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EAWE PhD-Seminar, Risø 4. October

EAWE PhD-Seminar, Risø 4. October. PhD-Student Brian Riget Broe Semi-Empirical modeling of Aerodynamical Noise Risø National Laboratory Frederiksborgvej 399 4000 Roskilde, Denmark Aeroacoustics and Fluctuating Lift. Sources of aerodynamic noise. From Moriarty (2003).

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EAWE PhD-Seminar, Risø 4. October

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  1. EAWE PhD-Seminar, Risø 4. October PhD-Student Brian Riget Broe Semi-Empirical modeling of Aerodynamical Noise Risø National Laboratory Frederiksborgvej 399 4000 Roskilde, Denmark Aeroacoustics and Fluctuating Lift

  2. Sources of aerodynamic noise From Moriarty (2003) EAWE PhD-Seminar, Risø 4.-5. October, 2006

  3. Modeling the inflow noise Model by Amiet (1975) The power spectrum of the surface pressure Task: Find the Fluctuating lift for an arbitrary profile EAWE PhD-Seminar, Risø 4.-5. October, 2006

  4. 2-D gust on a flat plate Sears (1941) and Graham (1971) EAWE PhD-Seminar, Risø 4.-5. October, 2006

  5. 2-D gust on a flat plate, Results Sears (1941) 1-D A sinusoidal gust impinging on a semi-infinite flat plate. k is the wave vector which is in the plane of the flat plate. The wave vector has the component  in the x-direction and  in the y-direction. The wave front hits the edge of the plate in an angle. For the 1-D case  is zero. EAWE PhD-Seminar, Risø 4.-5. October, 2006

  6. Measured surface pressure (1) Measurements by Mish et al. (2006) for a NACA 0015 profile EAWE PhD-Seminar, Risø 4.-5. October, 2006

  7. Measured surface pressure (2) Measurements by Mish et al. (2006) for a NACA 0015 profile EAWE PhD-Seminar, Risø 4.-5. October, 2006

  8. 2-D gust on a profile A sinusoidal gust impinging on a Joukowsky aerofoil. k is the wave vector. The wave vector has the component  in the x-direction and  in the z-direction. For the 1-D case  is zero. Goldstein and Atassi (1976) EAWE PhD-Seminar, Risø 4.-5. October, 2006

  9. Joint lift response of angle attack and camber EAWE PhD-Seminar, Risø 4.-5. October, 2006

  10. Lift response due to thickness EAWE PhD-Seminar, Risø 4.-5. October, 2006

  11. Summary • A function for the fluctuating lift needs to be found for an arbitrary profile • Measurements of the surface pressure is going to be made by Risø for a Risø profile • Work on model by linearized theory to find the fluctuating lift due thickness EAWE PhD-Seminar, Risø 4.-5. October, 2006

  12. References Listed in order of appearence • P. Moriarty and P. Migliore, Semi-Empirical Aeroacoustic Noise Prediction Code for Wind Tubines, 2003, NREL/TP-500-34478. • R. K. Amiet, Acoustic Radiation From An Airfoil In A Turbulent Stream, 1975, J. Sound and Vibr., 41(4), 407-420. • P. F. Mish and W. J. Devenport, An experimental investigation of unsteady surface pressure on an airfoil in turbulence-Part 1: Effects of mean loading, 2006a, J. Sound and Vibr., 296, 417-446. • W. R. Sears, Some Aspects of Non-Stationary Airfoil Theory and Its Practical Application, 1941, J. of the Aeronatical Sc., Vol. 8, No. 3, 104-108. • J. M. R. Graham, Lifting Surface Theory for the Problem of an Arbitrarily Yawed Sinusoidal Gust Incident on a Thin Aerofoil in Imcompressible Flow, 1971, The Aeronautical Quart., 182-198. • M. E. Goldstein and H. Atassi, A complete second-order theory for the unsteady flow about an airfoil due to a period gust, 1976, J. Fluid Mech., vol. 74, part 4, 741-765. • H. M. Atassi, The Sears problem for a lifting airfoil revisited – new results, J. Fluid Mech., 1984, vol. 141, 109-122. EAWE PhD-Seminar, Risø 4.-5. October, 2006

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