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Journal articles on the topic 'FW-H equation'

Author: Grafiati

Published: 1 April 2023

Last updated: 31 July 2025

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1

Kusyumov, Alexander, Sergey Mikhailov, Sergey Kusyumov, Elena Romanova, and Georgios Barakos. "Some Peculiarities of Helicopter Main Rotor Aeroacoustic for Far-Field Observer." EPJ Web of Conferences 213 (2019): 02048. http://dx.doi.org/10.1051/epjconf/201921302048.

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Mathematical models for helicopter rotor acoustics are usually based on the Ffowcs Williams–Hawkings (FW–H) equation. The level of rotor noise is determined by geometry (thickness noise) of a flying vehicle and distributed blade loading (loading noise). Initially, the FW-H equation was obtained from Euler’s equations and does not depend on the viscosity of flow. In the present work the UH-1H helicopter is considered as a test case for numerical CFD simulation and comparison to experimental data.

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2

Tao, Jun, Gang Sun, Ying Hu, and Miao Zhang. "Noise Prediction for Multi-Element Airfoil Based on FW-H Equation." Applied Mechanics and Materials 52-54 (March 2011): 1388–93. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.1388.

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In this article, four observation points are selected in the flow field when predicting aerodynamic noise of a multi-element airfoil for both a coarser grid and a finer grid. Numerical simulation of N-S equations is employed to obtain near-field acoustic information, then far-field acoustic information is obtained through acoustic analogy theory combined with FW-H equation. Computation indicates: the codes calculate the flow field in good agreement with the experimental data; The finer the grid is, the more stable the calculated sound pressure level (SPL) is and the more regularly d(SPL)/d(St)

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3

Najafi-Yazdi, Alireza, Guillaume A. Brès, and Luc Mongeau. "An acoustic analogy formulation for moving sources in uniformly moving media." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 467, no. 2125 (2010): 144–65. http://dx.doi.org/10.1098/rspa.2010.0172.

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Acoustic analogy methods are used as post-processing tools to predict aerodynamically generated sound from numerical solutions of unsteady flow. The Ffowcs Williams–Hawkings (FW–H) equation and related formulations, such as Farassat’s Formulations 1 and 1A, are among the commonly used analogies because of their relative low computation cost and their robustness. These formulations assume the propagation of sound waves in a medium at rest. The present paper describes a surface integral formulation based on the convective wave equation, which takes into account the presence of a mean flow. The f

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4

Lyrintzis, Anastasios S. "Surface Integral Methods in Computational Aeroacoustics—From the (CFD) Near-Field to the (Acoustic) Far-Field." International Journal of Aeroacoustics 2, no. 2 (2003): 95–128. http://dx.doi.org/10.1260/147547203322775498.

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A review of recent advances in the use of surface integral methods in Computational AeroAcoustics (CAA) for the extension of near-field CFD results to the acoustic far-field is given. These integral formulations (i.e. Kirchhoff's method, permeable (porous) surface Ffowcs-Williams Hawkings (FW-H) equation) allow the radiating sound to be evaluated based on quantities on an arbitrary control surface if the wave equation is assumed outside. Thus only surface integrals are needed for the calculation of the far-field sound, instead of the volume integrals required by the traditional acoustic analog

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5

Seol, Hanshin, Cheolsoo Park, and Ki-Sup Kim. "Numerical Prediction of Marine Propeller BPF Noise Using FW-H Equation and Its Experimental Validation." Transactions of the Korean Society for Noise and Vibration Engineering 26, no. 6_spc (2016): 705–13. http://dx.doi.org/10.5050/ksnve.2016.26.6.705.

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6

Chen, Li, Yang Yu, and Guo Xiang Hou. "Flow-Induced Noise Radiation from the Rotational Bodies Based on Fluid Mechanics Using Hybrid Immersed Boundary Lattice-Boltzmann/FW-H Method." Applied Mechanics and Materials 345 (August 2013): 345–48. http://dx.doi.org/10.4028/www.scientific.net/amm.345.345.

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A novel study of the simulations of the flow-induced noise from the moving boundary objects using the hybrid immersed boundary lattice-Boltzmann method (IB-LBM), which is the modern useful numerical method of fluid mechanics, on the Ffowcs Williams-Hawkings (FW-H) equation is carried out. The permeable surface FW-H method has been demonstrated an effective technique of the far-field noise predication, because of its complete theories and successful applications in aeroacoustics. It usually need the information of the field near sound source. Therefore, we also adopt the effective and widely us

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7

Guo, H., YS Wang, F. Zhu, NN Liu, and C. Yang. "Multi-field coupling prediction for improving aeroacoustic performance of muffler based on LES and FW-H acoustic analogy methods." International Journal of Aeroacoustics 20, no. 3-4 (2021): 414–36. http://dx.doi.org/10.1177/1475472x211005409.

