Aeroacoustic Study on a Simplified Nose Landing Gear

2012 ◽  
Vol 184-185 ◽  
pp. 18-23 ◽  
Author(s):  
Shuang Li Long ◽  
Hong Nie ◽  
Xin Xu
Keyword(s):  
Simulation Analysis ◽  
Sound Field ◽  
Low Noise ◽  
Landing Gear ◽  
Broadband Noise ◽  
Detached Eddy Simulation ◽  
Gear Design ◽  
Aeroacoustic Noise ◽  
Eddy Simulation ◽  
Landing Gear Noise

Simulation analysis and experiment research are performed on the aeroacoustic noise of a landing gear component in this paper. Detached Eddy Simulation (DES) is used to produce the flow field of the model. The Ffowcs-Williams/Hawkings (FW-H) equation is used to calculate the acoustic field. The sound field radiated from the model is measured in the acoustic wind tunnel. A comparison shows that the simulation results agree well with the experiment results under the acoustic far field condition. The results show that the noise radiated from the model is broadband noise. The directivity of the noise source is like a type of dipole. The wheel is the largest contributor and the strut is the least contributor to the landing gear noise. The results can provide some reference for low noise landing gear design.

Simulation and Experiment on Landing Gear Component Noise

2012 ◽  
Vol 170-173 ◽  
pp. 3454-3459
Author(s):  
Long Shuang Li ◽  
Hong Nie ◽  
Xin Xu
Keyword(s):  
Shock Absorber ◽  
Simulation Analysis ◽  
Sound Field ◽  
Landing Gear ◽  
Broadband Noise ◽  
Detached Eddy Simulation ◽  
Aeroacoustic Noise ◽  
Eddy Simulation ◽  
Total Noise ◽  
Simulation And Experiment

Simulation analysis and experiment research are performed on the aeroacoustic noise of a landing gear component in this paper. Detached Eddy Simulation (DES) is used to produce the flow field of the model. The Ffowcs-Williams/Hawkings (FW-H) equation is used to calculate the acoustic field. The sound field radiated from the model is measured in the acoustic wind tunnel. A comparison shows that the simulation results agree well with the experiment results under the acoustic far field condition. The results show that the noise radiated from the model is broadband noise. The directivity of the noise source is like a type of dipole. The location between shock absorber and strut, shock absorber and bogie can induce the interaction noise which is presented by two energy peaks in the spectra. The shock absorber and the bogie is the main contributor while the strut is the least contributor to the total noise.

Detached-Eddy Simulations Over a Simplified Landing Gear

2002 ◽  
Vol 124 (2) ◽  
pp. 413-423 ◽  
Author(s):  
L. S. Hedges ◽  
A. K. Travin ◽  
P. R. Spalart
Keyword(s):  
Stokes Equations ◽  
Separated Flow ◽  
Flow Fields ◽  
Equation Model ◽  
Landing Gear ◽  
Navier Stokes ◽  
Detached Eddy Simulation ◽  
Navier Stokes Equations ◽  
Instantaneous Flow ◽  
Eddy Simulation

The flow around a generic airliner landing-gear truck is calculated using the methods of Detached-Eddy Simulation, and of Unsteady Reynolds-Averaged Navier-Stokes Equations, with the Spalart-Allmaras one-equation model. The two simulations have identical numerics, using a multi-block structured grid with about 2.5 million points. The Reynolds number is 6×105. Comparison to the experiment of Lazos shows that the simulations predict the pressure on the wheels accurately for such a massively separated flow with strong interference. DES performs somewhat better than URANS. Drag and lift are not predicted as well. The time-averaged and instantaneous flow fields are studied, particularly to determine their suitability for the physics-based prediction of noise. The two time-averaged flow fields are similar, though the DES shows more turbulence intensity overall. The instantaneous flow fields are very dissimilar. DES develops a much wider range of unsteady scales of motion and appears promising for noise prediction, up to some frequency limit.

scholarly journals High-fidelity simulations of unsteady civil aircraft aerodynamics: stakes and perspectives. Application of zonal detached eddy simulation

2014 ◽  
Vol 372 (2022) ◽  
pp. 20130325 ◽  
Author(s):  
Sébastien Deck ◽  
Fabien Gand ◽  
Vincent Brunet ◽  
Saloua Ben Khelil
Keyword(s):  
Turbulent Flows ◽  
Hybrid Methods ◽  
Landing Gear ◽  
High Fidelity ◽  
Detached Eddy Simulation ◽  
High Lift ◽  
Eddy Simulation ◽  
Civil Aircraft ◽  
Aircraft Aerodynamics ◽  
Transonic Buffet

This paper provides an up-to-date survey of the use of zonal detached eddy simulations (ZDES) for unsteady civil aircraft applications as a reflection on the stakes and perspectives of the use of hybrid methods in the framework of industrial aerodynamics. The issue of zonal or non-zonal treatment of turbulent flows for engineering applications is discussed. The ZDES method used in this article and based on a fluid problem-dependent zonalization is briefly presented. Some recent landmark achievements for conditions all over the flight envelope are presented, including low-speed (aeroacoustics of high-lift devices and landing gear), cruising (engine–airframe interactions), propulsive jets and off-design (transonic buffet and dive manoeuvres) applications. The implications of such results and remaining challenges in a more global framework are further discussed.

scholarly journals Zonal Detached Eddy Simulation of a simplified nose landing-gear for flow and noise predictions using an unstructured Navier-Stokes solver

