| 1. |
- Hoffman, Johan, et al.
(författare)
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Computation of slat noise sources using adaptive FEM and lighthill's analogy
- 2013
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Ingår i: 19th AIAA/CEAS Aeroacoustics Conference.
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Konferensbidrag (refereegranskat)abstract
- This is a summary of preliminary results from simulations with the 30P30N high-lift device. We used the General Galerkin finite element method (G2), where no explicit subgrid model is used, and where the computational mesh is adaptively refined with respect to a posteriori error estimates for a quantity of interest. The mesh is fully unstructured and the solutions are time-resolved, which are key ingredients for solving challenging industrial applications in the field of aeroacoustics. We present preliminary results containing time-averaged quantities and snapshots of unsteady quantities, all reasonably agreeing with previous computational efforts. One important finding is that the use of adaptively generated meshes seems to be a more effcient way of computing aeroacoustic sources than by using "handmade" meshes.
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| 2. |
- Hoffman, Johan, et al.
(författare)
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Unicorn : Parallel adaptive finite element simulation of turbulent flow and fluid-structure interaction for deforming domains and complex geometry
- 2013
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Ingår i: Computers & Fluids. - : Elsevier BV. - 0045-7930 .- 1879-0747. ; 80:SI, s. 310-319
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Tidskriftsartikel (refereegranskat)abstract
- We present a framework for adaptive finite element computation of turbulent flow and fluid structure interaction, with focus on general algorithms that allow for complex geometry and deforming domains. We give basic models and finite element discretization methods, adaptive algorithms and strategies for efficient parallel implementation. To illustrate the capabilities of the computational framework, we show a number of application examples from aerodynamics, aero-acoustics, biomedicine and geophysics. The computational tools are free to download open source as Unicorn, and as a high performance branch of the finite element problem solving environment DOLFIN, both part of the FEniCS project.
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| 3. |
- Jansson, Johan, et al.
(författare)
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Adaptive stabilized finite element framework for simulation of vocal fold turbulent fluid-structure interaction
- 2013
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Ingår i: Proceedings of Meetings on Acoustics. - : Acoustical Society of America (ASA). ; , s. 1-9
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Konferensbidrag (refereegranskat)abstract
- As a step toward building a more complete model of voice production mechanics, we assess the feasibility of a fluid-structure simulation of the vocal fold mechanics in the Unicorn incompressible Unified Continuum framework. The Unicorn framework consists of conservation equations for mass and momentum, a phase function selecting solid or fluid constitutive laws, a convection equation for the phase function and moving mesh methods for tracking the interface, and discretization through an adaptive stabilized finite element method. The framework has been validated for turbulent flow for both low and high Reynolds numbers and has the following features: implicit turbulence modeling (turbulent dissipation only occurs through numerical stabilization), goal-oriented mesh adaptivity, strong, implicit fluid-structure coupling and good scaling on massively parallel computers. We have applied the framework for turbulent fluid-structure interaction simulation of vocal folds, and present initial results. Acoustic quantities have been extracted from the framework in the setting of an investigation of a configuration approximating an exhaust system with turbulent flow around a flexible triangular steel plate in a circular duct. We present some results of the investigation as well as results of the framework applied to other problems.
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| 4. |
- Vilela De Abreu, Rodrigo, et al.
(författare)
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Towards the development of adaptive finite element methods for internal flow aeroacoustics
- 2013
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Ingår i: 19th AIAA/CEAS Aeroacoustics Conference. - 9781624102134
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Konferensbidrag (refereegranskat)abstract
- We report the latest results obtained in the development of an adaptive finite element method for computational aeroacoustics (CAA). The new methodology is based on the General Galerkin (G2) method, which has been successfully used for the computation of incompressible, turbulent flow. Here, we simulate the flow past an in-duct mixer plate and compare the results with available experimental data. The comparisons include mean velocity profiles and frequency content of the turbulent signal. No direct simulation of sound or sound wave propagation has been performed; instead, simple analogy arguments have been used to extract acoustic results from incompressible simulations by assuming a direct correlation between the computed pressure drop signal and the sound at the far field. We were able to reproduce the sound signal from experiments with our incompressible simulation and our results compared well with both the level and the broadband frequency peak of the measured sound. We suggest that the methodology presented here is mainly suitable for the prediction of sound in low Mach number pipe flows.
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