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Based on the large eddy simulation (LES) and Ffowcs Williams and Hawkings (FW-H) equation, a multi-field coupling method is presented for aeroacoustic prediction of a muffler with high-speed and high-temperature exhaust gasflow. A three-dimensional finite-volume model of the muffler is established by using the LES and FW-H acoustic analogy (FW-H-AA) methods. Experimental validations of the simulated results suggest a good accuracy of the combined LES and FW-H-AA approach. Some factors influencing on noise attenuation, such as the gasflow velocity, temperature and the structural parameters of t

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8

Li, Zhibin, Wei Sun, Yuni Zhang, Zihan Zhang, and Lusheng Jiang. "Aeroacoustic Analysis of Rotor in Forward Flight Considering Blade Elastic Deformation." Journal of Physics: Conference Series 2890, no. 1 (2024): 012060. http://dx.doi.org/10.1088/1742-6596/2890/1/012060.

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Abstract A rotor aeroacoustic calculation model of the rotor in forward flight based on CAMRAD II and FW-H equation was established, which can involve blade elastic deformation. CAMRAD II was used to calculate the actual motion of the blade and the rotor’s unsteady aerodynamic load based on the elastic blade model. The blade dynamics module in the noise calculation program was replaced to consider the blade elastic deformation in forward flight based on the FW-H equation. The forward flight noise characteristics of a full scale rotor were researched. The research shows that the rotor has obvio

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9

Khelladi, Sofiane, and Farid Bakir. "A Consistency Test of Thickness and Loading Noise Codes Using Ffowcs Williams and Hawkings Equation." Advances in Acoustics and Vibration 2010 (July 4, 2010): 1–6. http://dx.doi.org/10.1155/2010/174361.

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The thickness noise predicted by the Ffowcs Williams and Hawkings (FW&H) equation depends on the normal velocity which is very sensitive to the meshing size. Isom showed that in far field a monopolar source is equivalent to a dipolar source induced by a uniform distribution of the load on the entire moving surface. The main objective of this paper is to determine a specific expression of Isom's thickness noise in time and frequency domains for subsonic fans. The scope of the proposed expression of Isom's thickness noise is to define a benchmark test of consistency for thickness and loading

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10

Bozorgi, Alireza, Leonidas Siozos-Rousoulis, Seyyed Ahmad Nourbakhsh, and Ghader Ghorbaniasl. "A two-dimensional solution of the FW-H equation for rectilinear motion of sources." Journal of Sound and Vibration 388 (February 2017): 216–29. http://dx.doi.org/10.1016/j.jsv.2016.10.035.

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11

Huang, Zhongjie, Leonidas Siozos-Rousoulis, Tim De Troyer, and Ghader Ghorbaniasl. "Helicopter rotor noise prediction using a convected FW-H equation in the frequency domain." Applied Acoustics 140 (November 2018): 122–31. http://dx.doi.org/10.1016/j.apacoust.2018.04.040.

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12

Ryu, Seo Yoon, Cheolung Cheong, Jong Wook Kim, and Byung il Park. "Development of virtual fan flow and acoustic performance testers based on RANS solvers and acoustic analogy." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 2 (2021): 4336–42. http://dx.doi.org/10.3397/in-2021-2667.

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As the potential of computational resources dramatically increases, the so-called computer-aided engineering readily replaces experiment-based engineering in related industrial fields. In this study, the virtual fan flow and acoustic performance testers are developed using the RANS solvers and the acoustic analogy. Two types of forward-curved centrifugal fans are selected for numerical and experimental investigations into its flow and acoustic performances. First, to experimentally evaluate the performances of the centrifugal fan units, their P-Q curves and sound power levels are measured usin

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13

Wang, Zeyang, Jun Huang, and Mingxu Yi. "Acoustic scattering effect prediction of helicopter fuselage based on BEM and convective FW–H equation." Acta Acustica 6 (2022): 24. http://dx.doi.org/10.1051/aacus/2022019.

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The main acoustic noise source of helicopters is supposed to be the rotor blades, but the scattering effect of the helicopter fuselage sometimes cannot be ignored. For the accuracy of acoustic noise prediction and the research on the scattering affections of the helicopter fuselage, an FWH–BEM Method (FBM) based on convective FW–H equation and boundary element method (BEM) is presented for the prediction of the noise scattering effects of helicopter fuselage and the approach to the calculation of a helicopter’s acoustic noise field. In this paper, different fuselage models are adopted for the

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14

Huang, Surui, Kai Yang, Chengyuan Sun, and Leilei Shi. "Research on finite element model of rotor aerodynamicnoise in hovering state." Journal of Physics: Conference Series 2756, no. 1 (2024): 012009. http://dx.doi.org/10.1088/1742-6596/2756/1/012009.

