Power Spectral Density Model of Torsional Dynamic Wind Loads on Tall Buildings

2012 ◽  
Vol 164 ◽  
pp. 433-436
Author(s):  
Tian Yin Xiao
Keyword(s):  
Wind Tunnel ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Cross Sections ◽  
Wind Tunnel Test ◽  
Power Spectra ◽  
Tall Buildings ◽  
Wind Loads ◽  
Side Ratio ◽  
Power Spectral

9 models of tall buildings with different rectangular cross-sections are tested in a wind tunnel. After processing and analyzing the measured data of fluctuating pressure on the models, the effects of models’height, aspect ratio, side ratio on the power spectra of torsional wind loads are studied. New formulas of power spectral density of torsional wind loads are proposed by curve fitting method. The applicability of the formulas has been verified by the results from the wind tunnel test.

Analysis of turbulence power spectra and velocity correlations in a pipeline with obstructions

2017 ◽  
Vol 28 (02) ◽  
pp. 1750019 ◽  
Author(s):  
A. T. da Cunha Lima ◽  
I. C. da Cunha Lima ◽  
M. P. de Almeida
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Cross Sections ◽  
Power Spectra ◽  
Low Frequency ◽  
Frequency Range ◽  
Frequency Space ◽  
Power Spectral ◽  
Power Spectral Densities ◽  
Low Frequency Power

We calculate the power spectral density and velocity correlations for a turbulent flow of a fluid inside a duct. Turbulence is induced by obstructions placed near the entrance of the flow. The power spectral density is obtained for several points at cross-sections along the duct axis, and an analysis is made on the way the spectra changes according to the distance to the obstruction. We show that the differences on the power spectral density are important in the lower frequency range, while in the higher frequency range, the spectra are very similar to each other. Our results suggest the use of the changes on the low frequency power spectral density to identify the occurrence of obstructions in pipelines. Our results show some frequency regions where the power spectral density behaves according to the Kolmogorov hypothesis. At the same time, the calculation of the power spectral densities at increasing distances from the obstructions indicates an energy cascade where the spectra evolves in frequency space by spreading the frequency amplitude.

Refined Mathematical Models for Across-Wind Loads of Rectangular Tall Buildings with Aerodynamic Modifications

2021 ◽  
pp. 2150131
Author(s):  
Yi Li ◽  
Chao Li ◽  
Qiu-Sheng Li ◽  
Yong-Gui Li ◽  
Fu-Bin Chen
Keyword(s):  
Wind Tunnel ◽  
Correlation Coefficients ◽  
Tall Buildings ◽  
Tall Building ◽  
Experimental Results ◽  
Dynamic Loads ◽  
Wind Loads ◽  
Empirical Formulas ◽  
Benchmark Model ◽  
Power Spectral

This paper aims to systematically study the across-wind loads of rectangular-shaped tall buildings with aerodynamic modifications and propose refined mathematic models accordingly. This study takes the CAARC (Commonwealth Advisory Aeronautical Research Council) standard tall building as a benchmark model and conducts a series of pressure measurements on the benchmark model and four CAARC models with different round corner rates (5%, 10%, 15% and 20%) in a boundary layer wind tunnel to investigate the across-wind dynamic loads of the typical tall building with different corner modifications. Based on the experimental results of the five models, base moment coefficients, power spectral densities and vertical correlation coefficients of the across-wind loads are compared and discussed. The analyzed results shown that the across-wind aerodynamic performance of the tall buildings can be effectively improved as the rounded corner rate increases. Taking the corner round rate and terrain category as two basic variables, empirical formulas for estimating the across-wind dynamic loads of CAARC standard tall buildings with various rounded corners are proposed on the basis of the wind tunnel testing results. The accuracy and applicability of the proposed formulas are verified by comparisons between the empirical formulas and the experimental results.

