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Puffs turbulents en conduites carrées : rayonnement acoustique et effets de courbure

Abstract : The first occurrence of turbulence at low Reynolds number in pipe flows takes the form of streamwise localised patches named turbulent puffs.In the literature puffs are usually studied in the nominal conditions of incompressible flow in straight circular pipes.This thesis aims at investigating the influence that slight deviations from those nominal conditions have on puffs computed in a square duct configuration. For this purpose we introduce a slight curvature of the pipe on the one hand and we analyse the acoustic field of the puff on the other hand.Curvature effects are analysed by means of a laminar model obtained as an extension of the work by Dean.This model is validated against numerical and experimental literature data, providing satisfactory results. The turbulent puff in a curved pipe is computed with an additional set of equations based on scale separation, the curvature effects on turbulence are in qualitative agreement with the data available in the literature.The far-field noise field generated by a puff is computed by means of an acoustic analogy, in addition to characterising the acoustic field produced, this analysis excludes a role of acoustics in a hypothetical long range interaction between puffs.Moreover this study provides some elements to the literature concerning the role of the viscous stresses to the sound generation. This configuration provides a very well posed case for such analysis, since the effects of viscous stresses on acoustics are most visible at low Mach and Reynolds numbers.
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Submitted on : Monday, February 7, 2022 - 3:53:02 PM
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  • HAL Id : tel-03560524, version 1

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Leonardo Rigo. Puffs turbulents en conduites carrées : rayonnement acoustique et effets de courbure. Mécanique [physics.med-ph]. HESAM Université, 2020. Français. ⟨NNT : 2020HESAE047⟩. ⟨tel-03560524⟩

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