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Dr. Mgr. Petr Koníček

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Analysis of nonlinear standing waves in two coupled acoustic resonators

  • DOI: 10.1109/ULTSYM.2011.0422
  • Link: https://doi.org/10.1109/ULTSYM.2011.0422
  • Department: Department of Physics
  • Annotation:
    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
  • Link: https://doi.org/10.1109/ULTSYM.2011.0420
  • Department: Department of Physics
  • Annotation:
    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

  • Department: Department of Physics
  • Annotation:
    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

  • Department: Department of Physics
  • Annotation:
    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

  • Department: Department of Physics
  • Annotation:
    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
  • Link: https://doi.org/10.1109/ULTSYM.2009.5441693
  • Department: Department of Physics
  • Annotation:
    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
  • Link: https://doi.org/10.1109/ULTSYM.2009.5441905
  • Department: Department of Physics
  • Annotation:
    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
  • Link: https://doi.org/10.1109/ULTSYM.2009.5441646
  • Department: Department of Physics
  • Annotation:
    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
  • Link: https://doi.org/10.1063/1.2956310
  • Department: Department of Physics
  • Annotation:
    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

  • Department: Department of Physics
  • Annotation:
    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
  • Link: https://doi.org/10.1063/1.2956282
  • Department: Department of Physics
  • Annotation:
    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

  • Authors: Dr. Mgr. Petr Koníček,
  • Publication: 19th International Congress on Acoustics. Madrid: Sociedad Espaňola de Acústica, 2007. pp. 1-5. ISBN 84-87985-12-2.
  • Year: 2007
  • Department: Department of Physics
  • Annotation:
    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

  • Department: Department of Physics
  • Annotation:
    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

  • Department: Department of Physics
  • Annotation:
    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.

Acoustic Resonator with Multifrequency Driving

  • Authors: Dr. Mgr. Petr Koníček,
  • Publication: 70. akustický seminář. Praha: Česká akustická společnost, 2005. pp. 69-76. ISBN 80-01-03253-1.
  • Year: 2005
  • Department: Department of Physics
  • Annotation:
    The paper deals with problems of multifrequency-driven acoustic resonator

Analysis of nonlinear acoustic interactions

  • Department: Department of Physics
  • Annotation:
    The work deals with problems concerning efectivity of nonlinear acoustic interactions. The efectivity of nonlinear interactions is studied namely with respect to an interaction angle and dispersion.

Nonlinear Acoustic Waves in Fluids with Gas Bubbles

  • Department: Department of Physics
  • Annotation:
    The work is devoted to model equations of nonlinear acoustics for description of acoustic wave propagation in fluids containing gas-bubbles. The Kuznetsov's and Korteweg-de Vries model equations are derived in the second approximation.

Active Harmonic Suppression in the Nonlinear Acoustical Resonator

Active Suppression of Harmonics in a Cylindrical Acoustic Resonator

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

  • Department: Department of Physics
  • Annotation:
    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 Solution of Non-homogenous Burgers Equation

Asymptotic solutions of the inhomogeneous Burgers equation

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

Propagation of Quasi-Plane Nonlinear Waves in Tubes

Selective Suppression of Harmonics in Acoustic Resonators

Suppression of Harmonics by Selective Absorbers in the Resonators

Temperature Effects in Acoustic Resonators

Autodemodulation of Nonlinear Sound Waves

Distribution of acoustical velocity in an cylindrical resonator

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

Modelling of nonlinear standing sound waves in czlindrical resonators

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

Nonlinear standing waves in cylindrical acoustic resonators - Experimental results

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

Solution of the Burgers Equation in the Time Domain

Spatial Evolution of Velocity in the Cylindrical Resonator

Utilization of non-homogeneous Burgers equation for description of nonlinear standing waves in acoustical resonators

