Topic
Acoustic radiation
About: Acoustic radiation is a research topic. Over the lifetime, 1954 publications have been published within this topic receiving 26931 citations. The topic is also known as: geniculotemporal fibres & geniculotemporal fibers.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, the authors present microparticle image velocimetry measurements of suspended microparticles of diameters from 0.6 to 10 μm undergoing acoustophoresis in an ultrasound symmetry plane in a microchannel, and they predict theoretically and confirm experimentally that the ratio between the acoustic radiation and streaming-induced particle velocities is proportional to the actuation frequency, the acoustic contrast factor, and the square of the particle size.
Abstract: We present microparticle image velocimetry measurements of suspended microparticles of diameters from 0.6 to 10 μm undergoing acoustophoresis in an ultrasound symmetry plane in a microchannel. The motion of the smallest particles is dominated by the Stokes drag from the induced acoustic streaming flow, while the motion of the largest particles is dominated by the acoustic radiation force. For all particle sizes we predict theoretically how much of the particle velocity is due to radiation and streaming, respectively. These predictions include corrections for particle-wall interactions and ultrasonic thermoviscous effects and match our measurements within the experimental uncertainty. Finally, we predict theoretically and confirm experimentally that the ratio between the acoustic radiation- and streaming-induced particle velocities is proportional to the actuation frequency, the acoustic contrast factor, and the square of the particle size, while it is inversely proportional to the kinematic viscosity.
214 citations
TL;DR: In this article, active control of sound radiation from vibrating plates by oscillating forces applied directly to the structure is analytically studied, and it is shown that global attenuation of broadband radiated sound levels for low to mid-range frequencies can be achieved with one or two control forces, irrespective of whether the system is on or off resonance.
197 citations
TL;DR: In this article, the acoustic radiation efficiency σ of a rectangular panel that undergoes time-harmonic transverse oscillations with sinusoidal mode shapes is estimated when the acoustic wavenumber and the platewavenumber components are large.
Abstract: The acoustic radiation efficiency σ of a rectangular panel that undergoes time-harmonic transverse oscillations with sinusoidal mode shapes is estimated when the acoustic wavenumber and the plate wavenumber components are large. The results confirm that σ has different asymptotic forms in different regions of plate wavenumber space. Results are given for each region, together with transition formulae near the various connecting boundaries. Some earlier results are confirmed, modified and extended.
195 citations
TL;DR: It is shown in both simulation results and noise test that the electromagnetic force due to slotting effects contributes the most remarkable component to the overall noise.
Abstract: A detailed analysis of electromagnetic noise in external rotor permanent-magnet synchronous motors is presented in this paper. First, the spatial distribution and frequency characteristics of the electromagnetic force acting on the surface of the permanent magnet are discussed. Then, calculation models for electromagnetic force, structural vibration, and acoustic radiation are developed to predict noise by taking an external rotor in-wheel motor as example. The uneven distribution of electromagnetic force on the surface of the permanent magnet is taken into account by means of loading nodal force into the structural model which is verified by modal test. Through the mode superposition method, the vibration on the surface of the outer rotor is calculated, and the acoustic boundary element method is used to predict the acoustic radiation. Noise test is conducted to validate the simulated noise. It is shown in both simulation results and noise test that the electromagnetic force due to slotting effects contributes the most remarkable component to the overall noise. Finally, slot opening width is optimized to reduce the amplitude of magnetic force close to resonance frequencies, and the overall sound pressure level decreases by 6 dB(A) after optimization.
174 citations
TL;DR: In this article, the authors applied the method of Gor'kov for deriving the acoustic radiation potential on a sphere in an arbitrary sound field and derived generalized potential and force expressions for arbitrary standing wave modes in rectangular, cylindrical, and spherical geometries for the case where the sphere radius is much smaller than the wavelength.
Abstract: The method of Gor'kov is applied for deriving the acoustic radiation potential on a sphere in an arbitrary sound field. Generalized potential and force expressions are derived for arbitrary standing wave modes in rectangular, cylindrical, and spherical geometries for the case where the sphere radius is much smaller than the wavelength. Criteria for determining radiation-potential minima are derived and examples of characteristic spatial radiation-potential profiles are presented. Single modes that can sustain stable positioning are discussed for each geometry. The localizing force strengths for representative standing wave modes in the three geometries are also compared. The positioning of samples due to acoustic forces only are considered. However, the method developed is general and is extended to include gravity or other external forces.
174 citations