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Abstract The helicopter has been widely used in many fields, and the rotor aerodynamic noise has gradually attracted attention. The non-homogeneous wave equation, Ffowcs Williams-Hawkings equation (FW-H equation) derived from hydrodynamic N-S equation, combined with RANS turbulence simulation, was used to simulate the sound field of NACA0012 airfoil-shape model in hovering state. On this basis, by changing the thickness and camber of the blade, the aerodynamic noise of the rotor under different airfoil profile thickness and camber is calculated. The results show that the change of airfoil thic

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15

Guo, Chunyu, Xu Wang, Chongge Chen, Yinghong Li, and Jian Hu. "Numerical Investigation of Self-Propulsion Performance and Noise Level of DARPA Suboff Model." Journal of Marine Science and Engineering 11, no. 6 (2023): 1206. http://dx.doi.org/10.3390/jmse11061206.

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Propulsion noise is an enduring problem of significant military and environmental importance. Hence, it is crucial to investigate propeller noise characteristics. In this study, the hydrodynamic performance and noise level of the DARPA (Defense Advanced Research Projects Agency) Suboff submarine with the E1619 propeller were analyzed. The hull resistance and propeller hydrodynamics were studied separately, and the numerical results were validated using available experimental values. The self-propulsion point was determined by matching the hull resistance and propeller thrust following ITTC (In

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16

Zhou, Zhiteng, Yi Liu, Hongping Wang, and Shizhao Wang. "Mass-Conserved Solution to the Ffowcs-Williams and Hawkings Equation for Compact Source Regions." Aerospace 10, no. 2 (2023): 148. http://dx.doi.org/10.3390/aerospace10020148.

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A mass-conserved formulation for the Ffowcs-Williams–Hawkings (FW–H) integral is proposed to suppress contributions of spurious mass flux to the far-field sound at very low Mach numbers. The far-field condition and compact-source region assumptions are employed. By using higher-order derivatives of Green’s function, an expansion of the integrand in the monopole term is performed. This expansion transforms the mass-flux like monopole term into a series including different orders of velocity moment. At very low Mach numbers, the zero-order term is exactly the contribution from the spurious mass

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17

Qiaorui, Si, Jinfeng Liu, Asad Ali, et al. "Study on flow-induced noise propagation mechanism of cylinder–airfoil interference model by using large eddy simulation combined with vortex–acoustic equation." AIP Advances 13, no. 3 (2023): 035305. http://dx.doi.org/10.1063/5.0138084.

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An innovative numerical prediction method of flow-induced noise is implemented to overcome the defect that the traditional acoustic analogy method cannot reflect the interaction between turbulence vortex and sound. The classical cylindrical–airfoil interference model is used to perform the simulation and compared with the experimental results. To start with the derivation of Powell’s vortex sound equation, an implicit three-dimensional model of the fluid–acoustic coupling field is established to process the unsteady iterative calculation. The large eddy simulation method is adopted to solve th

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18

Choi, Jinho, Wonick Choi, Jinman Jang, Bosun Chung, and Youngsoo Kim. "Investigation on the comparison analysis of the characteristics between the Forward and Backward curved fan system and the Improvement on flow/noise performances by optimizing blade angles in clothes dryers." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 268, no. 5 (2023): 3486–96. http://dx.doi.org/10.3397/in_2023_0499.

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Recently, the needs for clothes dryers are rapidly increasing due to the consumer's interest in convenience for time reducing and cleanliness like dust. The drying performance of these clothes dryers is greatly affected by the fan system. The fan system affects the flow performance and is related to drying time of clothes dryer. Also, the aerodynamic noise generated by the fan system in the dryer has a great influence on the overall noise of the machine. Because of these reasons, many manufacturers are conducting researches on improving the performance of the fan system in the dryers. The purp

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19

Malainine, Maymouna, Amany Khaled, and Sameh M. Shabaan. "Aeroacoustics behavioral study of Savonius wind turbine." Journal of Physics: Conference Series 2128, no. 1 (2021): 012033. http://dx.doi.org/10.1088/1742-6596/2128/1/012033.

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Abstract Vertical Axis Wind Turbines (VAWTs) are appropriate for use in populated areas. If VAWTs were installed at residential areas, the generated aerodynamic noise can be harmful in a way or another. Therefore, in the present study, the aero-acoustics of the conventional Savonius Wind turbine was investigated using Computational Fluid Dynamics (CFD). Both the Unsteady Reynolds-averaged Navier-Stokes (URANS) equations and impermeable Ffowcs Wiliams and Hawkings (FW-H) equation were simultaneously solved. The effect of speed ratio was also studied. The results indicate that; the pressure is i

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20

Qin, Qikai, Dejiang Shang, Yongwei Liu, and Tianyu Wang. "Prediction of flow noise around a cylinder based on Large-Eddy Simulation and acoustic analogy method." MATEC Web of Conferences 283 (2019): 08003. http://dx.doi.org/10.1051/matecconf/201928308003.

