Predicting Far-Field Noise Generated by a Landing Gear Using Multiple Two-Dimensional Simulations

Sultan Alqash,Sharvari Dhote,Kamran Behdinan

doi:10.3390/app9214485

Sultan Alqash, Sharvari Dhote + Show 1 more

Open Access

https://doi.org/10.3390/app9214485

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Journal: Applied sciences	Publication Date: Oct 23, 2019
Citations: 3	License type: CC BY 4.0

Affiliation: University of Toronto, Taibah University

Abstract

In this paper, a new approach is proposed to predict the far-field noise of a landing gear (LG) based on near-field flow data obtained from multiple two-dimensional (2D) simulations. The LG consists of many bluff bodies with various shapes and sizes. The analysis begins with dividing the LG structure into multiple 2D cross-sections (C-Ss) representing different configurations. The C-Ss locations are selected based on the number of components, sizes, and geometric complexities. The 2D Computational Fluid Dynamics (CFD) analysis for each C-S is carried out first to obtain the acoustic source data. The Ffowcs Williams and Hawkings acoustic analogy (FW-H) is then used to predict the far-field noise. To compensate for the third dimension, a source correlation length (SCL) is assumed based on a perfectly correlated flow. The overall noise of the LG is calculated as the incoherent sum of the predicted noise from all C-Ss. Flow over a circular cylinder is then studied to examine the effect of the 2D CFD results on the predicted noise. The results are in good agreement with reported experimental and numerical data. However, the Strouhal number (St) is over-predicted. The proposed approach provides a reasonable estimation of the LG far-field noise at a low computational cost. Thus, it has the potential to be used as a quick tool to predict the far-field noise from an LG during the design stage.

Highlights

Aircraft noise has been recognized as a significant environmental problem since the 1950s.due to the development of quieter engines, Airframe Noise (AFN) has become the dominant source of noise during the landing phase [1]
It is noted that the Overall Sound Pressure Level (OASPL) value with source correlation length (SCL) = 5.0D for all the three mesh sizes is in good agreement with the measured experimental data obtained by Revell et al [29]
This paper presented a new approach to predict the landing gear (LG) far-field noise based on near-field flow

Summary

Introduction

Due to the development of quieter engines, Airframe Noise (AFN) has become the dominant source of noise during the landing phase [1]. The landing gears (LGs) are considered one of the main sources of noise emitted during the approach-to-land phase of flight. In the last 40 years, aeroacoustics became an important research field to accelerate AFN reduction. Both U.S and European governments have set stringent targets to minimize the AFN [2]. To fulfill high design standards, new aircraft designs demand efficient AFN prediction techniques to assess the noise impact. Multi-fidelity approaches are required to enable efficient and accurate aircraft noise assessment at different design stages [3]. The accuracy of noise prediction techniques is attributed to various factors, including turbulence modelling and/or acoustic analogy implementation and boundary conditions [4,5,6,7,8,9]

Results

Discussion

Conclusion