scholarly journals Active control of the sound power scattered by a locally-reacting sphere

2020 ◽  
Vol 147 (3) ◽  
pp. 1851-1862
Author(s):  
Stephen J. Elliott ◽  
Mihai Orita ◽  
Jordan Cheer
Keyword(s):  
Active Control ◽  
Sound Power

Active control of compressor noise in the machinery room of refrigerators

2019 ◽  
Vol 67 (5) ◽  
pp. 350-362
Author(s):  
J. M. Ku ◽  
W. B. Jeong ◽  
C. Hong
Keyword(s):  
Control System ◽  
Active Control ◽  
Weighting Function ◽  
Reference Signal ◽  
Active Noise Control ◽  
Dominant Frequency ◽  
Time Signal ◽  
Frequency Noise ◽  
Sound Power ◽  
Fxlms Algorithm

The low-frequency noise generated by the vibration of the compressor in the machinery room of refrigerators is considered as annoying sound. Active noise control is used to reduce this noise without any change in the design of the compressor in the machinery room. In configuring the control system, various signals are measured and analyzed to select the reference signal that best represents the compressor noise. As the space inside the machinery room is small, the size of a speaker is limited, and the magnitude of the controller transfer function is designed to be small at low frequencies, the controller uses FIR filter structure converged by the FxLMS algorithm using the pre-measured time signal. To manage the convergence speed for each frequency, the frequency-weighting function is applied to FxLMS algorithm. A series of measurements are performed to design the controller and to evaluate the control performance. After the control, the sound power transmitted by the refrigerator is reduced by 9 dB at the first dominant frequency (408 Hz in this case) and 3 dB at the second dominant frequency (459 Hz here), and the overall sound power decreases by 2.6 dB. Through this study, an active control system for the noise generated by refrigerator compressors is established.

Passive and Active Control of the Radiated Sound Power from a Submarine Excited by Propeller Forces

2013 ◽  
Vol 57 (1) ◽  
pp. 59-71 ◽  
Author(s):  
Sascha Merz ◽  
Nicole Kessissoglou ◽  
Roger Kinns ◽  
Steffen Marburg
Keyword(s):  
Active Control ◽  
Sound Power ◽  
Radiated Sound ◽  
Radiated Sound Power

Active control of sound power using acoustic basis functions

1993 ◽  
Vol 94 (3) ◽  
pp. 1816-1816
Author(s):  
Koorosh Naghshineh ◽  
Gary H. Koopmann
Keyword(s):  
Active Control ◽  
Basis Functions ◽  
Sound Power

Active Control of Low-Frequency Sound Radiation From Vibrating Panel Using Planar Sound Sources

2001 ◽  
Vol 124 (1) ◽  
pp. 2-9 ◽  
Author(s):  
Kean Chen ◽  
Gary H. Koopmann
Keyword(s):  
Active Control ◽  
Near Field ◽  
Low Frequency ◽  
Sound Radiation ◽  
Sound Field ◽  
Sound Power ◽  
Frequency Range ◽  
Sound Sources ◽  
Frequency Sound ◽  
Secondary Sources

Active control of low frequency sound radiation using planar secondary sources is theoretically investigated in this paper. The primary sound field originates from a vibrating panel and the planar sources are modeled as simply supported rectangular panels in an infinite baffle. The sound power of the primary and secondary panels are calculated using a near field approach, and then a series of formulas are derived to obtain the optimum reduction in sound power based on minimization of the total radiate sound power. Finally, active reduction for a number of secondary panel arrangements is examined and it is concluded that when the modal distribution of the secondary panel does not coincide with that of the primary panel, one secondary panel is sufficient. Otherwise four secondary panels can guarantee considerable reduction in sound power over entire frequency range of interest.

ACTIVE CONTROL OF A MACHINE SUSPENSION SYSTEM SUPPORTED ON A CYLINDRICAL SHELL

2013 ◽  
Vol 21 (03) ◽  
pp. 1350012
Author(s):  
X. LIU ◽  
G. JIN ◽  
Y. WANG ◽  
Y. SHI ◽  
X. FENG
Keyword(s):  
Cylindrical Shell ◽  
Numerical Simulations ◽  
Active Control ◽  
Numerical Study ◽  
Control Strategies ◽  
Acoustic Power ◽  
Suspension System ◽  
Sound Power ◽  
Control Force ◽  
Power Minimization

A numerical study on the active control of a machine suspension system supported on a cylindrical shell aiming to reduce the sound radiation is presented in this paper. In this system, a rigid-body machine is supported on a simply-supported elastic cylindrical shell through four active isolators. A theoretical model is employed and four types of active control strategies including kinetic energy minimization strategy, power flow minimization strategy, squared acceleration minimization strategy and acoustic power minimization strategy are considered, with corresponding active control force obtained by linear quadratic optimal method. Numerical simulations are conducted and detailed results were presented. Active control performance under these four control strategies is compared and analyzed in terms of radiated sound power, and the effect of the number of active actuators is discussed by numerical analysis. The results show that acoustic power minimization strategy has the best performance to reduce the sound power radiated from supporting shell in general. Through numerical simulations, some comprehensive design principles of active control system are discussed at the end.

Use of acoustic basis functions for active control of sound power radiated from a cylindrical shell

1998 ◽  
Vol 103 (4) ◽  
pp. 1897-1903 ◽  
Author(s):  
Koorosh Naghshineh ◽  
Weicheng Chen ◽  
Gary H. Koopmann
Keyword(s):  
Cylindrical Shell ◽  
Active Control ◽  
Basis Functions ◽  
Sound Power

Active control of source sound power in uniform flow

1996 ◽  
Author(s):  
P. Joseph ◽  
C. Morfey ◽  
P. Nelson
Keyword(s):  
Active Control ◽  
Uniform Flow ◽  
Sound Power

Active Control of the Structural and Acoustic Responses of a Fluid-Loaded Plate; Part II: Feedforward control

1998 ◽  
Vol 17 (2) ◽  
pp. 99-115 ◽  
Author(s):  
Nicole J. Kessissoglou ◽  
Jie Pan
Keyword(s):  
Control Systems ◽  
Active Control ◽  
Sound Pressure ◽  
Feedforward Control ◽  
Sound Power ◽  
Plate Vibration ◽  
Fluid Loading ◽  
Loaded Plate ◽  
Loaded Structure ◽  
Acoustic Responses

Attenuation of the structural and acoustic fields associated with a fluid-loaded plate can be achieved with the application of active control to the vibrating structure. For a heavily fluid-loaded structure, the fluid-structure interaction will significantly affect the wave propagation in the structure, as well as the nature of-the sound radiation from the structure into the fluid field. In this paper, two active control systems are applied to the plate to attenuate the structural and acoustic responses. An active structural acoustic control (ASAC) system is designed using feedforward techniques to attenuate the far-field radiating sound power and local sound pressure. Feedforward control laws are also developed for the minimisation of the plate vibration. Under both heavy and light fluid-loading conditions, the performances of the active control systems are examined by comparing the uncontrolled and controlled sound power, sound pressure and plate vibration. The nature of the fluid-loading on the performance of the control systems is also investigated.

Sign in / Sign up

Export Citation Format

Share Document