Showing papers in "Journal of Fluids and Structures in 1990"

TL;DR: In this article, the Strouhal number of a family of rectangular cylinders with side ratios (B/D) ranging from 0·04 to 1·0 and with angles of attack from 0° to 90° are presented.

TL;DR: In this paper, the authors investigated the wake structure of a circular disk in the Reynolds number range 1·5 × 104Re3 × 105 at low values of Mach number and showed that the wake is dominated by three instability mechanisms: axisymmetric pulsation of the recirculation bubble at very low frequency f 1(S1 = f1D/Uo ≅ 0·05); antisymmetry fluctuations induced by a helical vortex structure at a natural frequency fnSn = fnD/uo≅ 0.135); and a high frequency instability

TL;DR: In this paper, the authors investigated aqueous flow through silicone rubber tubes held open at both ends and externally pressurized, and found that the tube oscillations can be divided into well-separated bands of low, intermediate and high frequency, within each of which the frequency generally increases gradually with flow-rate and external pressure.

TL;DR: In this article, the authors used the finite element method and a discrete-vortex model to predict the observed separated flow and the amount of acoustic energy generated is a function of the phase of the acoustic cycle at which the vortex passes the baffle.

TL;DR: In this article, the authors investigated the random excitation mechanism of tube arrays in cross-flow, also often called "turbulent buffeting" and concluded that random forces produced by air-water and by steam-water mixtures would be of the same order of magnitude.

TL;DR: In this paper, a general three-field variational principle is obtained for the motion of an acoustic fluid enclosed in a rigid or flexible container by the method of canonical decomposition applied to a modified form of the wave equation in the displacement potential.

TL;DR: In this article, a simple model is presented which accounts for the key aspects of dry friction and is well suited to the efficient explicit numerical integration schemes, specifically through nonlinear modal superposition.

TL;DR: In this article, the authors analyzed the viscous fluid-dynamic forces and the moments acting on the walls of a one-dimensional, narrow, tapered passage when one wall is vibrating in coupled translational and rotational modes.

TL;DR: In this paper, the authors identified regions of greatest nonuniformity behind a single row and two rows of tubes and found that gap flows were significant in the range 1 T/D ≤ 5 1·75 and disappeared beyond T /D = 2·1.

TL;DR: In this paper, the stability of a rigid, thin plate able to execute coupled translational and rotational vibrations in a one-dimensional, narrow, tapered passage is studied, and the critical flow rates, natural frequencies and modes on the stability boundaries determined both theoretically and experimentally.

TL;DR: In this paper, two mathematical models were examined in an attempt to explain the behaviour of the fluctuating normal force induced by the transverse oscillation of a square-section cylinder in flow.

TL;DR: In this article, exact complex-valued nonsymmetric transcendentally frequency-dependent member stiffness matrices have been established for uniform Rayleigh-Timoshenko beams, uniform Euler-Bernoulli beams, and also for uniform strings (with zero bending stiffness).

TL;DR: In this article, a method called Identification Modale Excitation Non Evaluee (IMENE) was proposed to estimate modal parameters of a coupled fluid-structure system from structural response data without any excitation measurement.

TL;DR: In this article, two computational procedures, one solving the compressible Navier-Stokes equations and the other solving the incompressible NNDE, have been used to analyse two-dimensional flows which exhibit deep, prolonged stall.

TL;DR: In this article, a finite element computer program has been developed to represent such a pipe as a frequency dependent elasto-acoustic super-element: the degrees of freedom of the internal nodes are eliminated for a prescribed frequency.

TL;DR: In this article, the phase angle between the displacements of adjacent cylinders has been shown to have an important effect on the stability of cylinder arrays subject to cross-flow, especially for high values of non-dimensional mass-damping, mδ / ρd 2.

TL;DR: In this paper, the vibrational properties of circular cylinders subjected to a cross-flow which is not uniform, but jetted from a narrow gap, were studied experimentally, and it was found that phenomena which look like vorticity sheddingding-induced vibration and fluidelastic instability could be observed in circular cylinders, similar to those observed in uniform crossflow, exist in the jetted flow case.

TL;DR: In this paper, the fluid and squeeze film characteristics inside cylindrical heat exchanger tube support holes and at anti-vibration bar (AVB) supports were determined experimentally.

TL;DR: In this article, the authors show that the resonance spectrum of a fluid-bundle system is continuous and therefore spread over an interval, and then they compute the limits of this interval for incompressible and compressible fluids.

TL;DR: In this article, cross-bispectral analysis is used to investigate the coupling between a vibrating cylinder and the velocity field in its wake at low Reynolds numbers [Re = O(10^2).

TL;DR: In this article, a nonlinear, quasi-steady analysis of the wake-induced instability of a leeward conductor in the wake of a second identical windward conductor has been developed.

TL;DR: The role of turbulence in the oscillating flow field is examined in detail in this article, where it is observed that the flow in the impingement region is composed of an almost periodically recurring arrangement of vortices differing significantly from those observed in the equivalent laminar case.

TL;DR: In this paper, the generation of noise by vortex buffeting on a pair of cylinders in tandem in unsteady high-Reynolds-number flow is investigated analytically, and numerical results for several initial vortex configurations are presented in extensive graphs and characterized in detail.

TL;DR: An experimental program of research has been conducted on a three-span array of tubes in a specially designed wind tunnel as discussed by the authors, which consisted of 68 brass 15·9 mm diameter tubes, arranged in a normal triangular geometry with a pitch-to-diameter ratio of 1·4.

TL;DR: In this article, the authors investigated the effects of eccentricity on annular diffusers and found that the instability can be completely suppressed by carefully adjusting the imposed vibration amplitude and frequency, leaving the flow in its nonoscillatory state.

TL;DR: In this article, a series of measurements of the squeeze film force components for planar sinusoidal motions are presented, where the amplitude and phase angle of each harmonic has been measured using a two-channel FFT analyzer and the force components in-phase and out-of-phase with the displacement are computed to give coefficients for each harmonic.

TL;DR: Using the Krylov and Bogoliubov (1949, Introduction to Non-Linear Mechanics, Princeton: Princeton University Press) method of averaging, solutions have been obtained to the previously developed nonlinear equations of motion for wake-induced flutter of one circular cylinder in the wake of a fixed similar cylinder as discussed by the authors.

TL;DR: In this paper, the authors examined the modes of vibration for a system consisting of an air or water layer between a rigid sphere and a concentric rigid shell, a steel sphere and an inner rigid shell and showed that low frequency circumferential modes exist in the air layer about the steel sphere which correspond quite well to the low frequencies of acoustic waves emitted when several steel spheres collide in air.

TL;DR: In this paper, the authors present experimental measurements of forces and response displacements from a spring-mounted vertical cylinder in regular waves for a constant surface Keulegan-Carpenter number, SKC, equal to 8 and frequency ratios in the range 0·3≤ ǫw/ǫNw≤0·8.