposed resonators. The influence of the dispersion and selective absorption, which are induced by the elastic wall, was investigated on the basis of the derived model equation. It was shown how the choice of the source frequency and amplitude can control an evolution of finite amplitude standing waves. Due to existence of dispersion we studied possibilities of subharmonic generation in the elastic resonator.

Finite amplitude standing waves in the cavity of the acoustical resonator

  • DOI: 10.1063/1.2956282
  • Odkaz: https://doi.org/10.1063/1.2956282
  • Pracoviště: Katedra fyziky
  • Anotace:
    This paper deals with the description of the forced vibrations of air in an acoustic resonator having one closed end and the other periodically oscillating. Acoustic field in the cavity of the acoustical resonator is described as a sum of counter propagating waves with no cross-interaction. Effects of nonlinearity, absorption and detuning are taken into account. The distortions of traveling waves within the resonator length are assumed to be small, the Mach number for the moving boundary and the difference between one of the resonant frequencies and the fundamental frequency of the driving motion of the piston are also assumed to be small. The novel approximate steady state solution of the model equation using matching in the case of small dissipation is presented in this paper. The nonlinear frequency response of the resonator is calculated here for steady state oscillations for both inviscid and dissipative media. These calculations are based on the presented approximate solution.

Properties of the Nonlinear Standing Waves Generated by a Vibrating Boundary

  • Autoři: Dr. Mgr. Petr Koníček,
  • Publikace: 19th International Congress on Acoustics. Madrid: Sociedad Espaňola de Acústica, 2007. pp. 1-5. ISBN 84-87985-12-2.
  • Rok: 2007
  • Pracoviště: Katedra fyziky
  • Anotace:
    The main objective of this paper is the description of the properties of the nonlinear standing waves generated by a vibrating boundary in the acoustical resonator. The analytic approach to finite-amplitude standing waves in a resonator of a constant diameter is used, based on the inhomogeneous Burgers equation with a discrepancy. Novel approximate solution of the inhomogeneous Burgers equation in stationary state regime is shown in this work.

Nonlinear acoustic threewave interactions in elastic waveguides and resonators

  • Pracoviště: Katedra fyziky
  • Anotace:
    The paper is focused on the problems concerning threewave nonlinear acoustic interactions in elastic resonators or tubes. Study of nonlinear threewave interactions enables to understand an influence of elastic wall dispersion on generation of higher harmonics.

Nonlinear oscillations of gas in acoustical resonator

  • Pracoviště: Katedra fyziky
  • Anotace:
    The main objective of this paper is the theoretical description of the suppression of the nonlinear attenuation and thus increasing of the quality factor of the given resonator. The decribed method is based on the active suppression of the second harmonic component of the sound. The resonator is driven by a piston whose motions is characterized by two superposed sinusoidal motions. The frequency of the first motion f is equal to the resonator eigenfrequency and the frequency of the second one is 2f and its the phase shift is 180 degrees.

Analýza nelineárních akustických interakcí

  • Pracoviště: Katedra fyziky
  • Anotace:
    Práce je věnována problematice efektivity nelineárních akustických interakcí. Zejména je v tomto ohledu studován vliv interakčního úhlu a dsperze na efektivitu nelineárních interakcí.

Multifrekvenčně buzený akustický rezonátor

  • Autoři: Dr. Mgr. Petr Koníček,
  • Publikace: 70. akustický seminář. Praha: Česká akustická společnost, 2005. pp. 69-76. ISBN 80-01-03253-1.
  • Rok: 2005
  • Pracoviště: Katedra fyziky
  • Anotace:
    Práce se zabývá problematikou multifrekvenčně buzeného akustického rezonátoru.

Nelineární zvukové vlny v kapalinách obsahujících bubliny plynu

  • Pracoviště: Katedra fyziky
  • Anotace:
    Práce se zabývá modelovými rovnicemi nelineární akustiky pro popis šíření zvukových vln v kapalinách obsahujících bubliny plynu. Ve druhém přiblížení je odvozena Kuzněcovova a Kortewegova-de Vriesova-Burgersova vlnová rovnice.

Active Harmonic Suppression in the Nonlinear Acoustical Resonator

Aktivní potlačování harmonických ve válcovém akustickém rezonátoru

Approximate analytical solution of inhomogeneous Burgers equation

Asymptotic solution of the ihomogeneous Burgers equation

Description of quasi-plane nonlinear standing waves in cylindrical resonators

Finite-Amplitude Standing Waves in Cylindrical and Spherical Acoustic Resonators

  • Pracoviště: Katedra fyziky
  • Anotace:
    The work is concerned with study of high-amplitude acoustic resonance in field of spherical and cylindrical waves. Numerical results show excitation of high-amplitude shock-free acoustic fields and resonance-frequency shifts depending on amplitude of the field.

