Proceedings ArticleDOI
Towards Numerical Aircraft Noise Certification: Analysis of a Full-Scale Landing Gear in Fly-Over Configuration
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In this paper, a numerical procedure for the prediction of aircraft noise certi cation metrics starting from the aircraft trajectory is described, which is applied to the nose landing gear of a Gulfstream business jet.Abstract:
This paper describes a numerical procedure for the prediction of aircraft noise certi cation metrics starting from the aircraft trajectory. The procedure is applied to the nose landing gear of a Gulfstream business jet. The numerical core of the procedure is a hybrid aeroacoustic method based on a lattice Boltzmann ow simulation and a Ffowcs-Williams & Hawkings noise propagation computation. The hybrid method is initially validated by computing the noise generated by a geometrically simpli ed model of the same landing gear installed on a at plate and comparing wall pressure and fareld noise spectra with wind-tunnel measurements. The same numerical method and a similar discretized model are then employed to compute the unsteady ow eld past the real landing gear deployed under the aircraft. The upstream ow conditions are the same occurring during a ight along a \nominally" constant descent trajectory at the nearest point to the ground microphone. Comparisons between the predicted noise levels and the measured ones during a ight test, with only the nose landing gear deployed and other airframe and engine sources kept at their admissible minimum, are in good agreement.read more
Citations
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Journal ArticleDOI
Aircraft noise prediction
TL;DR: It is contended that the field of aircraft noise prediction has not yet reached a sufficient level of maturity, in particular, some parametric effects cannot be investigated, issues of accuracy are not currently addressed, and validation standards are still lacking.
Proceedings ArticleDOI
Towards Full Aircraft Airframe Noise Prediction: Lattice Boltzmann Simulations
TL;DR: In this paper, the authors used Exa Corporation's lattice Boltzmann PowerFLOW solver to perform time-dependent simulations of the flow field associated with this high-fidelity aircraft model.
Journal ArticleDOI
Lattice–Boltzmann Aeroacoustic Analysis of the LAGOON Landing-Gear Configuration
TL;DR: In this article, the authors used a hybrid approach in which the flowfield is provided by a lattice-Boltzmann simulation, and the noise radiation is computed using the Ffowcs-Williams-Hawkings analogy.
Journal ArticleDOI
Facing rim cavities fluctuation modes
TL;DR: In this article, a parametric study of the cavity mode properties is carried out by varying the distance between the wheels of two opposite wheels, and the effects due to the presence of the axle are investigated by removing the axle from the two-wheel assembly.
Journal ArticleDOI
Numerical analysis of fan noise for the NOVA boundary-layer ingestion configuration
TL;DR: In this paper, the effects of the turbulent flow developing over a fuselage on fan noise for BLI embedded propulsion systems were investigated by solving the explicit, transient and compressible lattice Boltzmann equation implemented in the high-fidelity CFD/CAA solver Simulia PowerFLOW®.
References
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Victor Yakhot,Steven A. Orszag +1 more
TL;DR: In this article, a dynamic renormalization group (RNG) method for hydrodynamic turbulence was developed, which uses dynamic scaling and invariance together with iterated perturbation methods, allowing us to evaluate transport coefficients and transport equations for the large scale (slow) modes.
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Lattice-Gas Automata for the Navier-Stokes Equation
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Renormalization-group analysis of turbulence.
Victor Yakhot,Steven A. Orszag +1 more
TL;DR: Using renormalization-group methods and the postulated equivalence between the inertial-range structures of turbulent flows satisfying initial and boundary conditions and of flows driven by a random force, the Kolmogorov constant and Batchelor constant are evaluated and the skewness factor and power-law exponent are evaluated.