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In this article, a hybrid method combining large eddy simulation with acoustic analogy is presented to predict three-dimensional far field noise induced by flow around a cylinder. Firstly, the governing equation including RANS equations with shear-stress transport (SST) k-ω turbulent model is numerically solved for steady flow field by using Ansys Fluent. Transient flow field is numerically solved by LES. Then, the flow field simulation results are used to compute the flow-induced noise with the FW-H integral equation method and BEM method based on Lighthill acoustic analogy equation in Actran

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21

Jia, S. H., B. Yang, X. L. Zhao, and J. Z. Xu. "Numerical simulation of far field acoustics of an airfoil using vortex method and 2-D FW-H equation." IOP Conference Series: Materials Science and Engineering 52, no. 2 (2013): 022047. http://dx.doi.org/10.1088/1757-899x/52/2/022047.

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22

Diémé, Mohamad M., Maxime Hervy, Saïdou N. Diop, et al. "Sustainable Conversion of Agriculture and Food Waste into Activated Carbons Devoted to Fluoride Removal from Drinking Water in Senegal." International Journal of Chemistry 8, no. 1 (2015): 8. http://dx.doi.org/10.5539/ijc.v8n1p8.

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<p>The objective of this study was to investigate the production of activated carbons (AC) from cashew shells, and millet stalks and their efficiency in fluoride retention. These agricultural residues are collected from Senegal. It is known that some regions of Sénégal, commonly called the groundnut basin, are affected by a public health problem caused by an excess of fluoride in drinking water used by these populations. The activated carbons were produced by a combined pyrolysis and activation with water steam; no other chemical compounds were added. Then, activated carbonaceous materia

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23

Huang, Surui, Chengyuan Sun, Yaodong Yang, Hongchang Chen, and Kai Yang. "Numerical simulation of the effect of helicopter flight advance ratio and lift rate on rotor aerodynamic noise." Journal of Physics: Conference Series 2764, no. 1 (2024): 012048. http://dx.doi.org/10.1088/1742-6596/2764/1/012048.

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Abstract To study the aerodynamic noise characteristics of helicopter rotors under different flight states, this paper combined with the FW-H calculation equation, adopted NACA0012 airfoil and ROBIN fuselage to form a helicopter model and used FLUENT software to simulate different flight states of the helicopter. The influence of the two flight parameters, advance ratios, and lift rates, on the aerodynamic noise characteristics of the rotor, is studied. The results show that with the increase of helicopter advance ratio, the aerodynamic noise generated by the rotor becomes larger, and the effe

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Wang, Yanqing, Wei Kang, and Shilin Hu. "Aeroacoustic Analysis of Rapid Position Changing Process of Missile Seeker Equipment." Journal of Physics: Conference Series 2658, no. 1 (2023): 012034. http://dx.doi.org/10.1088/1742-6596/2658/1/012034.

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Abstract A two-dimensional CFD model of the rapid position-changing of missile seeker equipment is presented to study its aeroacoustic impact. By combining the computational fluid dynamics (CFD) with the Ffowcs Williams-Hawkings (FW-H) equation, the flow and related aeroacoustic features are analyzed under different flight Mach numbers and flight heights. The impact of seeker movement on the flow field and aerodynamic noise are highlighted. The results indicate that the spectrum peak of sound pressure level increases with the vortex shedding frequency as the flight Mach number increases. As th

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Hu, H. R., C. Zhang, and X. Wang. "Numerical acoustic simulation of flow around circular cylinders based on Lattice Boltzmann method and Ffowcs Williams-Hawkings acoustic equation." International Journal of Computational Materials Science and Engineering 07, no. 01n02 (2018): 1850010. http://dx.doi.org/10.1142/s2047684118500100.

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Based on the GPU acceleration technique, Lattice Boltzmann method (LBM) and Ffowcs Williams-Hawkings (FW-H) acoustic equation are adopted to simulate the noise generated by flow around fixed and rotating circular cylinders when Reynolds number (Re) is 200. The results show that the sound pressure level has a peak in the vertical direction and it is higher than that in the streamwise direction. The maximum sound pressure level is significantly reduced when the cylinder rotates due to the suppression of vortex shedding compared to the case of a fixed cylinder. For tandem cylinders, the maximum s

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Long, Shuang Li, Hong Nie, and Xin Xu. "Aeroacoustic Study on a Simplified Nose Landing Gear." Applied Mechanics and Materials 184-185 (June 2012): 18–23. http://dx.doi.org/10.4028/www.scientific.net/amm.184-185.18.

