The Aeroacoustics of Trailing Edges

Blake, William K.; Gershfeld, Jonathan

doi:10.1007/978-3-642-83831-6_10

Cited by 27 publications

(19 citation statements)

References 23 publications

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“…The strength of the unsteady interaction responsible for sound generation then decreases exponentially with increasing frequency, and predicted levels of edge noise are signi"cantly smaller than estimates made by modelling the interaction in terms of a rigid half-plane. This conclusion ignores possible contributions to sound generation from turbulence in the recirculating zone between the separation streamline and the curved section of the upper surface between the separation point and the edge, which are probably signi"cant only at much lower frequencies [2].…”

Section: Resultsmentioning

confidence: 98%

“…In this paper, equation (2) will be applied to estimate the acoustic pressure frequency spectrum of the high-frequency self-noise generated by turbulent #ow over the rounded edge pro"le. The theory is formulated (in section 2) to enable account to be taken of changes in the mean turbulent boundary layer characteristics with distance from the edge.…”

Section: Introductionmentioning

confidence: 99%

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Trailing Edge Noise at Low Mach Numbers, Part 2: Attached and Separated Edge Flows

Howe

2000

Journal of Sound and Vibration

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Trailing Edge Noise at Low Mach Numbers, Part 2: Attached and Separated Edge Flows

Howe

2000

Journal of Sound and Vibration

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“…Brooks and Hodgson [24] measured suggested some model for blunt and sharp TE airfoil noise. Blake and Gershfeld [25,26] showed that TE vortex shedding was pronounced on both symmetric and blunt TE geometries in their experiments. Prasad and Williamson [27] reviewed vortex dynamics related to the wakes of bluff body.…”

Section: Introductionmentioning

confidence: 92%

Numerical Analysis of Unsymmetric Flatbak Trailing Edge Airfoil to Reduce Turbomachinery Noise in Power Generation Cycle

Kim¹,

T²,

S³

et al. 2017

Preprint

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Abstract:A turbomachinery is essential part in the power generation cycle. But, it is main noise source to annoy workers and users and to make environmental problem. Thus it is important to reduce this noise for operating the power generation cycle. This noise is created by flow instability on rotor blade trailing edge. An airfoil that becomes a section of a rotor blade of a rotating machine is manufactured as a blunt trailing edge (TE) with a round or flatback shape rather than the ideal sharp TE shape for the purposes of producibility and durability. This increases the tonal noise and flow-induced vibration at low frequency owing to vortex shedding behind TE when compared with a sharp TE. In order to overcome this problem, this study investigates the oblique TE shape using numerical simulation. In order to do so, the flow was simulated using large eddy simulation (LES) and the noise was analysed by acoustic analogy coupled with LES result. Once the simulation results were verified using the flatback airfoil measurements of Sandia National Laboratories, numerical prediction was performed for airfoils modified to have oblique trailing edge angles of 60°, 45°, and 30° to analyse the flow and noise characteristics. From the simulation results for an airfoil having an oblique TE, it could be seen that the vortex shedding frequency moves in accordance with the oblique angle and that the vortex shedding noise characteristics change according to this angle when compared to the flatback TE airfoil. Therefore, it is considered that modifying the flatback TE airfoil to have an appropriate oblique angle can reduce noise and change the tonal frequency to a bandwidth that is suitable for mechanical systems.

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“…Forsythe et al (2002) identify the need for extended validation data for base flows. Mean velocity and Reynolds stress profiles, surface pressure distributions Blake and Gershfeld (1989), Blake (1975) …”

Section: Summary Of Validation Data Sets and Levelsmentioning

confidence: 99%

Applications of Eddy Resolving Methods

Tucker

2014

Unsteady Computational Fluid Dynamics in Aeronautics

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The Aeroacoustics of Trailing Edges

Cited by 27 publications

References 23 publications

Trailing Edge Noise at Low Mach Numbers, Part 2: Attached and Separated Edge Flows

Trailing Edge Noise at Low Mach Numbers, Part 2: Attached and Separated Edge Flows

Numerical Analysis of Unsymmetric Flatbak Trailing Edge Airfoil to Reduce Turbomachinery Noise in Power Generation Cycle

Applications of Eddy Resolving Methods

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