Results 261 to 270 of about 40,475 (306)

Generation of Tollmien–Schlichting waves by harmonic excitation

Physics of Fluids, 1994
The creation of wavy disturbances (Tollmien–Schlichting waves) by a localized two-dimensional disturbance source vibrating periodically at a fixed frequency in a Blasius boundary layer is discussed. The initial-boundary value problem mathematically models the vibrating ribbon experiment of Schubauer and Skramstad. By considering the ribbon vibration to
Sengupta, T. K., Ballav, Manish, Nijhawan, Sandeep   +2 more
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Coded excitation for harmonics imaging

1996 IEEE Ultrasonics Symposium. Proceedings, 2002
For harmonics imaging, coded and chirped low level excitations are investigated in order not to break the microballoon contrast agent, and not to cause spectrum leakage via nonlinear propagation distortion of the transmission pulse. A half frequency square-root amplitude apodized signal is proposed to match to the harmonic domain matched filter after ...
openaire   +1 more source

Nonlinear Vibrations of a Beam Under Harmonic Excitation

Journal of Applied Mechanics, 1970
A straight beam with fixed ends, excited by the periodic motion of its supporting base in a direction normal to the beam span, was investigated analytically and experimentally. By using Galerkin’s method (one mode approximation) the governing partial differential equation reduces to the well-known Duffing equation.
Tseng, W. Y., Dugundji, John
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Impacting under harmonic excitation

Journal of Sound and Vibration, 1979
Abstract The steady state response of a one dimensional linear oscillator impacting under harmonic excitation on to rigid obstructions with a coefficient of velocity restitution is investigated. Numerical experiments are discussed and an expression of the steady state velocity for one sided impacting is derived.
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Estimate of the region of attraction of a Kapitza pendulum subject to an harmonic excitation and analysis of the pendulum behavior for a non harmonic excitation

2013 10th International Conference on Electrical Engineering, Computing Science and Automatic Control (CCE), 2013
In this work, we present a stability analysis of the inverted pendulum subjected to a vertical excitation in the suspension point. First we apply a harmonic excitation term and physically determine the attraction region when considering a damping term, this can be seen as the estimation of the degree of robustness of the pendulum subjected to an open ...
Josue Javier Téllez, Joaquín Collado
openaire   +1 more source

Experimental study of gear rattle excited by a multi-harmonic excitation

Applied Acoustics, 2007
Abstract This paper deals with the rattle noise, caused by the fluctuations of the engine torque (acyclic excitation) which, under special conditions, can cause multiple impacts inside the gearbox. Its aim is to experimentally describe the rattle phenomenon in a gearbox.
M. Barthod, B. Hayne, J.-L. Tébec, J.-C. Pin   +3 more
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Collisional Excitation of Vibrational Energy of an Initially Excited Harmonic Oscillator

The Journal of Chemical Physics, 1971
An analytical formula for the phase-averaged vibrational energy transfer to an initially excited harmonic oscillator is presented.
S. J. Yao, H. Y. Sun Yao
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Harmonic Displacement Excitation at a Support

Journal of Mechanical Engineering Science, 1972
The various uses to which receptances may be put in linear vibration theory are well known. For some purposes it would be useful to have the direct receptance at a co-ordinate expressed in terms of parameters of that modified system which is defined when the co-ordinate concerned is locked.
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Non-linear vibrations of a harmonically excited autoparametric system

Journal of Sound and Vibration, 1982
Harmonic forced vibration of a spring-mass-damper system with a parametrically excited pendulum hinged to the mass is investigated. Two types of restoring forces on the pendulum are considered. The method of harmonic balance is used to evaluate the system response. The results are also verified by numerical integration.
Hatwal, H., Mallik, A. K., Ghosh, A.
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On the Excitation of Time Harmonic Cylindrical Surface Acoustic Waves

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 1986
Reciprocity theorem is used to study the excitation of time harmonic cylindrical surface acoustic waves in a semi-infinite isotropic medium. Excitations by point and partial ring sources with applica- tions to laser generated ultrasound are investigated.
Safaai-Jazi, Ahmad, Jen, Cheng-Kuei, Farnell, G. W.   +2 more
openaire   +3 more sources