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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 no

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Nitzsche, F., and D. G. Opoku. "Acoustic validation of a new code using particle wake aerodynamics and geometrically-exact beam structural dynamics." Aeronautical Journal 109, no. 1096 (2005): 257–67. http://dx.doi.org/10.1017/s0001924000000713.

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Abstract This paper describes the validation of a new code for prediction both aeroacoustic and aeroelastic behaviour of hingeless rotors. The structural component is based on a non-linear beam element model considering small strains and finite rotations, which uses a mixed variational intrinsic formulation. The aerodynamic component is built on a loworder panel method incorporating a vortex particle free-wake model. The aerodynamic and structural components are combined to form a closely coupled aeroelastic code that solves in the time-domain. The loading and thickness noise terms for the aer

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Le, Quang Quyen. "BUILDING AND VERIFYING A TOOL FOR CALCULATING THE AERODYNAMIC NOISE OF HELICOPTER ROTORS." Journal of Science and Technique 17, no. 5 (2022): 58–69. http://dx.doi.org/10.56651/lqdtu.jst.v17.n05.530.

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This article presents an approach to build and verify a tool for calculating aerodynamic noise characteristics of helicopter rotors. The calculation tool is built on the basis of combining the vortex lattice method and the Formulation 1A of Farrasat, which is one of solutions of the Ffowcs Williams-Hawkings (FW-H) equation. By comparing the obtained result with data from reputable international publications, the calculation tool is verified for accuracy and reliability. The variation and value of the acoustic pressure from this calculation tool are in a good agreement with the international pu

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Souliez, F. J., L. N. Long, P. J. Morris, and A. Sharma. "Landing Gear Aerodynamic Noise Prediction Using Unstructured Grids." International Journal of Aeroacoustics 1, no. 2 (2002): 115–35. http://dx.doi.org/10.1260/147547202760236932.

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Aerodynamic noise from a landing gear in a uniform flow is computed using the Ffowcs Williams-Hawkings (FW-H) equation. The time accurate flow data on the integration surface is obtained using a finite volume low-order flow solver on an unstructured grid. The Ffowcs Williams-Hawkings equation is solved using surface integrals over the landing gear surface and over a permeable surface away from the landing gear. Two geometric configurations are tested in order to assess the impact of two lateral struts on the sound level and directivity in the far-field. Predictions from the Ffowcs Williams-Haw

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Hajczak, Antoine, Laurent Sanders, François Vuillot, and Philippe Druault. "A comparison between off and on-body control surfaces for the FW-H equation: Application to a non-compact landing gear wheel." Journal of Sound and Vibration 490 (January 2021): 115730. http://dx.doi.org/10.1016/j.jsv.2020.115730.

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Yu, Lianjie, Weiwen Zhao, and Decheng Wan. "Dual Mesh Technique for Hydroacoustic Prediction of Cavitating Flows around a Three-Dimensional Bullet." Journal of Physics: Conference Series 2458, no. 1 (2023): 012021. http://dx.doi.org/10.1088/1742-6596/2458/1/012021.

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Abstract Nowadays, hydroacoustics is of great importance. A major source of underwater noise is cavitation noise. One of the difficulties in cavitation noise prediction is its complex formation mechanism. In this paper, a cavitating bullet is taken as the research object, and detailed numerical simulation research of the local cavitation for this three-dimensional model is carried out. Ffowcs Williams and Hawkings equation (FW-H) is adopted. The quadrupole term is obtained by the direct volume integration method. Furthermore, dual mesh technique is adopted to achieve fast calculation. The resu

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Chew, Ying Ming, and V. An-Erl King. "Microwave Drying of Pitaya (Hylocereus) Peel and the Effects Compared with Hot-Air and Freeze-drying." Transactions of the ASABE 62, no. 4 (2019): 919–28. http://dx.doi.org/10.13031/trans.13193.

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Abstract. Microwave drying (MD) of pitaya peel was performed at 75, 225, 375, 525, and 750 W. The drying effects on the effective moisture diffusivity (De), total polyphenol content (TPC), betalain content, DPPH scavenging ability, and rehydration abilities of pitaya peel were examined. The data were compared with hot-air drying (HD) at 100°C for 4 h and freeze-drying (FD) for 24 h. The results showed that the MD kinetics of pitaya peel fit Fick’s law and the Arrhenius equation with an activation energy (Ea) of 34.08 W g-1. The De values of MD, which ranged from 2.35E-07 m2 s-1 (at 75 W) to 5.

