Numerical simulation for prediction of aerodynamic noise characteristics on a HAWT of NREL phase VI

2011 ◽  
Vol 25 (5) ◽  
pp. 1341-1349 ◽  
Author(s):  
Jang-Oh Mo ◽  
Young-Ho Lee
Keyword(s):  
Numerical Simulation ◽  
Aerodynamic Noise ◽  
Noise Characteristics ◽  
Nrel Phase Vi

scholarly journals Numerical simulation and experimental research on the aerodynamic performance of large marine axial flow fan with a perforated blade

2017 ◽  
Vol 37 (3) ◽  
pp. 410-421 ◽  
Author(s):  
Xinglin Yang ◽  
Chenhui Wu ◽  
Huabing Wen ◽  
Linglong Zhang
Keyword(s):  
Numerical Simulation ◽  
Noise Reduction ◽  
Axial Flow ◽  
Internal Flow ◽  
Experimental Tests ◽  
Aerodynamic Noise ◽  
Surface Boundary ◽  
Axial Flow Fan ◽  
Suction Surface ◽  
Noise Characteristics

In this study, some of the optimal parameters for a new-style marine axial flow fan are defined by using numerical simulation and experimental tests with a large marine axial flow fan, based on the analysis of the blade perforation’s influences on its internal flow field and aerodynamic noise characteristics. Test result shows that the noise reduction for the axial flow fan with perforated blade is about 3 dB when the blade perforation diameter D is 10 mm and its deflection angle α is 45°. The results of the study show that there is an inhibitory effect on the discrete noise of axial flow fan with perforated blade on the tip area, and its total noise level emerged as the fluctuated distribution characteristics with the increase in the perforation diameter D and reduced along with the increase in the deflection of perforation angle α, at the same time varied as a linear characteristics, which can be reasonably explained by the acoustic interference theory. The results of the study have also further confirmed that the improvement of the flow of axial flow fan with perforated blade helps to reduce the pressure pulsation amplitude caused by the turbulence of the blade surface boundary layer, thereby suppressing the back-flow and vortex from the pressure surface to the suction surface efficiently. It is indicated that the improved vortex shedding phenomenon at the blade trailing edge after perforation on the area of blade tip is the main reason for the aerodynamic noise reduction of axial flow fan.

Study on the Influence of Inlet Asymmetry on Aerodynamic Noise of Cooling Fan

2020 ◽  
Author(s):  
Jie Tian ◽  
Zonghan Sun ◽  
Pengfei Chai ◽  
Hua Ouyang
Keyword(s):  
Heat Dissipation ◽  
Electronic Device ◽  
Numerical Study ◽  
Rotor Blades ◽  
Aerodynamic Noise ◽  
Sampling Point ◽  
Inlet Flow ◽  
Cooling Fan ◽  
Noise Characteristics ◽  
Correction Technique

Abstract Experimental and numerical studies on the aerodynamic noise characteristics of a variable-speed axial fan commonly used for electronic device heat dissipation were conducted. First, the far-field noise spectrum of the fan was measured using a microphone array on the contour plane of the fan axis. The spectral analysis indicated that the discrete single-tone noise energy ratio was high, which indicates that it was the dominant aerodynamic noise. Afterwards, the double-uniform sampling point mode correction technique, which is based on the circumferential acoustic mode measurement method, was used to obtain the modal distribution on the inlet and outlet sides of the cooling fan. The influence of inlet unevenness on the cooling fan was identified. The traditional Tyler-Sofrin rotor-stator interaction formula was modified to account for the non-axisymmetric shape of the fan inlet bellmouth. The validity of the modified formula was verified by measuring the circumferential acoustic modes of three cooling fans with different rotor and strut counts. Furthermore, a CFD numerical study was conducted using Fluent to understand the influence of uneven inlet flow. The results showed that uneven inlet flow significantly affects the size and distribution of unsteady pulses on the rotor blades, which cause regular, periodic changes as the rotor blades rotate. Interactions between rotor blades and inlet unevenness were observed via the POD method as well. The discussion of the circumferential modes from aerodynamic noise of an axial flow cooling fan can act as a reference for further cooling fan noise reduction measures.