Nonlinear Standing Waves in Elastic Resonators

Active Control of Harmonics in Nonlinear Acoustic Resonators

Asymptotic solutions of the inhomogeneous Burgers equation

Asymptotická řešení nehogenní Burgersovy rovnice

Nonlinear Standing Waves in Acoustic Resonators with Arbitrary Reflection Coefficients at Their Walls

Propagation of Quasi-Plane Nonlinear Waves in Tubes

Selektivní potlačení harmonických v akustickém rezontoru

Suppression of Harmonics by Selective Absorbers in the Resonators

Temperature Effects in Acoustic Resonators

Autodemodulation of Nonlinear Sound Waves

Influences of a Boundary Layer on Nonlinear Standing Waves in Closed Cylindrical Resonators

Modelling of nonlinear standing sound waves in czlindrical resonators

Nelineární stojaté vlny v akustických rezonátorech konstantního kruhového průřezu - Experiment

Nonlinear Standing Waves in an Acoustical Resonator with the Longitudinal Mean Temperature Distribution

Propagation of quasiplane nonlinear waves in tubes and the approximate solutions of the generalized Burgers equation

Rozložení akustické rychlosti ve válcovém rezonátoru

Solution of the Burgers Equation in the Time Domain

Spatial Evolution of Velocity in the Cylindrical Resonator

Využití nehomogenní Burgersovy rovnice pro popis nelineárních stojatých vln v rezonátorech kruhového průřezu

Analýza v časové oblasti - přechodové jevy v akustických rezonátorech

Autodemodulace nelineárních zvukových svazků

Computer Model of Nonlinear Waves Propagating in Duct

  • Autoři: Dr. Mgr. Petr Koníček,
  • Publikace: Proceedings of Workshop 2001. Praha: České vysoké učení technické v Praze, 2001. pp. 122-123. ISBN 80-01-02335-4.
  • Rok: 2001

Modely šíření nelineárních akustických vln ve zvukovodech s osovou symetrií

  • Autoři: Křemen, P., Dr. Mgr. Petr Koníček,
  • Publikace: 62. akustický seminář. Praha: Česká akustická společnost, 2001. pp. 33-36. ISBN 80-01-02372-9.
  • Rok: 2001

Nonlinear Effects in the Sound Field of the Circular Piston

Nonlinear standing waves in resonators of arbitrary axisymetric shape

Nonlinear Ultrasound Diagnostics

  • Autoři: Dr. Mgr. Petr Koníček,
  • Publikace: Proceedings of Workshop 2001. Praha: České vysoké učení technické v Praze, 2001. pp. 124-125. ISBN 80-01-02335-4.
  • Rok: 2001

Numerical Solution of Nonlinear Wave Model Equations

  • Autoři: Křemen, P., Dr. Mgr. Petr Koníček,
  • Publikace: Poster 2001. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 2001. pp. NS25.
  • Rok: 2001

Popis šíření nelineárních kvazirovinných vln ve zvukovodech kruhového průřezu

Prostředky numerického řešení jednorozměrných modelových rovnic v nelineární akustice

Study of finite-amplitude acoustic waves in resonators

The Transient Phenomena in Acoustical Resonators

Vliv mezní vrstvy v akustických rezonátorech

Využití Coleovy-Hopfovy transformace při numerickém řešení Burgersových rovnic v časové oblasti

Využití nelineárních zvukových interakcí pro distribuci zvuku

Využití parametrického pole ke generaci slyšitelného zvuku

Active Control Applied to Fan Noise in a Duct

  • Pracoviště: Katedra fyziky
  • Anotace:
    Dvoukanálový ANC systém v potrubí

Comparison of Acoustic Feedback Compensation Methods

  • Pracoviště: Katedra fyziky
  • Anotace:
    Článek srovnává čtyři metody kompenzace akustické zpětné vazby.

Finite-Amplitude Acoustic Waves in a Liquid-Filled Tube

Finite-Amplitude Acoustic Waves in Liquid-Filled Resonators

Popis nelineárních stojatých vln ve válcovém rezonátoru pomocí Burgersových rovnic

Rezonátory kruhového průřezu s vysokým činitelem jakosti Q pro nelineární stojaté vlny

Šíření akustických vln konečné amplitudy v potrubí

Study of the u-LMS Based ANC System

Suppression of Nonlinear Effects in Acoustic Resonators

Adaptive Feed Forward Control with Active Identification

  • Pracoviště: Katedra fyziky
  • Anotace:
    Adaptivní řízení v systému feed-forward s aktivní identifikací

Adaptive feed-forward control of broadband noise

  • Pracoviště: Katedra fyziky
  • Anotace:
    Článek se zabývá adaptivním algoritmem pro ANC.