Analysis in time domain - the transient phenomena in acoustic resonators

Auto-demodulation of nonlinear sound beams

Computer Model of Nonlinear Waves Propagating in Duct

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

Description of nonlinear kvasiplane waves in cylindrical waveguides

Influence of the boundary layer in acoustical resonators

Means of the one-dimensional model equations solution in nonlinear acoustics

Models of nonlinear acoustic waves propagation in axisymatric waveguides

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

Nonlinear Effects in the Sound Field of the Circular Piston

Nonlinear standing waves in resonators of arbitrary axisymetric shape

Nonlinear Ultrasound Diagnostics

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

Numerical Solution of Nonlinear Wave Model Equations

  • Authors: Křemen, P., Dr. Mgr. Petr Koníček,
  • Publication: Poster 2001. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 2001. pp. NS25.
  • Year: 2001

Study of finite-amplitude acoustic waves in resonators

The Transient Phenomena in Acoustical Resonators

Using of the parametric array for audible sound generation

Utilization of Cole-Hopf transform for Burgers equation solution in time domain

Utilization of the nonlinear sound interactions for distribution of sound

Acoustic wave propagation

Active Control Applied to Fan Noise in a Duct

Comparison of Acoustic Feedback Compensation Methods

  • Department: Department of Physics
  • Annotation:
    Článek srovnává čtyři metody kompenzace akustické zpětné vazby.

Description of Nonlinear Standing Waves in Cylindrical Resonators Using Burgers Equations

Finite-Amplitude Acoustic Waves in a Liquid-Filled Tube

Finite-Amplitude Acoustic Waves in Liquid-Filled Resonators

Resonators of Circular Cross-Section with High Quality Factor for Nonlinear Standing Waves

Study of the u-LMS Based ANC System

Suppression of Nonlinear Effects in Acoustic Resonators

Adaptive Feed Forward Control with Active Identification

  • Department: Department of Physics
  • Annotation:
    Adaptivní řízení v systému feed-forward s aktivní identifikací

Adaptive feed-forward control of broadband noise

Application of methods of acoustic feedback compensation

  • Department: Department of Physics
  • Annotation:
    Článek srovnává metody kompenzace akustické zpětné vazby

Experiences with Attenuation of Low-frequency Noise in Duct

Fan Noise Attenuation using Feed Forward Control

  • Department: Department of Physics
  • Annotation:
    Snizovani hluku ventilatoru v pomoci systemu feed-forward

Feedback compensation by Swinbanks' source in ANC system

Practical approach to ANC of fan noise with feedback compensation

Active Attenuation of Fan Noise in an Air-conditioning Duct

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

Application of x-LMS Algorithm for Fan Noise Reduction

  • Department: Department of Physics
  • Annotation:
    Použití algoritmu x-LMS pro snižování hluku ventilátoru

Fan Noise Attenuation by Single Channel LMS System

  • Department: Department of Physics
  • Annotation:
    Snižování hluku ventilátorů s užitím jednokanálové soustavy LMS

Practical realization of single-channel ANC with compensation of acoustic feedback

  • Department: Department of Physics
  • Annotation:
    The paper deal with single channel feed-forward ANC system in a duct with feedback compensation.

Active Control of Sound in Wave-Guide

An Experimental Study of Active Control in a Duct

Basic Study of ANC in an Acoustic Wave-Guide

Experiences with Active Noise Control in Ducts

Implementation of In-duct Active Control

Narrow Band Implementation of ANC in Duct

Noise of Automobile Alternator

  • Department: Department of Physics
  • Annotation:
    Clanek se zabyva merenim a potlacovanim elektromagnetickeho hluku alternatoru.

Noise of wind-turbines

  • Department: Department of Physics
  • Annotation:
    The paper deals with generation and noise of wind-turbines.

Wind-turbines and measurement of noise

  • Department: Department of Physics
  • Annotation:
    The paper deals with baffle-plate method of wind-turbine noise measurement.

Aerodynamic Noise in Ducts. Preliminary Study for the ANC

Baffle Plate Method for Measurement of Noise Produced by Wind Turbines

Measurement of Wind Turbine Noise by Microphone Bafflet in a Hard Plate

Dynamic Model of the Rail Plasma Accelerator

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

Influence of Ablation to Projectile Velocity in the Rail Plasma Accelerator

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

Plasma Temperature in the Rail Plasma Accelerator

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

The Temperature and Pressure in the Plasma Parallel Plate Accelerator

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

Responsible person Ing. Mgr. Radovan Suk