2017 ◽  
Vol 405 ◽  
pp. 86-111 ◽  
Author(s):  
Fernando de la Puente Cerezo ◽  
Laurent Sanders ◽  
François Vuillot ◽  
Philippe Druault ◽  
Eric Manoha
Keyword(s):  
Landing Gear ◽  
Navier Stokes ◽  
Detached Eddy Simulation ◽  
Eddy Simulation

scholarly journals Research on Aerodynamic Noise Reduction for High-Speed Trains

2016 ◽  
Vol 2016 ◽  
pp. 1-21 ◽  
Author(s):  
Yadong Zhang ◽  
Jiye Zhang ◽  
Tian Li ◽  
Liang Zhang ◽  
Weihua Zhang
Keyword(s):  
Noise Reduction ◽  
High Speed ◽  
Low Noise ◽  
Broadband Noise ◽  
Full Scale ◽  
Noise Model ◽  
Aerodynamic Noise ◽  
High Speed Train ◽  
Detached Eddy Simulation ◽  
Noise Sources

A broadband noise source model based on Lighthill’s acoustic theory was used to perform numerical simulations of the aerodynamic noise sources for a high-speed train. The near-field unsteady flow around a high-speed train was analysed based on a delayed detached-eddy simulation (DDES) using the finite volume method with high-order difference schemes. The far-field aerodynamic noise from a high-speed train was predicted using a computational fluid dynamics (CFD)/Ffowcs Williams-Hawkings (FW-H) acoustic analogy. An analysis of noise reduction methods based on the main noise sources was performed. An aerodynamic noise model for a full-scale high-speed train, including three coaches with six bogies, two inter-coach spacings, two windscreen wipers, and two pantographs, was established. Several low-noise design improvements for the high-speed train were identified, based primarily on the main noise sources; these improvements included the choice of the knuckle-downstream or knuckle-upstream pantograph orientation as well as different pantograph fairing structures, pantograph fairing installation positions, pantograph lifting configurations, inter-coach spacings, and bogie skirt boards. Based on the analysis, we designed a low-noise structure for a full-scale high-speed train with an average sound pressure level (SPL) 3.2 dB(A) lower than that of the original train. Thus, the noise reduction design goal was achieved. In addition, the accuracy of the aerodynamic noise calculation method was demonstrated via experimental wind tunnel tests.

scholarly journals Zonal Detached Eddy Simulation of the Fan-OGV Stage of a Modern Turbofan Engine

2020 ◽  
Author(s):  
Benjamin François ◽  
Raphaël Barrier ◽  
Cyril Polacsek
Keyword(s):  
Statistical Convergence ◽  
Hybrid Approach ◽  
Broadband Noise ◽  
Detached Eddy Simulation ◽  
Turbofan Engine ◽  
The Core ◽  
Eddy Simulation ◽  
Gap Flow ◽  
Radial Profiles ◽  
Radial Evolution

Abstract The present article deals with the Zonal Detached Eddy Simulation of the fan module of a modern turbofan engine. The fan module, tested at the AneCom facility, is equipped with rotating fan blades and stationary outlet guide vanes (OGV). The simulation was performed to capture the interaction of the turbulent fan wakes with the OGV walls. The final goal of this simulation is the prediction of the associated broadband noise, not adressed here. In this paper, only the aerodynamic aspects are treated. The simulation relies on a hybrid RANS/LES approach with a zonal strategy: the core airflow is treated in RANS while the bypass airflow is solved with the hybrid approach. Mesh criteria meeting both RANS/LES and acoustic requirements were fulfilled, leading to a mesh of 380 million cells. The simulation was performed during five revolutions and statistical convergence was reached. Inspections of the flow-fields highlight a consistent behaviour of the shielding function (border between RANS and LES solving areas) around the blade walls, at the trailing-edge and in the tip gap flow areas. Comparisons with performance and hot-wire measurements are also presented. Aerodynamic performance and radial evolution of averaged velocities on a plane in-between the fan and the OGV are well retrieved, both in shape and levels. For the turbulent quantities, the shape of the radial profiles are close to the measurements, with much better accuracy in the upper region compared to the RANS solution.

scholarly journals Aeroacoustic Source Separation on a Full Scale Nose Landing Gear Featuring Combinations of Low Noise Technologies

2015 ◽  
Author(s):  
Eleonora Neri ◽  
John Kennedy ◽  
Gareth J. Bennett
Keyword(s):  
Noise Reduction ◽  
Low Noise ◽  
Landing Gear ◽  
Full Scale ◽  
Commercial Aircraft ◽  
Noise Sources ◽  
Gear Noise ◽  
Aircraft Landing ◽  
Total Noise ◽  
Landing Gear Noise

The reduction of noise generated by aircraft at take-off and approach is crucial in the design of new commercial aircraft. Landing gear noise is significant contribution to the total noise sources during approach. The noise is generated by the interaction between the non-aerodynamic components of the landing gear and the flow, which leads to turbulence generated noise. This research presents results from the European Clean Sky funded ALLEGRA project. The project investigated a full-scale Nose Landing Gear (NLG) model featuring the belly fuselage, bay cavity and hydraulic dressing. A number of low noise treatments were applied to the NLG model including a ramp door spoiler, a wheel axel wind shield, wheel hub caps and perforated fairings. Over 250 far field sensors were deployed in a number of microphone arrays. Since technologies were tested both in isolation and in combination the additive effects of the technologies can be assessed. This study describes the different techniques used to quantify the contribution of each technology to the global noise reduction. The noise reduction technologies will be assessed as a function of frequency range and through beamforming techniques such as source deletion.

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