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Shi, Fangcheng, Fushan Shi, Xudong Tian, and Tiantian Wang. "Numerical Study on Aerodynamic Noise Reduction of Pantograph." Applied Sciences 12, no. 21 (2022): 10720. http://dx.doi.org/10.3390/app122110720.

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A hybrid method incorporating the simulations of noise sources with delayed detached eddy simulation (DDES) and calculations of far-field noise with the Ffowcs Williams–Hawkings (FW-H) equation is used to study the suppression technique for the aerodynamic noise of a Faiveley CX-PG pantograph. Considering that China’s Fuxing bullet trains operate at 350 km/h, the inflow velocity of 350 km/h is applied in this paper. The noise radiated from the panhead area, middle area, and bottom area at an inflow velocity of 350 km/h is distinguished. The noise intensities at the standard observer show that

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Ju, Shengjun, Zhenxu Sun, Dilong Guo, Guowei Yang, Yeteng Wang, and Chang Yan. "Aerodynamic-Aeroacoustic Optimization of a Baseline Wing and Flap Configuration." Applied Sciences 12, no. 3 (2022): 1063. http://dx.doi.org/10.3390/app12031063.

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Optimization design was widely used in the high-lift device design process, and the aeroacoustic reduction characteristic is an important objective of the optimization. The aerodynamic and aeroacoustic study on the baseline wing and flap configuration was performed numerically. In the current study, the three-dimensional Large Eddy Simulation (LES) equations coupled with dynamic Smagorinsky subgrid model and Ffowcs–William and Hawkings (FW–H) equation are employed to simulate the flow fields and carry out acoustic analogy. The numerical results show reasonable agreement with the experimental d

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Li, Long Shuang, Hong Nie, and Xin Xu. "Simulation and Experiment on Landing Gear Component Noise." Applied Mechanics and Materials 170-173 (May 2012): 3454–59. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.3454.

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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 no

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36

GAYET, Christophe, and Rodrigo AUZA GUTIERREZ. "Aerodynamic and aeroacoustic characterization of an axial fan using Adaptive Mesh Refinement (AMR) based CFD and CAA." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 270, no. 10 (2024): 1363–74. http://dx.doi.org/10.3397/in_2024_2951.

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This work focuses on numerical analysis of a low-pressure axial fan using Computational Fluid Dynamics (CFD) and Computational Aeroacoustics (CAA) methods. These simulations are performed with the commercial software Hexagon's Cradle scFLOW. The investigation focuses on flow prediction using incompressible Large Eddy Simulation (LES), and acoustic propagation based on the Ffowcs Williams-Hawkings (FW-H) equation. We present a method to evaluate the mesh resolution for LES and a mesh refinement approach to resolve strong flow interactions, particularly near the tip-gap region. Both the aerodyna

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Gu, Mengfan, and Baowei Song. "Aeroacoustic Noise Characteristics of Flow around a Square Column Based on Large Eddy Simulation." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 38, no. 3 (2020): 465–70. http://dx.doi.org/10.1051/jnwpu/20203830465.

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Large eddy simulation and Ffowcs Williams-Hawkings (FW-H) equation were used to investigate the aeroacoustic noise characteristics of flow around a square column. After verifying the accuracy of the numerical model, the influences of flow velocity and flow direction on noise field characteristics are discussed. The noise prediction result of the base model was in good agreement with the experiment data in the vortex-shedding frequency and in the general trend. It was shown that there were typical dipole noise sources in the direction of 110° and 250°, respectively. With the increase of distanc

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Yu, An, Xincheng Wang, Zhipeng Zou, Qinghong Tang, Huixiang Chen, and Daqing Zhou. "Investigation of Cavitation Noise in Cavitating Flows around an NACA0015 Hydrofoil." Applied Sciences 9, no. 18 (2019): 3736. http://dx.doi.org/10.3390/app9183736.

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To provide theoretical basis for cavitation noise control, the cavitation evolution around a hydrofoil and its induced noise were numerically investigated. A modified turbulence model and Zwart cavitation model were employed to calculate the flow field and predict the cavitation phenomenon accurately. Then, the acoustic analogy method based on the Ffowcs Williams-Hawking (FW-H) equation was applied to analyze the cavitation-induced noise. Seven cavitation numbers were selected for analysis. Acoustic power spectral density (PSD) and acoustic pressure were investigated to establish the relations

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Xu, Min. "Prediction of cylinder aerodynamic noise using hybrid non-reflecting characteristic boundaries and acoustic analogy method." Journal of Physics: Conference Series 3030, no. 1 (2025): 012023. https://doi.org/10.1088/1742-6596/3030/1/012023.