Analysis on Wind-Induced Vibration of Tall Buildings in Hilly Terrain

2014 ◽  
Vol 580-583 ◽  
pp. 2567-2571
Author(s):  
Yi Sun ◽  
Nuan Deng ◽  
Zheng Liang Li
Keyword(s):  
Wind Tunnel ◽  
Wind Field ◽  
Wind Tunnel Test ◽  
Tall Buildings ◽  
Wind Load ◽  
Wind Loads ◽  
Test Results ◽  
Hilly Terrain ◽  
Flat Terrain ◽  
Wind Induced Vibration

The responses of tall buildings under wind loads in hilly terrain are remarkably different from that in flat terrain. Wind load codes can’t work efficiently or directly to calculate the wind-induced vibration of tall buildings in hilly terrain. Utilizing some wind tunnel test results of wind field in hilly terrain and pressures on tall buildings, the access to response of tall buildings on hilly terrain were provided. Some effects from hill characteristics to building responses were discussed.

scholarly journals Comparison of Semi-Empirical Single Point Wall Pressure Spectrum Models with Experimental Data

Fluids ◽  
2021 ◽  
Vol 6 (8) ◽  
pp. 270
Author(s):  
Nicholas Thomson ◽  
Joana Rocha
Keyword(s):  
Wind Tunnel ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Mean Squared Error ◽  
Single Point ◽  
Flight Test ◽  
Wall Pressure ◽  
Squared Error ◽  
Power Spectral ◽  
Semi Empirical

This study presents an evaluation of semi-empirical single-point wall pressure spectrum models by comparing model predictions with wind tunnel and flight test data. The mean squared error was used to compare the power spectral density of the wall pressure fluctuations predicted by semi-empirical models with a large amount of experimental data. Results show that the models proposed by Goody and Smol’yakov have the lowest mean squared error when predicting the power spectral density for wind tunnel experiments and the Rackl and Weston model has the lowest mean squared error when predicting the power spectral density for flight test data. In addition, although current studies of the power spectra obtained in the wind tunnel are similar, they are not generally an accurate representation of flight test experiments.

Study of the dynamic response of a CAARC building by the synthetic wind method and comparison with different approaches

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lucas Willian Aguiar Mattias ◽  
Carlos Andres Millan Paramo
Keyword(s):  
Wind Tunnel ◽  
Dynamic Response ◽  
Good Accuracy ◽  
Wind Tunnel Test ◽  
Power Spectra ◽  
Tall Buildings ◽  
Experimental Results ◽  
Content Type ◽  
Different Types ◽  
Numerical Approaches

Purpose This paper analyzes the effect that is generated in the dynamic response of a Commonwealth Advisory Aeronautical Council building for different types of power spectra. This article also compares synthetic wind method (SWM) results with wind tunnel tests and other numerical approaches.Design/methodology/approach One of the main methodologies developed in Brazil, the SWM, is employed to determine the dynamic wind loads. The Davenport, Lumley and Panowski, Harris, von Karman and Kaimal model are used in SWM to generate the resonant harmonics. Lateral pressures are calculated by the wind speed deflection profile for 30, 35, 40 and 45 m/s. The structure is processed in Autodesk Robot Structural Analysis with numerical analysis in FEM by the Hilber–Hughes–Taylor method. To corroborate the synthetic wind with experimental results, displacement curves are developed for wind tunnel experimental results, Davenport method, Eurocode and NBR 6123, together with the SWM.Findings Results show that for 30 m/s, the lowest convergence of the power spectra models was presented and that the greatest difference found was below 10%. In addition, it was shown that Eurocode 1-4 can lead to oversizing, while NBR 6123 can lead to undersizing, compared with the experimental results. Finally, results by the Davenport method, wind tunnel test and synthetic wind showed good accuracy.Originality/value By carrying out this comparative analysis, this work presents an important contribution in the field of calculating the dynamic response of tall buildings. Studies with these comparisons to corroborate the SWM had not yet been carried out.

Fuzzy Modeling of Multi-Degree-of-Freedom Power Spectral Density Systems

2009 ◽  
Vol 2 (1) ◽  
pp. 40-47
Author(s):  
Montasser Tahat ◽  
Hussien Al-Wedyan ◽  
Kudret Demirli ◽  
Saad Mutasher
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Fuzzy Modeling ◽  
Degree Of Freedom ◽  
Power Spectral
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