Computational Aeroacoustics for Rotating Systems with Application to an Axial Fan

Hüppe, Andreas; Reppenhagen, Aaron; Zenger, Florian; Becker, Stefan

doi:10.2514/1.j055931

Cited by 24 publications

(31 citation statements)

References 21 publications

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“…For the aeroacoustic modeling, we investigate two sound propagation models. The integral equation according to Ffowcs Williams and Hawkings analogy (FWH) in Farassat's 1A version [10] and the finite element formulation of the perturbed convective wave equation (PCWE) [11].…”

Section: Introductionmentioning

confidence: 99%

Computational aeroacoustics of the EAA benchmark case of an axial fan

Schoder

Junger

2020

Acta Acust.

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This contribution benchmarks the aeroacoustic workflow of the perturbed convective wave equation and the Ffowcs Williams and Hawkings analogy in Farassat’s 1A version for a low-pressure axial fan. Thereby, we focus on the turbulence modeling of the flow simulation and mesh convergence concerning the complete aeroacoustic workflow. During the validation, good agreement has been found with the efficiency, the wall pressure sensor signals, and the mean velocity profiles in the duct. The analysis of the source term structures shows a strong correlation to the sound pressure spectrum. Finally, both acoustic sound propagation models are compared to the measured sound field data.

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Section: Introductionmentioning

confidence: 99%

Computational aeroacoustics of the EAA benchmark case of an axial fan

Schoder

Junger

2020

Acta Acust.

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“…The second verification example is based on the perturbed convective wave equation (PCWE) with the substantial derivative of the incompressible pressure as aeroacoustic excitation

\frac{1}{c^{2}} \frac{D^{2} ψ^{a}}{D t^{2}} - Δ ψ^{a} = \frac{1}{ρ_{0} c^{2}} \frac{D p^{ic}}{D t} .

…”

Section: Numerical Examplementioning

confidence: 99%

“…Naturally, the RBF framework is carried out on the discretization of the flow simulation, since this discretization already resolves characteristic flow structures. As a third step, a conservative integration of the source terms ensures a nondissipative calculation of the aeroacoustic finite element sources that are applied to the finite element simulation. Finally, the acoustic simulation is carried out, typically on a much coarser CAA mesh.…”

Section: Numerical Examplementioning

confidence: 99%

“…This approach is accurate in cases where the flow grid is much finer than the acoustic grid but fails in cases where the flow grid is coarser than the acoustic grid. As a solution to this problem, we derived a cut cell approach and successfully applied it to the aeroacoustic computation of an axial fan . Similar investigations have been performed in Reference , where for both the flow and the acoustic field a finite volume scheme has been used.…”

Section: Introductionmentioning

confidence: 99%

“…The properties of the desired coupling scheme, or interpolation, are summed up as follows: An accurate and fast interpolation technique. An interpolation technique that handles special grids, for example, grids to resolve boundary layers. A method to compute accurate derivatives of the primary flow variables, such as pressure p , velocity u , density ρ, temperature T , and entropy s . A flexible algorithm that can be integrated into a standard product development cycle. A flexible algorithm that assembles different hybrid aeroacoustic source terms, for example, the divergence of the Lamb vector ∇·(((∇× u )× u ) ′ ) or the divergence of an entropy source

\nabla \cdot (T^{'} \nabla \overset{true‾}{s} - s^{'} \nabla \overset{true‾}{T})

. A conservative algorithm that transfers the desired amount of energy, defined by the aeroacoustic sources, from the flow discretization to the mesh of the acoustic simulation (see eg, Reference ;) is not discussed here. …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Aeroacoustic source term computation based on radial basis functions

Schoder

Roppert

Weitz

et al. 2020

Numerical Meth Engineering

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SUMMARY In low Mach number aeroacoustics, the known disparity of length scales makes it possible to apply well‐suited simulation models using different meshes for flow and acoustics. The workflow of these hybrid methodologies include performing an unsteady flow simulation, computing the acoustic sources, and simulating the acoustic field. Therefore, hybrid methods seek for robust and flexible procedures, providing a conservative mesh to mesh interpolation of the sources while ensuring high computational efficiency. We propose a highly specialized radial basis function interpolation for the challenges during hybrid simulations. First, the computationally efficient local radial basis function interpolation in conjunction with a connectivity‐based neighbor search technique is presented. Second, we discuss the computation of spatial derivatives based on radial basis functions. These derivatives are computed in a local‐global approach, using a Gaussian kernel on local point stencils. Third, radial basis function interpolation and derivatives are used to compute complex aeroacoustic source terms. These ingredients are necessary to provide flexible source term calculations that robustly connect flow and acoustics. Finally, the capabilities of the presented approach are shown in a numerical experiment with a co‐rotating vortex pair.

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Physical Models for Flow: Acoustic Interaction

Schoder

2021

Advances in Mathematical Fluid Mechanics

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Computational Aeroacoustics for Rotating Systems with Application to an Axial Fan

Cited by 24 publications

References 21 publications

Computational aeroacoustics of the EAA benchmark case of an axial fan

Computational aeroacoustics of the EAA benchmark case of an axial fan

Aeroacoustic source term computation based on radial basis functions

Physical Models for Flow: Acoustic Interaction

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