A High Order Overlapping Grid Method for CFD/CAA Coupling

Desquesnes, G.; Terracol, Marc; Manoha, Eric; Sagaut, Pierre

doi:10.2514/6.2005-2872

Cited by 5 publications

(6 citation statements)

References 9 publications

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“…Finally, the curvilinear extension strategy proposed by Visbal & Gaitonde (2002) has been retained to handle complex geometries. See Desquesnes et al (2006) for further details on the numerical method which has been extensively used for both aerodynamic and acoustic computations.…”

Section: Mathematical Model and Numerical Methodsmentioning

confidence: 99%

Numerical investigation of the tone noise mechanism over laminar airfoils

DESQUESNES,

TERRACOL,

SAGAUT

2007

J. Fluid Mech.

237

203

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This paper presents the first numerical investigation via direct numerical simulation of the tone noise phenomenon occurring in the flow past laminar airfoils. This phenomenon corresponds to the radiation of discrete acoustic tones in some specific flow conditions, and has received much attention since the 1970s, and several experimental studies have been carried out to identify and understand the underlying physical mechanisms. However, several points remain to be clarified in order to provide a complete explanation of its origin. The flow around a two-dimensional NACA0012 airfoil is considered in order to have a deeper understanding of the tone noise phenomenon. Consistently with previous experimental studies, it is shown that depending on the Reynolds number and angle of attack, two different types of acoustic spectrum are observed: one which exhibits a broadband contribution with a dominant frequency together with a sequence of regularly spaced discrete frequencies, while the other one is only characterized by a simple broadband contribution. The first configuration is typical of the tone noise phenomenon. The present work shows that in this case, the mean flow on the pressure side of the airfoil exhibits a separation bubble near the trailing edge and the main tone frequency is close to the most amplified frequency of the boundary layer. The mechanism proposed in previous works for the main tone generation – which implies the existence of a separation bubble at the pressure side – is therefore validated by numerical simulation. On the other hand, the analysis of the suction side boundary layer reveals that there is no separation and that the most amplified frequency is different from the main tonal one. However, the suction side boundary layer is highly receptive to the tone frequency. Finally, an original explanation for the existence of the secondary discrete frequencies observed in the radiated pressure spectrum is given. They are associated to a bifurcation of the airfoil wake from a symmetric to a non-symmetric vortex pattern. A possible explanation for the existence of this bifurcation is the interaction between the disturbances which are the most amplified by the suction side boundary layer and those originating in the forcing of the suction side flow by the main tone noise mechanism.

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Section: Mathematical Model and Numerical Methodsmentioning

confidence: 99%

Numerical investigation of the tone noise mechanism over laminar airfoils

DESQUESNES,

TERRACOL,

SAGAUT

2007

J. Fluid Mech.

237

203

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“…In this context, at ONERA [51][52][53][54][55][56][57], a high-order overlapping grid method for coupling Cartesian and curvilinear grids is developed in order to simulate aerodynamic noise. The overlapping grid method is based on Lagrange interpolating polynomials and a theoretical analysis of the interpolation operator is then carried out.…”

Section: The High-order Finite Differences Methodsmentioning

confidence: 99%

High accuracy flow simulations: Advances and challenges for future needs in aeronautics

2011

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“…Overlapping grids have been used in several fields of application, e.g. in computational aeroacoustics [25,26], conjugate heat transfer [27], simulation of moving bodies for aeronautical [28] and marine purposes [29]. For turbomachinery simulations with a structured solver, the overset grid approach is a way to account for complex technological e↵ects such as cavities and casing treatments [30,31].…”

Section: Introductionmentioning

confidence: 99%

“…This is even more critical in compressible LES since the resolved vortical, acoustic and entropic waves must accurately cross the overlapping interface. That is the reason why highorder overset grid methods have been recently developed for structured grids, for steady or moving interfaces [25,[32][33][34][35][36]. High-order discontinuous numerical methods, such as Discontinuous Galerkin, Flux Reconstruction and Spectral methods, have recently emerged in the CFD community, and dedicated high-order overset grid techniques had to be developed to preserve accuracy properties of such methods, e.g.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of a high-order unstructured overset grid method for compressible LES of turbomachinery

Laborderie

Duchaine

Gicquel

et al. 2018

Journal of Computational Physics

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Large-Eddy Simulation (LES) is recognized as a promising method for highfidelity flow predictions in turbomachinery applications. The presented approach consists of the coupling of several instances of the same LES unstructured solver through an overset grid method. A high-order interpolation, implemented within this coupling method, is introduced and evaluated on several test cases. It is shown to be third order accurate, to preserve the accuracy of various second and third order convective schemes and to ensure the continuity of di↵usive fluxes and subgrid scale tensors even in detrimental interface configurations. In this analysis, three types of spurious waves generated at the interface are identified. They are significantly reduced by the high-order interpolation at the interface. The latter having the same cost as the original lower order method, the high-order overset grid method appears as a promising alternative to be used in all the applications.

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A High Order Overlapping Grid Method for CFD/CAA Coupling

Cited by 5 publications

References 9 publications

Numerical investigation of the tone noise mechanism over laminar airfoils

Numerical investigation of the tone noise mechanism over laminar airfoils

High accuracy flow simulations: Advances and challenges for future needs in aeronautics

Numerical analysis of a high-order unstructured overset grid method for compressible LES of turbomachinery

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