The University of Southampton
University of Southampton Institutional Repository

The noise generation by a main landing gear door

The noise generation by a main landing gear door
The noise generation by a main landing gear door
Experimental measurements and numerical simulations were conducted on a simplified main landing gear model that consists of a leg-door, and a main strut in a parallel configuration. The effects of varying the leg-door angle of attack, and the gap distance between the two elements, were initially studied by two-dimensional and low-order numerical simulations, using the unsteady Reynolds-Averaged Navier-Stokes equations. The strut diameter was specified to the same diameter as a full-scale main landing gear, and simulated under a free-stream Mach number of 0.2, and a Reynolds number based on the cylinder diameter of 1:7 x 106. Further three-dimensional and high-order numerical simulations were conducted on models with a constant gap distance of 8.7% of the cylinder diameter. The high-order solver evaluates the three-dimensional Navier-Stokes equations in the full-conservation form, with the Zonal Detached-Eddy Simulation model. The fidelity of the numerical solver was improved in two parts. Firstly, an Eigenvalue analysis for a multiple-block environment was developed to optimise the combination of spatial and filtering schemes for maximum grid resolution that is numerically stable. Secondly, a grid quality metric, which correlates strongly to the solution accuracy, was developed. A validation database of experimental measurements on a tripped 26% scale interaction model, at a free-stream Mach number of 0.09, and a Reynolds number based on the cylinder diameter of 2 x 105, was developed at the 2:1 m x 1:5 m wind tunnel at the University of Southampton. The experimental and numerical results show that the wake generated by the interaction model is dominated by low frequencies that correspond to the vortex shedding modes of the cylinder, and the door. As the door angle is increased from 0 to 10.7 degrees, the intensity of the cylinder shedding mode decreased. The sound pressure levels of the radiated noise were calculated using the FW-H method. The dominant noise source is a compact dipole, which reduced in strength as the door angle was increased.
Fattah, Ryu
658d0694-d683-4839-89a0-b95601ebe365
Fattah, Ryu
658d0694-d683-4839-89a0-b95601ebe365
Hu, Zhiwei
dd985844-1e6b-44ba-9e1d-fa57c6c88d65

(2016) The noise generation by a main landing gear door. University of Southampton, Engineering and the Environment, Doctoral Thesis, 218pp.

Record type: Thesis (Doctoral)

Abstract

Experimental measurements and numerical simulations were conducted on a simplified main landing gear model that consists of a leg-door, and a main strut in a parallel configuration. The effects of varying the leg-door angle of attack, and the gap distance between the two elements, were initially studied by two-dimensional and low-order numerical simulations, using the unsteady Reynolds-Averaged Navier-Stokes equations. The strut diameter was specified to the same diameter as a full-scale main landing gear, and simulated under a free-stream Mach number of 0.2, and a Reynolds number based on the cylinder diameter of 1:7 x 106. Further three-dimensional and high-order numerical simulations were conducted on models with a constant gap distance of 8.7% of the cylinder diameter. The high-order solver evaluates the three-dimensional Navier-Stokes equations in the full-conservation form, with the Zonal Detached-Eddy Simulation model. The fidelity of the numerical solver was improved in two parts. Firstly, an Eigenvalue analysis for a multiple-block environment was developed to optimise the combination of spatial and filtering schemes for maximum grid resolution that is numerically stable. Secondly, a grid quality metric, which correlates strongly to the solution accuracy, was developed. A validation database of experimental measurements on a tripped 26% scale interaction model, at a free-stream Mach number of 0.09, and a Reynolds number based on the cylinder diameter of 2 x 105, was developed at the 2:1 m x 1:5 m wind tunnel at the University of Southampton. The experimental and numerical results show that the wake generated by the interaction model is dominated by low frequencies that correspond to the vortex shedding modes of the cylinder, and the door. As the door angle is increased from 0 to 10.7 degrees, the intensity of the cylinder shedding mode decreased. The sound pressure levels of the radiated noise were calculated using the FW-H method. The dominant noise source is a compact dipole, which reduced in strength as the door angle was increased.

PDF
thesis.pdf - Other
Download (44MB)

More information

Published date: March 2016
Organisations: University of Southampton, Aerodynamics & Flight Mechanics Group

Identifiers

Local EPrints ID: 390837
URI: http://eprints.soton.ac.uk/id/eprint/390837
PURE UUID: 86be2ce8-421c-43eb-867e-2d37609be5ef

Catalogue record

Date deposited: 05 Apr 2016 11:19
Last modified: 17 Jul 2017 19:25

Export record

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×