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ItemSome predictions of the attached eddy model for a high Reynolds number boundary layerNickels, T. B. ; Marusic, I. ; Hafez, S. ; Hutchins, N. ; Chong, M. S. (Royal Society Publishing, 2007-01)Many flows of practical interest occur at high Reynolds number, at which the flow inmost of the boundary layer is turbulent, showing apparently random fluctuations invelocity across a wide range of scales. The range of scales over which these fluctuationsoccur increases with the Reynolds number and hence high Reynolds number flows aredifficult to compute or predict. In this paper, we discuss the structure of these flows anddescribe a physical model, based on the attached eddy hypothesis, which makespredictions for the statistical properties of these flows and their variation with Reynoldsnumber. The predictions are shown to compare well with the results from recentexperiments in a new purpose-built high Reynolds number facility. The model is alsoshown to provide a clear physical explanation for the trends in the data. The limits ofapplicability of the model are also discussed.
ItemEvidence of the -1-law in a high Reynolds number turbulent boundary layerNickels, T. B. ; Hafez, S. ; Marusic, I. ; Chong, M. S. ( 2004)Dimensional analysis leads to a prediction of a -1-power-lawfor the streamwise velocity spectrum in a turbulent boundarylayer. This law can be derived from overlap arguments or fromphysical arguments based on the attached eddy hypothesis ofTownsend (1976). Some recent experiments have questionedthe existence of this power-law region in wall-bounded ows.In this paper experimental spectra are presented which supportthe existence of the -1-law in a high Reynolds number boundarylayer, measured in the large boundary layer facility in theWalterBasset laboratory at the University of Melbourne. The paperpresents the experimental results and discusses the theoreticaland experimental issues involved in examining the existence ofthe -1-law and reasons why it has proved so elusive.
ItemEvidence of the k1-1 law in a high-Reynolds-number turbulent boundary layerNickels, T. B. ; Marusic, I. ; Hafez, S. ; Chong, M. S. (The American Physical Society, 2005)Dimensional analysis and overlap arguments lead to a prediction of a region in the streamwise velocityspectrum of wall-bounded turbulent flows in which the dependence on the streamwise wave number, k1, isgiven by k 1-1 . Some recent experiments have questioned the existence of this region. In this Letter,experimental spectra are presented which support the existence of the k 1-1 law in a high-Reynolds-numberboundary layer. This Letter presents the experimental results and discusses the theoretical and experimentalissues involved in examining the existence of the k 1-1 law and the reasons why it has proved so elusive.