Vibrations of Chimneys under the Action of the Wind (original) (raw)
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Field Tests on a Full-Scale Steel Chimney Subjected to Vortex-Induced Vibrations
Structural Engineering International, 2021
Industrial chimneys, launch vehicles and stacks are examples of large diameter circular cross section structures which can be prone to crosswind vortex-induced vibrations. VIV has been extensively studied for both fundamental and applied issues, but few documented studies concern high Reynolds number regime (> 5•10 5) in atmospheric turbulent wind. This paper introduces a field test on a slender light and low damped chimney designed to experience "supercritical" VIV at moderate wind velocity. The chimney was recently erected in a wind monitored field, near the Atlantic coast of France. The purpose of this paper is to present the first vibration results obtained during a sequential 13-days period in September 2020. A statistical analysis has been performed on the amplitude and dominant frequency responses and results are reported in term of probability distribution as a function of wind speed and direction. VIV events of low (< 15 % of diameter) to moderate amplitude (> 30 % of diameter) have been highlighted in a range of wind velocity 25 % lower than expected, along with significant influence of the wind direction. Low turbulent easterly wind giving vortex-induced vibrations with the highest amplitude.
Full-scale measurements of wind-induced oscillations of chimneys
Journal of Wind Engineering and Industrial Aerodynamics, 1996
In order to verify the mathematical correlation length model for predicting the vortexinduced vibrations of chimneys, several full-scale measurements on chimneys have been made by the authors. The most extensive measurements have been done with an experimental steel chimney of 28 m height and 0.91 m diameter, which has been erected on the test field of the Technical University Aachen, Germany. Within three years, gust response as well as vortex resonance response have been investigated. The results show a very good agreement with the prediction model. Some other full-scale measurements on full-scale steel chimneys are presented and compared with the prediction model.
Journal of Fluids and Structures, 2017
This paper develops a unified procedure for dealing with gust-excited vibrations and aeroelastic phenomena on slender structures and structural elements in the framework of the Generalized Gust Factor technique. The structure is arbitrarily inclined and constrained, and excited on its fundamental mode. Galloping phenomenon is taken into account considering linearized effects only; vortex-induced oscillations are simulated through a nonlinear equivalent damping based on the classic Vickery and Basu approach. The effectiveness of the procedure is discussed and verified over a selection of circular-shaped structures, object of extensive experimental measures. The model proposed is fully suitable to reproduce the effective structural aeroelastic behavior, also in the synchronization region at lock-in. Large uncertainties, however, arise from the choice of the model parameters, on which the literature is still poor. Particular attention is devoted to the limiting magnitude (which governs the non-linear aerodynamic damping) and to the peak factor (which supplies the maximum response), both these quantities having a crucial role in the assessment of vortex-induced vibrations.
Journal of Wind Engineering and Industrial Aerodynamics, 1983
A model is presented for predicting the across-wind response of slender structures of circular cross-section to turbulent shear flow. Fundamental aspects of the model have been described in a companion paper [ 1 ], the key feature of the model being the representation of all motion-dependent phenomena by a nonlinear damping force. The development described in this paper is concerned with extending the earlier work, which was confined to two-dimensional laboratory configurations, such that the model is able to provide estimates of response for full-scale structures.
A novel spectral method for cross-wind vibrations: Application to 27 full-scale chimneys
Journal of Wind Engineering and Industrial Aerodynamics, 2017
The paper presents a collection of full-scale data selected from literature concerning measurements of crosswind vibrations of chimneys. They belong to the original set of data, from which current codified methodologies-the Spectral Method by Vickery&Basu (1983) and the Effective Correlation Length Method by Ruscheweyh (1986)were developed. The full-scale samples are critically reviewed; uncertain estimations and observations by eye are discarded. The application of the codified methodologies to the selection of full-scale chimneys reveals several inconsistencies in the prediction of crosswind oscillations. The paper presents a novel Spectral Method, whose predictions reproduce very well the oscillations measured in full-scale. The method is developed through wind tunnel tests in forced-vibrations. The key is the modification of the aeroelastic damping model in the well-known Vickery Spectral Method.
A comparison of crosswind response evaluation for chimneys following different international codes
2009
It is well known that at certain intensities of wind flow velocity acting on a structure, the response of the latter in the transverse direction of flow is induced by alternating vortices. The most important parameters that contribute to the cross wind response are: the intensity of turbulence, the duration of the gusts and the magnitude of the wind speed in the floe direction. Nevertheless, there is not exist an unified criteria to evaluate the cross-wind response and several methodologies has been proposed. In this paper, two of those methodologies for the calculation of total displacements in the transverse direction of the wind flow, are analyzed and described. Also, some procedures proposed in different international design codes to evaluate the cross-wind response of cylindrical structures, are applied to the case of a chimney for comparison. Finally, it is concluded that the method that best estimates the cross response due to vortices, with respect to the results reported in...
A numerical study of wind-induced tower vibrations
Computers & Structures, 1987
The application of the finite element method for the analysis of wind-induced tower vibrations is presented and discussed. In this study simulated wind forcing functions were applied to a 3-D model of an existing illumination tower, and its response was studied under various loading conditions. The obtained numerical results are compared with experimental data for evaluating the accuracy of this approach. NOTATION area on which wind forces act parameter for relating wind velocity with height shape factor, or force factor damping matrix drag coefhcient lift coefficient dimension of body normal to wind flow tower diameter elastic modulus force structural response frequency vortex shedding frequency stitTness matrix mass matrix forcing function vector dynamic head of wind Reynolds number Strouhal number time wind speed kinematic viscosity of air acceleration, velocity and displacement vectors, respectively elevation of points at which wind speed is measured, or computed mass density of air vortex shedding circular frequency
Quantification of the Effects of Turbulence in Wind on the Vortex-induced Vibrations
IABSE Symposium, Kolkata 2013: Long Span Bridges and Roofs - Development, Design and Implementation, 2013
Vortex-induced Vibrations (VIV) of structures may be influenced by the turbulence inherent in the wind. Generally, turbulence is believed to decrease the VIV amplitudes. For a rational design, it important to consider the influence that turbulence has on the VIV phenomenon. This study aims at developing a method for quantifying the effects of turbulence on VIV. Numerical simulations are performed and an approach to generate turbulence by placing geometrical shapes in the flow is used. This is analogous to well accepted laboratory wind tunnel approaches. The generated turbulent flow is studied and the properties of the flow are quantified. An example is presented for the case of a circular cylinder considering different flow situations. The study shows that there is a distinct difference in the resulting vortex shedding behaviour between uniform and turbulent flow. The merits and limitations of the approach are also discussed.