Showing papers in "Journal of Sound and Vibration in 1980"

TL;DR: In this paper, the boundary condition on the acoustic perturbation velocity at an impermeable surface in a flow is considered for the cases in which the surface generates a sound field by vibration or is acoustically deformed by an incident sound field.

TL;DR: In this paper, the wavevector-frequency spectrum of turbulent wall pressure is modeled with regard to the entire incompressible, inviscid domain, at both convective and low wavenumbers.

TL;DR: In this article, the influence of a crack in a welded joint on the dynamic behavior of a structural member is discussed and the relation between the change in natural frequency of vibration of a cantilever beam and the crack depth that appears at the built-in edge which is clamped by way of a weld is investigated.

TL;DR: In this article, an experimental study of the flow field and acoustic properties of a low Reynolds number M = 0.9 jet has been performed in a low pressure anechoic test chamber.

TL;DR: In this paper, a review of propeller noise prediction technology is presented which highlights the developments in the field from the successful attempt of Gutin to the current sophisticated techniques, and two methods for the predictions of the discrete frequency noise from conventional and advanced propellers in forward flight are described.

TL;DR: In this paper, the authors present an introduction to power flow analysis techniques and a study of the simplification of practical structural analysis by use of the frequency response characteristics of an equivalent infinite structure.

TL;DR: In this paper, a general formula for the rate at which acoustic energy is dissipated at the sharp edges of a rigid boundary by the generation of vorticity in the presence of a low, subsonic mean flow of uniform mean density was established.

TL;DR: In this article, it has been shown that a low frequency sound wave can be absorbed significantly when transmitted through a nozzle and a jet flow and that this absorption effect is not restricted just to jet flows but occurs also in flows through apertures or through blade rows.

TL;DR: In this article, the use of integral equation methods in numerical calculations of exterior sound fields around scattering objects was investigated, where the objects investigated are a rigid body with edges and vertices, a rigid plate and an absorbing body.

TL;DR: In this article, inversion of the linear power balance equations is used to determine the plate loss factors and the coupling loss factors in situ, and good agreement is obtained between the predicted and measured coupling loss factor and between the in situ loss factor, for each plate separately also in steady state from power injection measurements.

TL;DR: In this article, the Rayleigh-Ritz method is applied to the prediction of the natural frequencies of flexural vibration of square plates having general boundary conditions, based on the use of Mindlin plate theory so that the effects of shear deformation and rotary inertia are included.

TL;DR: In this paper, the response to a convected harmonic pressure is found by using Fourier transforms and the response is seen to consist of an infinite set of space harmonics whose amplitudes are found explicitly.

TL;DR: In this paper, the authors investigated the duration of the noise emission of a jet by measuring the instantaneous cross-correlation between the far field acoustic pressure and the velocity component in the jet towards the microphone.

TL;DR: In this paper, the power flowing through the isolators and into the supporting foundation of a machine is examined by approximating the driving point frequency response function of the foundation and two-stage isolation of machines with internal force or velocity sources is considered.

TL;DR: In this article, a Galerkin finite element method is presented for studying non-linear vibrations of beams describable in terms of moderately large bending theory, and the exact mode shape and the frequency corresponding to the reference amplitude of vibration are determined by solving iteratively a series of eigenvalue problems until the required convergence is obtained.

TL;DR: In this paper, the response of infinite periodically stiffened fluid-loaded plates is examined for line and point force excitations, and the responses are given as a single and double integral, respectively.

TL;DR: In this paper, the vibrational behavior of a beam rotating with constant spin about its longitudinal axis has been investigated for all possible combinations of free, clamped, simply-supported and guided boundaries.

TL;DR: In this paper, the relative acoustical performance of a number of relatively novel noise barriers in typical highway situations was evaluated by scale model testing of a variety of barrier types, including thin, wide, T-profiled, cylindrically topped, corrugated, inclined, Y-profiant, arrow-profi cation, and some treated with sound absorptive material.

TL;DR: In this paper, the problem of finding the natural frequencies of free vibration of a simply supported circular plate has a straightforward solution, but very few numerical results are available in the literature.

TL;DR: In this paper, a survey conducted in a physically homogeneous neighborhood revealed substantial differences among individuals in their evaluations of the neighborhood's environmental quality, such as noise, privacy, air quality, neighborhood amenities, and general neighborhood satisfaction.

TL;DR: In this paper, a general substructure synthesis method is developed for the dynamic analysis of complex flexible structures, where the motion of each substructure is represented by a given number of substructure admissible functions.

TL;DR: In this paper, the authors studied the propagation and power flow due to force and torque (moment) excitation at the driving point and in the far field of an infinite plate with a single line-stiffener.

TL;DR: In this article, a single Helmholtz resonator is coupled to an enclosure and tuned to the natural frequency of one of its low-order acoustic modes, and the effect on the free, and forced, vibrations of the fluid in the enclosure is analyzed.

TL;DR: In this article, the role of measurement errors is analyzed and it is shown that the smaller the loss factor the higher the measurement accuracy that is needed, and disregarding the longitudinal wave motion of the specimen at higher frequencies leads to an apparent increase of the dynamic modulus and to a apparent decreases of the loss factors.

TL;DR: In this article, a mathematical model for the transmission of an oblique plane sound wave into a laminated composite circular cylindrical shell was presented for a narrow-bodied jet transport.

TL;DR: In this paper, a solution for the sound radiation from a point-excited infinite fluid-loaded plate which is reinforced by two sets of parallel stiffeners is developed by using Fourier wavenumber transforms, and the stationary phase approximation is used to find an expression for the far field pressure.

TL;DR: In this article, the effects of both initial deflection and initial axial displacement on the static deflection as well as the lower natural frequencies were analyzed for non-linear vibrations of a clamped beam under uniformly distributed periodic lateral loading.

TL;DR: In this article, the use of the boundary elements technique permits precise evaluation of the acoustic pressure field diffracted by barriers of different shapes on a flat ground, and different examples are investigated and excess attenuations obtained by shape changes are compared.