Article
Acoustics
Lican Wang, Rongqian Chen, Yancheng You, Zhaohuan Wang, Qiaochu Song
Summary: An efficient radiation and scattering prediction method based on the convective FW-H equation and ESM is proposed, using ESM-I and ESM-S for predicting incident acoustic pressure and acoustic pressure gradient, with the use of an energy-based singular value decomposition method. The methodology is suggested to be suitable for situations in different dimensions with the introduction of moving-medium effects, examined through analytical solutions for point sources and scattered bodies.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Chemistry, Multidisciplinary
Haotian Qi, Ping Wang, Linsong Jiang, Yang Zhang
Summary: A numerical method based on RANS equations and a high-efficiency trim model is developed to simulate the aerodynamics of a coaxial rotor. The study shows that the special noise characteristics of the coaxial rotor are mainly caused by the noise superposition of the twin rotors and the unsteady loads of aerodynamic interaction.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Aerospace
W. C. P. van der Velden, G. Romani, D. Casalino
Summary: This study applies a Lattice-Boltzmann based solver to perform scale-resolving unsteady flow simulations on a full-scale helicopter main rotor in forward flight for the first time. The validation is conducted by comparing the simulation results with reference wind tunnel data, providing insights into aerodynamic and acoustic quantities for different rotor advance ratios. Additionally, digital helicopter noise certification is achieved by calculating the ground noise map for a helicopter in landing condition.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Acoustics
Tao Yang, Xi Chen, Qijun Zhao, Yan Ding
Summary: Based on the Linearized Euler Equations (LEE) and the Computational Fluid Dynamics (CFD) technique, the propagation characteristics of helicopter rotor High-Speed Impulsive (HSI) noise in non-uniform flowfield are simulated and analyzed. A Hybrid Computational Aeroacoustics (HCAA) method is developed to solve the sound field of the rotor. The effects of the shear layer on HSI noise propagation and the characteristics in different flow conditions are studied.
Article
Engineering, Aerospace
Morteza Monfaredi, Varvara Asouti, Xenofon Trompoukis, Konstantinos Tsiakas, Kyriakos Giannakoglou
Summary: This paper presents a continuous adjoint-based aeroacoustic optimization method for the design of aero-engine intakes with an axisymmetric geometry. The method parameterizes the generatrix of the intake's lips and minimizes the energy in the sound pressure spectrum at the blade passing frequency. The method avoids the numerical solution of the unsteady flow equations and the high cost of optimization.
Article
Engineering, Marine
Savas Sezen, Taner Cosgun, Ahmet Yurtseven, Mehmet Atlar
Summary: This study focuses on the impact of grid resolution on the hydroacoustic performance of a propeller, as well as the contribution of tip vortex to the overall acoustic pressure. Results show that inadequate grid resolution in numerical simulations leads to unphysical numerical noise, affecting the prediction of overall acoustic pressures.
Article
Engineering, Aerospace
Wei Bian, Guoqing Zhao, Xi Chen, Bo Wang, Qijun Zhao
Summary: This study establishes numerical simulation methods for unsteady vortex field of helicopter rotor with high resolution and low dissipation using moving-embedded grid and Navier-Stokes equations. The TENO8-AA primitive variables reconstruction schemes are developed based on ENO-like candidate stencil selection strategy, reducing dissipation and dispersion errors and improving spectral properties. The results demonstrate that the TENO8-AA scheme can capture the blade tip vortex trajectory and improve the simulation accuracy of thrust coefficient. The analyses for BVI and aeroacoustic characteristics of Operational Loads Survey (OLS) rotor reveal different forms of interaction mechanisms, achieving significant reduction in acoustic pressure peak prediction error.
CHINESE JOURNAL OF AERONAUTICS
(2023)
Article
Engineering, Mechanical
Stavros Vouros, Nikolaos D. Polyzos, Ioannis Goulos, Vassilios Pachidis
Summary: The research explores the impact of combined variable rotor speed and active blade twist helicopter technologies on aeroacoustics, environment, and ground noise, optimizing for noise reduction and NOx emissions. By using an integrated approach and advanced modeling, significant reductions in ground noise and emissions have been achieved.
JOURNAL OF FLUIDS AND STRUCTURES
(2021)
Article
Engineering, Aerospace
Andre F. P. Ribeiro, Mehdi R. Khorrami, Ryan Ferris, Benedikt Koenig, Patricio A. Ravetta
Summary: This paper presents the commonly used approach of using integral solutions to assess far-field acoustic behavior from airframe noise simulations based on the FW-H formulation. It discusses the limitations of the solid surface and permeable surface methods and provides guidelines for proper calculations. Results for various configurations are shown to highlight the accuracy differences and the need for additional steps to extract correct far-field noise spectra.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Mechanical
Yuanjun Dai, Yiran An, Zhi Li, Qunfeng Zhang
Summary: This study investigates the noise generation and radiation in the inlet duct caused by shock and boundary layer interaction using non-linear acoustic solver and FW-H equation. The results show good agreement with experimental data, and it is observed that the oscillation of inner shocks determines the overall sound pressure level of the far-field noise.
ACTA MECHANICA SINICA
(2022)
Article
Green & Sustainable Science & Technology
Wladyslaw Marek Hamiga, Wojciech Bronislaw Ciesielka
Summary: This study focuses on the aerodynamic and aeroacoustic characteristics of identical truck column models, validating the results through calculations and field tests, which can serve as a reference for the development of intelligent transport systems and intelligent environmental management systems.
Article
Energy & Fuels
Wladyslaw Marek Hamiga, Wojciech Bronislaw Ciesielka
Summary: In the past decade, there has been a significant interest in both conventional and unconventional energy issues. This interest has extended to road transport and efforts to minimize fuel or energy consumption and environmental impact. This study presents original tests on aerodynamics and aeroacoustics of mixed vehicle columns, using computational fluid dynamics methods and turbulence models. The results show that grouping vehicles optimally and maintaining distances can lead to energy savings and reduced harmful emissions.
Article
Engineering, Aerospace
Bo Wang, Chenkai Cao, Qijun Zhao, Xin Yuan, Zheng Zhu
Summary: A numerical method combining CFD method and FW-H equations is used to predict the acoustic characteristics of coaxial rotor in different flight states. The simulation results show significant unsteady characteristics in the coaxial rotor flowfield, leading to dominant loading noise in hovering state and unique features in HSI noise during high-speed forward flight. The study also reveals the counter-rotating characteristics of upper and lower rotors, as well as the symmetrical distribution of noise radiation intensity in forward direction for coaxial rotor during high-speed flight.
INTERNATIONAL JOURNAL OF AERONAUTICAL AND SPACE SCIENCES
(2021)
Article
Engineering, Aerospace
Junhao Zhang, Pinqi Xia, Inderjit Chopra
Summary: This study investigates the aeromechanical stability of a bearingless rotor helicopter with double-swept blades, showing that the double-swept blade can increase the critical rotational speed in ground contact conditions and improve stability in forward flight. Additionally, the outer droop angle can stabilize the rotor/fuselage coupled system, and parameters related to the outer swept-back part have a greater influence on stability.
JOURNAL OF AIRCRAFT
(2021)
Article
Engineering, Aerospace
Sueleyman Demir, Mustafa Kurt, Temel Kotil
Summary: Topology optimization is widely used in additive manufacturing. This study proposes a topology optimization method for designing fatigue critical parts, aiming to reduce the weight of the structure. The results show an 18% increase in weight compared to the classical method, but an overall weight reduction of 34% through fatigue-based optimization.
JOURNAL OF AEROSPACE ENGINEERING
(2022)