Elastic wave interaction coefficients were defined in the case of arbitrary n-th order nonlinearity and calculated explicitly in cases of quadratically and cubically nonlinear interactions. In the first case the isotropic Murnaghan material, and the cubic crystal of class m3m were analyzed. The calculated coefficients were displayed graphically in the form of tables which reveal the difference in behavior of shear elastic waves for isotropic and anisotropic materials. In the isotropic case there is no quadratically nonlinear coupling between propagating collinearly shear waves and the appropriate coefficients disappear. In the anisotropic case there are special directions along which such a coupling takes place and the coefficients responsible for this coupling are not equal to zero. Moreover, choosing a particular direction of propagation, namely a three-fold symmetry acoustic axis, (e.g. [111] direction in a cubic crystal) results in a a very special symmetry among these coefficients. Besides, the cubically nonlinear interaction coefficients were calculated for a model of a soft solid.Elastic wave interaction coefficients were defined in the case of arbitrary n-th order nonlinearity and calculated explicitly in cases of quadratically and cubically nonlinear interactions. In the first case the isotropic Murnaghan material, and the cubic crystal of class m3m were analyzed. The calculated coefficients were displayed graphically in the form of tables which reveal the difference in behavior of shear elastic waves for isotropic and anisotropic materials. In the isotropic case there is no quadratically nonlinear coupling between propagating collinearly shear waves and the appropriate coefficients disappear. In the anisotropic case there are special directions along which such a coupling takes place and the coefficients responsible for this coupling are not equal to zero. Moreover, choosing a particular direction of propagation, namely a three-fold symmetry acoustic axis, (e.g. [111] direction in a cubic crystal) results in a a very special symmetry among these coefficients. Besides, the cubic...
{"title":"On nonlinearity parameters describing elastic wave interactions","authors":"W. Domański","doi":"10.1121/2.0000898","DOIUrl":"https://doi.org/10.1121/2.0000898","url":null,"abstract":"Elastic wave interaction coefficients were defined in the case of arbitrary n-th order nonlinearity and calculated explicitly in cases of quadratically and cubically nonlinear interactions. In the first case the isotropic Murnaghan material, and the cubic crystal of class m3m were analyzed. The calculated coefficients were displayed graphically in the form of tables which reveal the difference in behavior of shear elastic waves for isotropic and anisotropic materials. In the isotropic case there is no quadratically nonlinear coupling between propagating collinearly shear waves and the appropriate coefficients disappear. In the anisotropic case there are special directions along which such a coupling takes place and the coefficients responsible for this coupling are not equal to zero. Moreover, choosing a particular direction of propagation, namely a three-fold symmetry acoustic axis, (e.g. [111] direction in a cubic crystal) results in a a very special symmetry among these coefficients. Besides, the cubically nonlinear interaction coefficients were calculated for a model of a soft solid.Elastic wave interaction coefficients were defined in the case of arbitrary n-th order nonlinearity and calculated explicitly in cases of quadratically and cubically nonlinear interactions. In the first case the isotropic Murnaghan material, and the cubic crystal of class m3m were analyzed. The calculated coefficients were displayed graphically in the form of tables which reveal the difference in behavior of shear elastic waves for isotropic and anisotropic materials. In the isotropic case there is no quadratically nonlinear coupling between propagating collinearly shear waves and the appropriate coefficients disappear. In the anisotropic case there are special directions along which such a coupling takes place and the coefficients responsible for this coupling are not equal to zero. Moreover, choosing a particular direction of propagation, namely a three-fold symmetry acoustic axis, (e.g. [111] direction in a cubic crystal) results in a a very special symmetry among these coefficients. Besides, the cubic...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87664583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarah Cleve, Matthieu Guédra, C. Mauger, C. Inserra, P. Blanc-Benon
Microbubbles exposed to a sufficiently strong ultrasound field can show nonspherical oscillations called surface modes. In the vicinity of the bubble surface, these oscillations induce a slow mean flow named microstreaming. Microstreaming plays an important role in medical applications such as sonoporation as well as in engineering applications such as micromixing. A better understanding of the induced flows will hence be beneficial to a large number of applications. Recent studies mainly report on microstreaming induced by bubbles resting on a solid boundary. The observation of microstreaming around a single, free bubble is challenging, because several experimental difficulties have to be overcome: Avoidance of translational instabilities, obtainment of a steady-state behavior maintaining surface modes, correct choice of tracer particles, and correlation between fast temporal bubble dynamics and relatively slow microstreaming. We present an experimental setup, that accomplishes the simultaneous visualiza...
