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Articles 1 - 3 of 3
Full-Text Articles in Mechanical Engineering
Design Of Broadband Helmholtz Resonator Arrays Using The Radiation Impedance Method, Vidhya Rajendran, Andy Piacsek, Tomás Méndez Echenagucia
Design Of Broadband Helmholtz Resonator Arrays Using The Radiation Impedance Method, Vidhya Rajendran, Andy Piacsek, Tomás Méndez Echenagucia
All Faculty Scholarship for the College of the Sciences
This paper describes the design process of a low-frequency sound absorptive panel composed of differently tuned Helmholtz resonators (HRs), considering size and fabrication constraints relevant for applications in the building sector. The paper focuses on cylindrical and spiral resonators with embedded necks that are thin and can achieve high absorption. the mutual interaction between the resonators was modeled based on the radiation impedance method and it plays a key component in enhancing the absorption performance of the array. The differential evolution search algorithm was used to design the resonators and modify their mutual interaction to derive the absorption performance of …
Resonance Frequencies Of A Spherical Aluminum Shell Subject To Static Internal Pressure, Andrew A. Piacsek, Sami Abdul-Wahid, Robert Taylor
Resonance Frequencies Of A Spherical Aluminum Shell Subject To Static Internal Pressure, Andrew A. Piacsek, Sami Abdul-Wahid, Robert Taylor
All Faculty Scholarship for the College of the Sciences
Measurements of the vibrational response of a spherical aluminum shell subject to changes in the interior pressure clearly demonstrate that resonance frequencies shift higher as the pressure is increased. The frequency shift appears to be smaller for longitudinal modes than for bending wave modes. The magnitude of frequency shift is comparable to analytical predictions made for thin cylindrical shells. Changes in the amplitudes of resonance peaks are also observed. A possible application of this result is a method for noninvasively monitoring pressure changes inside sealed containers, including intracranial pressure in humans.
Nonlinear Progressive Wave Equation For Stratified Atmospheres, B. Edward Mcdonald, Andrew A. Piacsek
Nonlinear Progressive Wave Equation For Stratified Atmospheres, B. Edward Mcdonald, Andrew A. Piacsek
All Faculty Scholarship for the College of the Sciences
The nonlinear progressive wave equation (NPE) [McDonald and Kuperman, J. Acoust. Soc. Am. 81, 1406–1417 (1987)] is expressed in a form to accommodate changes in the ambient atmospheric density, pressure, and sound speed as the time-stepping computational window moves along a path possibly traversing significant altitude differences (in pressure scale heights). The modification is accomplished by the addition of a stratification term related to that derived in the 1970s for linear range-stepping calculations and later adopted into Khokhlov-Zabolotskaya-Kuznetsov-type nonlinear models. The modified NPE is shown to preserve acoustic energy in a ray tube and yields analytic similarity solutions for …