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Abstract To analyze the influence of reflected sound waves from boundaries on the prediction of cylinder aerodynamic noise using the acoustic analogy method, a hybrid non-reflecting boundary condition (HNRBC) was applied to the large eddy simulations of aerodynamic noise sources and propagated acoustic near fields. The FW-H equation was utilized to predict the far-field noise. The calculated results were compared with various non-reflecting boundary conditions (NRBC). The study shows that the sources and far-fields are slightly affected by reflected waves, whereas the noise near-fields are qui

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Nose, H., G. W. Mack, X. R. Shi, and E. R. Nadel. "Shift in body fluid compartments after dehydration in humans." Journal of Applied Physiology 65, no. 1 (1988): 318–24. http://dx.doi.org/10.1152/jappl.1988.65.1.318.

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To investigate the influence of [Na+] in sweat on the distribution of body water during dehydration, we studied 10 volunteer subjects who exercised (40% of maximal aerobic power) in the heat [36 degrees C, less than 30% relative humidity (rh)] for 90-110 min to produce a dehydration of 2.3% body wt (delta TW). After dehydration, the subjects rested for 1 h in a thermoneutral environment (28 degrees C, less than 30% rh), after which time the changes in the body fluid compartments were assessed. We measured plasma volume, plasma osmolality, and [Na+], [K+], and [Cl-] in plasma, together with swe

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Malefaki, Iro, and Kostas Belibassakis. "A Novel FDTD–PML Scheme for Noise Propagation Generated by Biomimetic Flapping Thrusters in the Ocean Environment." Journal of Marine Science and Engineering 10, no. 9 (2022): 1240. http://dx.doi.org/10.3390/jmse10091240.

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Biomimetic flapping-foil thrusters can operate efficiently while offering desirable levels of thrust required for the propulsion of a small vessel or an Autonomous Underwater Vehicle (AUV). These systems have been studied both as main propulsion devices and for augmenting ship propulsion in waves. In this work, the unsteady hydrofoil loads are used to calculate the source terms of the Ffowcs Williams–Hawkings (FW-H) equation which is applied to model noise propagation in the underwater ocean acoustic environment. The solution provided by a simplified version of the Farassat formulation in free

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Guo, Jing, Xiao-Ming Tan, Zhi-Gang Yang, Yu-Qi Xue, Ya-Nan Shen, and Hao-Wei Wang. "Aeroacoustic Optimization Design of the Middle and Upper Part of Pantograph." Applied Sciences 12, no. 17 (2022): 8704. http://dx.doi.org/10.3390/app12178704.

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The pantograph is the main noise source of high-speed trains, of which the middle and upper parts of the pantograph account for about 50% of the whole noise energy. Taking CRH380BL pantograph as the basic prototype, three aerodynamic noise reduction measures of opening, slotting, and airfoil are introduced to build a new pantograph, and their aeroacoustic performances are comprehensively investigated through large eddy simulation (LES) and Ffowcs Williams–Hawkings (FW-H) equation method. The research results show that the open upper and lower arms (ULA) can reduce the downstream vorticity inte

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Hua, Jie, and Reda R. Mankbadi. "Prediction and Control of Broadband Noise Associated with Advanced Air Mobility—A Review." Applied Sciences 14, no. 18 (2024): 8455. http://dx.doi.org/10.3390/app14188455.

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This review presents an overview of advanced air mobility broadband noise (BBN) prediction and control techniques, highlighting significant advancements in various prediction models. Methods such as the semi-empirical Brooks–Pope–Marcolini (BPM) model, analytical Amiet model, and time-domain models based on the FW-H equation have been extensively studied. Machine learning (ML) shows promise in BBN prediction but requires extensive data training and application to noise source mechanisms. Passive control methods, such as leading and trailing edge serrations and blade tip designs, have been part

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Rismondo, Giacomo, Marta Cianferra, and Vincenzo Armenio. "Acoustic Response of a Vibrating Elongated Cylinder in a Hydrodynamic Turbulent Flow." Journal of Marine Science and Engineering 10, no. 12 (2022): 1918. http://dx.doi.org/10.3390/jmse10121918.

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The present paper contains the results of the numerical analysis of the interaction between a Newtonian incompressible turbulent flow and a linear elastic slender body, together with the influence of the fluid–structure interaction (FSI) on the noise generation and propagation. The purpose is to evaluate the differences in term of acoustic pressure between the case where the solid body is rigid (infinite stiffness) and the case where it is elastic (finite stiffness). A partitioned and implicit algorithm with the arbitrary Lagrangian–Eulerian method (ALE) is used for the interaction between the

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Purwana, Agung, I. Made Ariana, and Wisnu Wardhana. "Numerical study on the cavitation noise of marine skew propellers." Journal of Naval Architecture and Marine Engineering 18, no. 2 (2021): 97–107. http://dx.doi.org/10.3329/jname.v18i2.38099.

