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dc.contributor.authorGe, Zhongfuen_US
dc.date.accessioned2014-03-14T20:06:38Z
dc.date.available2014-03-14T20:06:38Z
dc.date.issued2004-12-14en_US
dc.identifier.otheretd-01082005-001412en_US
dc.identifier.urihttp://hdl.handle.net/10919/25965
dc.description.abstractThe full-scale value of the Reynolds number associated with wind loads on structures is of the order of 10^7. This is further complicated by the high levels of turbulence fluctuations associated with strong winds. On the other hand, numerical and wind tunnel simulations are usually carried out at smaller values of Re. Consequently, the validation of these simulations should only be based on physical phenomena derived with tools capable of their identification. In this work, two physical aspects related to extreme wind loads on low-rise structures are examined. The first includes the statistical properties and prediction of pressure peaks. The second involves the identification of linear and nonlinear relations between pressure peaks and associated velocity fluctuations. The first part of this thesis is concerned with the statistical properties of surface pressure time series and their variations under different incident flow conditions. Various statistical tools, including space-time correlation, conditional sampling, the probability plot and the probability plot correlation coefficient, are used to characterize pressure peaks measured on the top surface of a surface-mounted prism. The results show that the Gamma distribution provides generally the best statistical description for the pressure time series, and that the method of moments is sufficient for determining its parameters. Additionally, the shape parameter of the Gamma distribution can be directly related to the incident flow conditions. As for prediction of pressure peaks, the results show that the probability of non-exceedence can best be derived from the Gumbel distribution. Two approaches for peak prediction, based on analysis of the parent pressure time series and of observed peaks, are presented. The prediction based on the parent time series yields more conservative estimates of the probability of non-exceedence. The second part of this thesis is concerned with determining the linear and nonlinear relations between pressure peaks and the velocity field. Validated by analytical test signals, the wavelet-based analysis is proven to be effective and accurate in detecting intermittent linear and nonlinear relations between the pressure and velocity fluctuations. In particular, intermittent linear and nonlinear velocity pressure relations are observed over the nondimensional frequency range fH/U<0.32. These results provide the basis for flow parameters and characteristics required in the simulation of the wind loads on structures.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartdissertation.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectvelocity and pressure fluctuationsen_US
dc.subjecthigher-order spectraen_US
dc.subjectwaveleten_US
dc.subjectstatisticsen_US
dc.subjectpressure coefficienten_US
dc.subjectLow-rise structuresen_US
dc.subjectwind loadsen_US
dc.titleAnalysis of surface pressure and velocity fluctuations in the flow over surface-mounted prismsen_US
dc.typeDissertationen_US
dc.contributor.departmentEngineering Science and Mechanicsen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineEngineering Science and Mechanicsen_US
dc.contributor.committeechairHajj, Muhammad R.en_US
dc.contributor.committeememberKohler, Werner E.en_US
dc.contributor.committeememberMasoud, Ziyad N.en_US
dc.contributor.committeememberHenneke, Edmund G. IIen_US
dc.contributor.committeememberRagab, Saad A.en_US
dc.contributor.committeememberTieleman, Henry W.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-01082005-001412/en_US
dc.date.sdate2005-01-08en_US
dc.date.rdate2008-01-12
dc.date.adate2005-01-12en_US


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