Scientific Research and Essays

  • Abbreviation: Sci. Res. Essays
  • Language: English
  • ISSN: 1992-2248
  • DOI: 10.5897/SRE
  • Start Year: 2006
  • Published Articles: 2754

Full Length Research Paper

Calculation of time-varying mean velocity by different methods and determination of turbulence intensities

Gökçen Bombar1*, Mehmet Åžükrü Güney1, Gökmen Tayfur2 and Åžebnem Elçi2
1Civil Engineering Department, Dokuz Eylul University, Izmir 35160, Turkey. 2Civil Engineering Department, Izmir Institute of Technology, Izmir 35430, Turkey.
Email: [email protected]

  •  Accepted: 17 February 2010
  •  Published: 31 March 2010

Abstract

The raw velocity data for both stream-wise and transversal directions in unsteady flows, which are formed by generating input hydrograph, are obtained by using a flow tracker. The same hydrograph is generated 15 times and the mean values are found by calculating the average of all hydrographs. The time varying mean is obtained by using FFT, moving average, wavelet and EMD methods. The best time varying mean is selected according to prescribed criteria. Then, the 15 time series are processed and the stream-wise and transversal turbulence intensities are obtained. The mean of the product of fluctuations is also determined.

 

Key words: Unsteady flow, instantaneous velocity measurement, flow tracker, data processing.