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Full-Text Articles in Physical Sciences and Mathematics
Theory And Estimation Of Acoustic Intensity And Energy Density, Derek C. Thomas
Theory And Estimation Of Acoustic Intensity And Energy Density, Derek C. Thomas
Theses and Dissertations
In order to facilitate the acquisition and accurate interpretation of intensity and energy density data in high-amplitude pressure fields, the expressions for intensity and energy density are examined to ascertain the impact of nonlinear processes on the standard expressions. Measurement techniques for estimating acoustic particle velocity are presented. The finite-difference method is developed in an alternate manner and presented along with bias and confidence estimates. Additionally, two new methods for estimating the local particle velocity are presented. These methods appears to eliminate the errors and bias associated with the finite-difference technique for certain cases.
Error Sensor Strategies For Active Noise Control And Active Acoustic Equalization In A Free Field, Ryan T. Chester
Error Sensor Strategies For Active Noise Control And Active Acoustic Equalization In A Free Field, Ryan T. Chester
Theses and Dissertations
Several measurements may be used as error signals to determine how to appropriately control a sound field. These include pressure, particle velocity, energy density and intensity. In this thesis, numerical models are used to show which signals perform best in is free-field active noise control (ANC) using error sensors located in the near field of the sound sources. The second is equalization in a free field and a semi-free field. Minimized energy density total power output (MEDToPO) plots are developed; these indicate the maximum achievable attenuation for a chosen error sensor as a function of location. A global listening area …