The Study of Vortical Structures Evolution and Spreading Characteristics of A Plane Jet Impinging Upon a small Cylinder

  • 張 軒華

Student thesis: Master's Thesis


In this study the evolution of the coherent structures and the spreading characteristics of a small cylinder impinging plane jet are investigated experimentally by means of hot-wire measurements Throughout the experiments the jet exit velocity is fixed at 10 m/sec and the Reynolds number corresponding to the nozzle width is 7 792×10^3 There are three different impinging length cases: (1) the impinging length of 2H for the near-field impingement (2) 4 5H for the end-of-potential-core impingement and (3) 7H for the far-field impingement The aim of this report is to compare the improvement of those three impingement cases Mean velocity measurement and FFT(Fast Fourier Transform) spectral analysis are applied to interpret the the dynamics of coherent structures The results indicated that the existence of the cylinder in the jet flow truly changed the jet flow After comparing the spreading characteristics between three different impinging length condition The near-field impingement case and the end-of-potential-core impingement case have better improvement to spreading characteristics Otherwise the spectral analysis results also proved the feedback mechanism which mentioned by Ho and Nosseir
Date of Award2014 Aug 19
Original languageEnglish
SupervisorWei-Cheng Wang (Supervisor)

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