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In this study, numerical simulations on the noise of the underwater marine propeller for different pressures, skew angles, and performance conditions are investigated. The study has been carried out for the prediction of cavity and noise cavitation characteristics of the propeller. The blade sheet cavitation created by an underwater propeller is then evaluated using numerical analysis. The cavitation and cavity around marine propellers were predicted using MRF (Multiple Reference Frame) techniques. The simulation uses the Reynolds Averaged Navier-Stokes (RANS) formulation with the turbulence m

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YUAN, Mingchuan, Huixun SUN, Zhibin LI, Qingfeng NIU, and Feng FAN. "Numerical calculation and analysis of aero-acoustic characteristics of tilt rotor in different tilt angles." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 42, no. 2 (2024): 205–13. http://dx.doi.org/10.1051/jnwpu/20244220205.

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The numerical calculation model for the aero-acoustic analysis of a tilt rotor was established by combining the free wake method and the FW-H (Ffowcs Williams-Hawkings) equation. The numerical method was validated by using the tilt rotor′s aero-acoustic test results. The aero-acoustic characteristics of dual tilt rotors that take into account the force and moment trim of an aircraft in its typical transition path were calculated. The unsteady air load of a rotor blade and its noise data in different observational positions were acquired. The acoustic directivity and sound pressure level of the

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Song, Xiang, Peixun Yu, Junqiang Bai, Xiao Han, and Jiahui Peng. "Aerodynamic and Aeroacoustic Optimization of Propeller Based on Hanson Noise Model." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 38, no. 4 (2020): 685–94. http://dx.doi.org/10.1051/jnwpu/20203840685.

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Aiming at the multi-objective optimization design problem of propeller aerodynamics and noise, the three-dimensional geometric deformation of the whole blade is carried out by the free-form surface deformation method based on non-uniform rational B-spline. In order to save the calculation cost of optimization, the RANS method and the Hanson model are combined to predict pure tone noise, and the prediction accuracy is comparable to the accuracy of the FW-H equation coupled with URANS method. Kriging surrogate model and non-dominated sorting genetic algorithm are used to search for optimal value

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Belibassakis, Kostas, John Prospathopoulos, and Iro Malefaki. "Scattering and Directionality Effects of Noise Generation from Flapping Thrusters Used for Propulsion of Small Ocean Vehicles." Journal of Marine Science and Engineering 10, no. 8 (2022): 1129. http://dx.doi.org/10.3390/jmse10081129.

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Flapping-foil thrusters are systems that operate at a substantially lower frequency compared with marine propellers and are characterized by a much smaller power concentration. These biomimetic devices are able to operate very efficiently, offering desirable levels of thrust required for the propulsion of small vessels or autonomous underwater vehicles (AUVs), and can be used for the standalone propulsion of small vessels or for augmenting ship propulsion in waves, alleviating the generation of noise and its adverse effects on sea life, particularly on marine mammals. In this work, we consider

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Li, Fang, Qiaogao Huang, Guang Pan, and Yao Shi. "Effect of wavy leading edge on hydrofoil-turbulence interaction noise." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 39, no. 6 (2021): 1266–73. http://dx.doi.org/10.1051/jnwpu/20213961266.

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In order to solve the underwater noise pollution and improve the acoustic stealth performance of underwater vehicles, NACA0020 was bionically modified according to the structure of the leading edge tubercles of humpback fin. The flow field and noise characteristics of the hydrofoil-turbulent interaction model before and after the modification were studied by using the large eddy simulation and the FW-H equation. The results show that the wavy leading edge can effectively reduce the turbulence interaction noise of the hydrofoil, especially the broadband noise after 89.55 Hz. The overall sound p

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Dang, Zhigao, Zhaoyong Mao, and Wenlong Tian. "Reduction of Hydrodynamic Noise of 3D Hydrofoil with Spanwise Microgrooved Surfaces Inspired by Sharkskin." Journal of Marine Science and Engineering 7, no. 5 (2019): 136. http://dx.doi.org/10.3390/jmse7050136.

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Loud hydrodynamic noise is not only potentially harmful to the health of organisms in the ocean, but it is also a threat to the survival of underwater vehicles. Different from the general noise reduction technologies at present, a new idea for a flow-induced noise reduction design with spanwise microgrooved surfaces inspired by sharkskin is introduced in this paper. Large eddy simulations (LES) combined with the Ffowcs Williams and Hawkings (FW-H) equation are adopted to simulate the hydrodynamic noise of the three-dimensional (3D) hydrofoil. The accuracy of the numerical predictions is checke

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