Techno Press
Techno Press

Wind and Structures
  Volume 24, Number 1, January 2017 , pages 079-93
DOI: https://doi.org/10.12989/was.2017.24.1.079
 


The loss coefficient for fluctuating flow through a dominant opening in a building
Haiwei Xu, Shice Yu and Wenjuan Lou

 
Abstract
    Wind-induced fluctuating internal pressures in a building with a dominant opening can be described by a second-order non-linear differential equation. However, the accuracy and efficiency of the governing equation in predicting internal pressure fluctuations depend upon two ill-defined parameters: inertial coefficient CI and loss coefficient CL, since CI determines the un-damped oscillation frequency of an air slug at the opening, while CL controls the decay ratio of the fluctuating internal pressure. This study particularly focused on the value of loss coefficient and its influence factors including: opening configuration and location, internal volumes, as well as wind speed and approaching flow turbulence. A simplified formula was presented to predict loss coefficient, therefore an approximate relationship between the standard deviation of internal and external pressures can be estimated using Vickery\'s approach. The study shows that the loss coefficient governs the peak response of the internal pressure spectrum which, in turn, will directly influence the standard deviation of the fluctuating internal pressure. The approaching flow characteristic and opening location have a remarkable effect on the parameter CL.
 
Key Words
    wind tunnel test; dominant opening; internal pressure; loss coefficient; Helmholtz resonance
 
Address
Haiwei Xu, Shice Yu and Wenjuan Lou: College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China
 

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