Progress in Direct Noise Computation

Bailly, Christophe; Bogey, Christophe; Marsden, Olivier

doi:10.1260/1475-4738.9.3.31

Cited by 15 publications

(15 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…OMPUTATIONAL aeroacoustics (CAA) has been applied successfully to various aerodynamic noise problems. For example, noise generated by high-speed jet flow 1 has been been successfully tackled via the direct noise computation approach 1,2 (i.e. direct computation of full compressible Navier-Stokes equations with high-resolution numerical methods).…”

Section: Introductionmentioning

confidence: 99%

Computation of Aerodynamic Sound around Complex Stationary and Moving Bodies

Seo

Mittal

2011

49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

View full text Add to dashboard Cite

Aerodynamic sound generation at low Mach numbers around complex stationary and moving bodies is computed directly with an immersed-boundary method-based hybrid approach. The complex flow field is solved by the immersed-boundary incompressible Navier-Stokes flow solver and the sound generation and propagation are computed by the linearized perturbed compressible equations with a high-order immersed boundary method, on a non-body conformal Cartesian grid. The present method is applied to the prediction of noise generated by turbulent flow over a tandem cylinder arrangement as well as a rudimentary landing gear noise. For a moving body problem, the aerodynamic sound generated by modeled flapping wings is computed.

show abstract

Section: Introductionmentioning

confidence: 99%

Computation of Aerodynamic Sound around Complex Stationary and Moving Bodies

Seo

Mittal

2011

49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

View full text Add to dashboard Cite

show abstract

“…For flows at high Reynolds numbers, the direct computation of the aerodynamic noise from the Navier-Stokes equations requires accurate numerical methods to properly compute both the small turbulent motions and the low-frequency sound waves in the radiated pressure field. [1][2][3] To meet these requirements, in addition to high-order discretization schemes, locally refined meshes are needed to capture the turbulent eddies generating noise. 4 For aeroacoustic simulations performed on multiblock structured grids, the computational domain is usually divided into subdomains composed of conforming grids characterized by a full point-matching distribution at the block interface, as shown in Figure 1A.…”

Section: Introductionmentioning

confidence: 99%

“…For flows at high Reynolds numbers, the direct computation of the aerodynamic noise from the Navier‐Stokes equations requires accurate numerical methods to properly compute both the small turbulent motions and the low‐frequency sound waves in the radiated pressure field . To meet these requirements, in addition to high‐order discretization schemes, locally refined meshes are needed to capture the turbulent eddies generating noise …”

Section: Introductionmentioning

confidence: 99%

A technique of flux reconstruction at the interfaces of nonconforming grids for aeroacoustic simulations

Bras

Deniau

Bogey

2019

Numerical Methods in Fluids

Self Cite

View full text Add to dashboard Cite

Summary A flux reconstruction technique is presented to perform aeroacoustic computations using implicit high‐order spatial schemes on multiblock structured grids with nonconforming interfaces. The use of such grids, with mesh spacing discontinuities across the block interfaces, eases local mesh refinements, simplifies the mesh generation process, and thus facilitates the computation of turbulent flows. In this work, the spatial discretization consists of sixth‐order finite‐volume implicit schemes with low‐dispersion and low‐dissipation properties. The flux reconstruction is based on the combination of noncentered schemes with local interpolations to define ghost cells and compute flux values at the grid interfaces. The flow variables in the ghost cells are calculated from the flow field in the grid cells using a meshless interpolation with radial basis functions. In this study, the flux reconstruction is applied to both plane and curved nonconforming interfaces. The performance of the method is first evaluated by performing two‐dimensional simulations of the propagation of an acoustic pulse and of the convection of a vortex on Cartesian and wavy grids. No significant spurious noise is produced at the grid interfaces. The applicability of the flux reconstruction to a three‐dimensional computation is then demonstrated by simulating a jet at a Mach number of 0.9 and a diameter‐based Reynolds number of 4×105 on a Cartesian grid. The nonconforming grid interface located downstream of the jet potential core does not appreciably affect the flow development and the jet sound field, while reducing the number of mesh points by a factor of approximately two.

show abstract

“…While the addition of a certain amount of compressibility has made the calculation of incompressible flows easier without taking into account the consequent acoustic field, the inclusion of compressibility in the flow formulation has been a drawback for calculating acoustics when dealing with low speed flows. The conservative compressible flow equations are considered the complete representation of the aeroacoustic problem because they describe directly all flow and acoustic scales without any need for modeling, which in terms of Computational Fluid Dynamics (CFD) is called Direct Numerical Simulation (DNS), [5], and in acoustics is referred as Direct Noise Computation (DNC), [6]. However, as stated above, this formulation performs poorly for Mach numbers tending to zero due to the huge difference between flow velocity and wave propagation speed, which causes convergence problems.…”

Section: Introductionmentioning

confidence: 99%

Unified solver for fluid dynamics and aeroacoustics in isentropic gas flows

Pont

Codina

Baiges

et al. 2018

Journal of Computational Physics

View full text Add to dashboard Cite

The propagation of acoustic waves is a physical phenomenon which can only be described taking into account the compressibility of the medium. The high computational cost of solving numerically the fully compressible Navier-Stokes equations, together with the poor performance of most numerical formulations for compressible flow in the low Mach number regime, has led to the necessity for more affordable numerical models for Computational Aeroacoustics. For low Mach number subsonic flows with neither shocks nor thermal coupling, both flow dynamics and wave propagation can be considered isentropic. Therefore, a joint isentropic formulation for flow and aeroacoustics can be devised which avoids the need for segregating flow and acoustic scales. Under these assumptions density and pressure fluctuations are directly proportional, and a two field velocity-pressure compressible formulation can be derived as an extension of an incompressible solver. On the other hand, the linear system of equations which arises from the proposed isentropic formulation is better conditioned than the homologous incompressible one due to the presence of a pressure perturbation term. Similarly to other compressible formulations the prescription of boundary conditions will have to deal with the backscattering of acoustic waves. In this sense, a separated imposition of boundary conditions for flow and acoustic scales which allows the evacuation of waves through Dirichlet boundaries

show abstract

Progress in Direct Noise Computation

Cited by 15 publications

References 52 publications

Computation of Aerodynamic Sound around Complex Stationary and Moving Bodies

Computation of Aerodynamic Sound around Complex Stationary and Moving Bodies

A technique of flux reconstruction at the interfaces of nonconforming grids for aeroacoustic simulations

Unified solver for fluid dynamics and aeroacoustics in isentropic gas flows

Contact Info

Product

Resources

About