Application of methods of acoustic feedback compensation

  • Pracoviště: Katedra fyziky
  • Anotace:
    Článek srovnává metody kompenzace akustické zpětné vazby

Experiences with Attenuation of Low-frequency Noise in Duct

  • Pracoviště: Katedra fyziky
  • Anotace:
    Experimentální výsledky při použití ANC

Fan Noise Attenuation using Feed Forward Control

  • Pracoviště: Katedra fyziky
  • Anotace:
    Snizovani hluku ventilatoru v pomoci systemu feed-forward

Kompenzace zpětné vazby v ANC systému pomocí Swinbanksova zdroje

  • Pracoviště: Katedra fyziky
  • Anotace:
    Kompenzace zpětné vazby pomocí zdroje vyzařujícího v jednom směru

Practical approach to ANC of fan noise with feedback compensation

  • Pracoviště: Katedra fyziky
  • Anotace:
    Realizace ANC se Swinbanksovým zdrojem

Active Attenuation of Fan Noise in an Air-conditioning Duct

Active Noise Control in a Duct by Adaptive Feed-forward Control

  • Pracoviště: Katedra fyziky
  • Anotace:
    Článek popisuje ANC systém v potrubí

Application of x-LMS Algorithm for Fan Noise Reduction

  • Pracoviště: Katedra fyziky
  • Anotace:
    Použití algoritmu x-LMS pro snižování hluku ventilátoru

Fan Noise Attenuation by Single Channel LMS System

  • Pracoviště: Katedra fyziky
  • Anotace:
    Snižování hluku ventilátorů s užitím jednokanálové soustavy LMS

Praktická realizace jednokanálového ANC s kompenzací akustické zpětné vazby

  • Pracoviště: Katedra fyziky
  • Anotace:
    Článek se zabývá realizací jednokanálového ANC s kompenzací akustické zpětné vazby.

Active Control of Sound in Wave-Guide

  • Pracoviště: Katedra fyziky
  • Anotace:
    Aktivní snižování hluku ve zvukovodu

An Experimental Study of Active Control in a Duct

Basic Study of ANC in an Acoustic Wave-Guide

Implementation of In-duct Active Control

Narrow Band Implementation of ANC in Duct

  • Pracoviště: Katedra fyziky
  • Anotace:
    Úzkopásmová realizace ANC v potrubí

Zkušenosti s aktivním snižováním hluku v potrubí

Noise of Automobile Alternator

  • Pracoviště: Katedra fyziky
  • Anotace:
    Clanek se zabyva merenim a potlacovanim elektromagnetickeho hluku alternatoru.

Větrné elektrárny a hluk

  • Pracoviště: Katedra fyziky
  • Anotace:
    Clanek se zabyva principy generovani a mereni hluku vetrnych elektraren.

Větrné elektrárny a měření jejich hluku

  • Pracoviště: Katedra fyziky
  • Anotace:
    Clanek se zabyva metodou mereni hluku vetrnych elektraren pomoci merici desky.

Aerodynamic Noise in Ducts. Preliminary Study for the ANC

Baffle Plate Method for Measurement of Noise Produced by Wind Turbines

Měření hluku větrných elektráren mikrofonem zapuštěným do pevné desky

Dynamic Model of the Rail Plasma Accelerator

  • Autoři: Maloch, J., Dr. Mgr. Petr Koníček,
  • Publikace: CTU Seminar 94. Praha: České vysoké učení technické v Praze, 1994, pp. 85-86.
  • Rok: 1994

Influence of Ablation to Projectile Velocity in the Rail Plasma Accelerator

  • Autoři: Dr. Mgr. Petr Koníček, Staněk, Z., Šablatura, J.
  • Publikace: Proceedings 16th Symposium on Plasma Physics and Technology. Praha: České vysoké učení technické v Praze, 1993. pp. 57.
  • Rok: 1993

Plasma Temperature in the Rail Plasma Accelerator

  • Autoři: Maloch, J., Dr. Mgr. Petr Koníček, Šablatura, J.
  • Publikace: Workshop 93. Praha: České vysoké učení technické v Praze, 1993. pp. 91-92.
  • Rok: 1993

The Temperature and Pressure in the Plasma Parallel Plate Accelerator

  • Autoři: Dr. Mgr. Petr Koníček, Staněk, Z.
  • Publikace: Czechoslovak Journal of Physics. 1993, 43(6), 647-660. ISSN 0011-4626.
  • Rok: 1993

Za stránku zodpovídá: Ing. Mgr. Radovan Suk