I.V.Vovk, V.S.Malyuga On one method of sound field evaluation for Aeolian tones |
Acoustic bulletin, Vol. 13 ¹ 2, (2010) |
| The paper deals with studying of the problem on generation of the Aeolian tones at laminar flow past the cylinder for the Reynolds numbers of Re≤400. A two-stage technique for evaluating of acoustical characteristics of the Aeolian tones has been developed in the assumption of absent inverse effect of the sound field on the flow. On the first stage, the hydrodynamical problem was solved in the approach of viscous incompressible fluid. In doing so, the parameters have been determined for the occurrence of self-oscillation regime with time-periodic pressure distribution over the cylinder's surface. The found pressure distribution has been used on the second stage for a boundary condition when solving the problem of linear acoustics. The obtained hydrodynamic and acoustical characteristics are in good agreement with the experimental and theoretical data from other researchers. The known approximate estimates of the Aeolian tones sound intensity and lift oscillation amplitude in form of power dependences from incident flow velocity are shown to be inaccurate and the power index significantly depends on Re. The analysis of contributions of different modes of the Aeolian tones in overall sound signal demonstrates the predomination of the first (dipole) component. However, notable increase of the next (quadruple) component with Re is observed. |
|
KEY WORDS: flow past the cylinder, the Aeolian tones, the Reynolds number, the Strouhal number, Lighthill’s acoustic analogy, multipoles, the finite-volume method |
| TEXT LANGUAGE: Russian |