Estimation of parametric sound field controlled by source amplitudes and phases using numerical simulation

2012 ◽  
Author(s):  
Hideyuki Nomura ◽  
Claes M. Hedberg ◽  
Tomoo Kamakura
2013 ◽  
Vol 444-445 ◽  
pp. 462-467
Author(s):  
Dang Guo Yang ◽  
Yong Hang Wu ◽  
Jin Min Liang ◽  
Jun Liu

A numerical simulation method on noise prediction, which incorporates aerodynamics and sound wave equations based on acoustic analogy, is presented in the paper. Near-field unsteady aerodynamic characteristic can be obtain by large eddy simulation (LES), and far-field propagation of sound waves and spatial sound-field can be obtain by solving the time-domain integral equations of Ffowcs Williams and Hawings (FW-H). Based on the method, a numerical simulation was done on a two-dimension cylinder and a three-dimension flat plate with blunt leading edge. The agreement of numerical results with experiment data validated the Feasibility of the method. The results also indicate that LES can describe vortex generation and shedding in the flow-fields, and FW-H formulation, which has taken time-lag between sound emission and reception times into account, can simulate time-effect of sound propagation toward far-fields.


Author(s):  
Dandy Eschricht ◽  
Ulf Michel ◽  
Frank Thiele ◽  
Marco Rose

AIAA Journal ◽  
2004 ◽  
Vol 42 (10) ◽  
pp. 2028-2034 ◽  
Author(s):  
Y. Özyörük ◽  
V. Ahuja

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1777 ◽  
Author(s):  
Wang ◽  
Liu ◽  
Wang ◽  
Zhou ◽  
Jiang ◽  
...  

To study the influence of the turbulence model on the sound field of pumps, the standard k-ε, Re-normalization Group (RNG) k-ε and Shear Stress Transfer (SST) k-ω models were employed to simulate flow and sound fields of a five-stage centrifugal pump with a vaned-diffuser. The vibration characteristics of the pump were simulated with the modal response method. A vibration experiment in the pump was carried out to verify the feasibility of the numerical simulation of the hydrodynamic noise in the pump. Results show that in the spectrum of internal and external noise, the peak value appears at axial passing frequency (APF) and its harmonic frequency. Compared with the standard k-ε model, the RNG k-ε and SST k-ω models show good consistence with the noise characteristics of experimental results, indicating the characteristic frequency and revealing the approximate behavior of the sound field in the pump. In general, the simulation of the sound field based on the RNG k-ε model is most appropriate for the multistage centrifugal pump with a vaned-diffuser.


Author(s):  
H B Zhang ◽  
W K Jiang ◽  
Z Y Huang ◽  
Q Wan

The nearfield acoustic holography (NAH) method based on the wave superposition algorithm (WSA) assumes that the sound field is induced by a series of simple sources inside the vibrational object boundary. The sound field can be reconstructed after the strength of virtual sources is determined in an inverse procedure. The theory, numerical simulation, and application of WSA-based NAH is often concerned with the simple sources. In practice, the vibrational objects are more complicated and sometimes should even be treated as multiple separated objects. The reconstruction of a sound field by using conventional WSA-based NAH directly is not satisfactory. In the presented modified WSA-based NAH, complicated vibrational objects are separated into several parts and looked at as independent components. Whole sound fields are generated by all these components. The comparisons between conventional and modified WSA-based NAH are carried out through numerical simulations. It shows that the more accurate result is obtained by applying the modified WSA-based NAH to the complicated objects. An experiment of a compressor with complicated structures is conducted to illustrate the validity of modified WSA-based NAH.


2015 ◽  
Vol 727-728 ◽  
pp. 831-834
Author(s):  
Yue Fu ◽  
Chao Lu ◽  
Guo Chen ◽  
Chan Wang

The numerical simulation of immersion TOFD (I-TOFD) detection for low thicknesses pipe ring weld was performed by Ultrasonic simulation software Wave 3000. The author get the sound field characteristics of diffraction wave through setting eight receivers in receiving area, thus determine the strongest diffraction wave energy range between 50°~60°.In the simulation, the author found that the longitudinal wave inspired by source after refraction in water-steel interface, continue to spread along under the surface of water-steel interface, and then the wave go back to the water again. We call the wave as the lateral wave of I-TOFD. So the defects can be determined according to the lateral wave and the bottom echo wave. The result of numerical simulation verified the feasibility of using I-TOFD method in detecting low thicknesses pipe ring weld in theory.


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