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Large Eddy Simulation of Excited Jet Flow

Ghadimi, Masoud | 2016

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 48945 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Farshchi, Mohammad
  7. Abstract:
  8. Excited jet flow has many physical and industrial applications, e.g. in aeroacoustics and the combustion instability. Analysis of this type of flow needs an accurate simulation of flow dynamics. This work presents the large eddy simulation of this type of flow. The numerical method used in the large eddy simulation must have low numerical dissipation and high order of accuracy. Compact methods which satisfy these requirements and have high resolution of frequency, are favorable ones for the large eddy simulation. A fourth-order compact finite volume method which had been developed in the MSc thesis of the author is extended and completed in the present work. This extension includes the adaption of method for the compressible flows, curvilinear grids and multi-block domains. Two new filtering methods are proposed and assessed in the present work. The first one is high accurate and used inside the domain for filtering of parameters in the large eddy simulation. The second one is dissipative and used to annihilate vortices in the sponge zones near the outlet boundary. Thomson and NSCBC boundary conditions are added to the software for the accurate simulations. The turbulence generation is made by different methods such as the inverse Fourier transformation of Lee and digital filtering of Klein. The large eddy simulation of turbulent jet is validated by the previous valuable numerical and experimental results. The natural frequencies of jet are extracted by FFT of fluctuations at different points. Two dominant frequencies are investigated in the jet flow related to the shear layer and jet-preferred modes. The large eddy simulation of jet flow, excited by these frequencies and harmonic of them, shows the real nature of these modes
  9. Keywords:
  10. Large Eddy Simulation (LES) ; Compact Finite Volume Method ; Combustion Instability ; Large Eddy Simulation (LES) ; Fourth Order Compact Finite Volume ; Filtering Approaches ; Excited Jet Flow

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