Aerodynamic noise characteristics of airfoils with morphed trailing edges

2022 ◽  
Vol 93 ◽  
pp. 108892
Author(s):  
Hasan Kamliya Jawahar ◽  
SH. S. Vemuri ◽  
Mahdi Azarpeyvand
Keyword(s):  
Aerodynamic Noise ◽  
Noise Characteristics ◽  
Trailing Edges

Numerical simulation of aeroacoustic noise from landing gear and rectangular cavity

2020 ◽  
Vol 234 (7) ◽  
pp. 1259-1271
Author(s):  
Zhifei Guo ◽  
Peiqing Liu ◽  
Jin Zhang ◽  
Hao Guo
Keyword(s):  
Numerical Simulation ◽  
Low Frequency ◽  
Landing Gear ◽  
Rectangular Cavity ◽  
Cavity Resonance ◽  
Aerodynamic Noise ◽  
Frequency Noise ◽  
Radiation Mechanism ◽  
Ansys Fluent ◽  
Aeroacoustic Noise

This paper is aimed at researching the interaction between aeroacoustic noise radiated from a rectangular cavity (gear bay) and from landing gear. It is a complicated flow-induced noise problem, involving the nonlinear, unsteady evolution of the turbulent structure inside the airflow bypassing the landing gear and the cavity. The generation and radiation mechanism of aeroacoustic noise are also concerned. In fact, it is a problem about the nonlinear interaction between the vortices shedding from the boundary layer of bluff bodies and the cavity-limited shear layer. To simplify this issue, a two-wheel landing gear named LAGOON is chosen as the landing gear model. The unsteady flow field and aerodynamic noise from it is simulated by applying the commercial software ANSYS Fluent. Good agreement is achieved between the numerical simulation and wind tunnel measurements in terms of the aerodynamic and aeroacoustic results. According to the size of LAGOON, a simple rectangular cavity is designed as the landing gear bay. Both the cavity combined with LAGOON and the cavity alone are simulated and compared. The results show that under the blocking effect of a strut, most small pieces of vortices at the trailing edge of the cavity bottom would dissipate rather than move forward along with the backflow, leading to the correlation of cavity resonance being more contrasting and increasing its amplitude. The blockage effect induced by rear wall could also enhance the turbulence kinetic energy at the wake of the strut, thus increasing the low-frequency noise radiated from the strut and cavity.

Aerodynamic noise numerical simulation and noise reduction study on automobile alternator

2017 ◽  
Vol 31 (5) ◽  
pp. 2047-2055 ◽  
Author(s):  
Chunrong Hua ◽  
Yadong Zhang ◽  
Dawei Dong ◽  
Bin Yan ◽  
Huajiang Ouyang
Keyword(s):  
Numerical Simulation ◽  
Noise Reduction ◽  
Aerodynamic Noise

Numerical simulation of aerodynamic noise and noise reduction of range hood

2021 ◽  
Vol 175 ◽  
pp. 107806
Author(s):  
Jia-yu Huang ◽  
Kai Zhang ◽  
Hai-yun Li ◽  
An-ran Wang ◽  
Mingyue Yang
Keyword(s):  
Numerical Simulation ◽  
Noise Reduction ◽  
Aerodynamic Noise

The Application of Numerical Simulation Technology in the External Aerodynamic Noise Field of High-Speed Train

2011 ◽  
Vol 101-102 ◽  
pp. 197-201 ◽  
Author(s):  
Zhen Gyu Zheng ◽  
Ren Xian Li
Keyword(s):  
Numerical Simulation ◽  
Boundary Condition ◽  
High Speed ◽  
Aerodynamic Noise ◽  
Dipole Source ◽  
Center Line ◽  
High Speed Train ◽  
Noise Field ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Pressure

This paper utilized the Boundary Element Method (BEM) combined with the Computational Fluid Dynamics (CFD) based on Lighthill’s analogy in the high-speed train model, and converted the fluctuating flow pressure near the vehicle’s surface into the dipole source boundary condition in acoustics grid, eventually succeeded in completing the numerical simulation of aerodynamic noise field outside the high-speed train by introducing the dipole source boundary condition into the train BEM model. The results show that the main aerodynamic noise controlling area is 15-20 meters away from the track center line in the horizontal direction, and the Sound Press Level (SPL) is 63-72dB.

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