{"title":"Experimental investigation of microstreaming induced by free nonspherically oscillating microbubbles","authors":"Sarah Cleve, Matthieu Guédra, C. Mauger, C. Inserra, P. Blanc-Benon","doi":"10.1121/2.0000900","DOIUrl":"https://doi.org/10.1121/2.0000900","url":null,"abstract":"Microbubbles exposed to a sufficiently strong ultrasound field can show nonspherical oscillations called surface modes. In the vicinity of the bubble surface, these oscillations induce a slow mean flow named microstreaming. Microstreaming plays an important role in medical applications such as sonoporation as well as in engineering applications such as micromixing. A better understanding of the induced flows will hence be beneficial to a large number of applications. Recent studies mainly report on microstreaming induced by bubbles resting on a solid boundary. The observation of microstreaming around a single, free bubble is challenging, because several experimental difficulties have to be overcome: Avoidance of translational instabilities, obtainment of a steady-state behavior maintaining surface modes, correct choice of tracer particles, and correlation between fast temporal bubble dynamics and relatively slow microstreaming. We present an experimental setup, that accomplishes the simultaneous visualiza...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82343624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A soil plate oscillator (SPO) apparatus consists of two circular flanges sandwiching and clamping a thin circular elastic plate. The apparatus can model the acoustic landmine detection problem. Uniform spherical glass beads – representing a nonlinear mesoscopic elastic material – are supported at the bottom by the acrylic plate (4.5 inch diam, 1/8 inch thick) and stiff cylindrical sidewalls of the upper flange. A magnetic disk centered and fastened below the plate is driven by an AC coil placed below the magnet. Nonlinear tuning curves of the magnet’s acceleration are measured by driving the coil with a swept sinusoidal signal applied to a constant current amplifier. In two-tone tests, air-borne sound from 3 inch diameter speakers drive the bead column surface at closely spaced frequencies near the fundamental resonance. Nonlinearly generated combination frequency tones are compared for each of the bead diameter experiments.A soil plate oscillator (SPO) apparatus consists of two circular flanges sandwiching and clamping a thin circular elastic plate. The apparatus can model the acoustic landmine detection problem. Uniform spherical glass beads – representing a nonlinear mesoscopic elastic material – are supported at the bottom by the acrylic plate (4.5 inch diam, 1/8 inch thick) and stiff cylindrical sidewalls of the upper flange. A magnetic disk centered and fastened below the plate is driven by an AC coil placed below the magnet. Nonlinear tuning curves of the magnet’s acceleration are measured by driving the coil with a swept sinusoidal signal applied to a constant current amplifier. In two-tone tests, air-borne sound from 3 inch diameter speakers drive the bead column surface at closely spaced frequencies near the fundamental resonance. Nonlinearly generated combination frequency tones are compared for each of the bead diameter experiments.
{"title":"Nonlinear tuning curve and two-tone tests using glass beads vibrating over clamped elastic plate","authors":"Emily V. Santos, M. Korman","doi":"10.1121/2.0000896","DOIUrl":"https://doi.org/10.1121/2.0000896","url":null,"abstract":"A soil plate oscillator (SPO) apparatus consists of two circular flanges sandwiching and clamping a thin circular elastic plate. The apparatus can model the acoustic landmine detection problem. Uniform spherical glass beads – representing a nonlinear mesoscopic elastic material – are supported at the bottom by the acrylic plate (4.5 inch diam, 1/8 inch thick) and stiff cylindrical sidewalls of the upper flange. A magnetic disk centered and fastened below the plate is driven by an AC coil placed below the magnet. Nonlinear tuning curves of the magnet’s acceleration are measured by driving the coil with a swept sinusoidal signal applied to a constant current amplifier. In two-tone tests, air-borne sound from 3 inch diameter speakers drive the bead column surface at closely spaced frequencies near the fundamental resonance. Nonlinearly generated combination frequency tones are compared for each of the bead diameter experiments.A soil plate oscillator (SPO) apparatus consists of two circular flanges sandwiching and clamping a thin circular elastic plate. The apparatus can model the acoustic landmine detection problem. Uniform spherical glass beads – representing a nonlinear mesoscopic elastic material – are supported at the bottom by the acrylic plate (4.5 inch diam, 1/8 inch thick) and stiff cylindrical sidewalls of the upper flange. A magnetic disk centered and fastened below the plate is driven by an AC coil placed below the magnet. Nonlinear tuning curves of the magnet’s acceleration are measured by driving the coil with a swept sinusoidal signal applied to a constant current amplifier. In two-tone tests, air-borne sound from 3 inch diameter speakers drive the bead column surface at closely spaced frequencies near the fundamental resonance. Nonlinearly generated combination frequency tones are compared for each of the bead diameter experiments.","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89267014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper investigates acoustic levitation and noncontact transportation techniques for use with planar objects. An acoustic levitation system was developed that consists of a 1-mm-thick and 400-mm-long bending plate along with two bolt-clamped Langevin-type transducers (BLTs) that have stepped horns. A plane reflector was installed parallel to the vibrating plate to generate an ultrasound standing wave between the reflector and the plate. A planar object was levitated along the nodal line of the acoustic standing wave in the waveguide, and that affected the sound pressure distribution around the plate. The sound pressure distribution in the ultrasound waveguide was calculated via finite element analysis to investigate the effects of levitation of a planar object in the standing wave field. The (3, 1) resonance mode with a wavelength of approximately 15 mm in the x direction was excited in the air layer above and below the planar object. The acoustic field in the waveguide was sensitive to the length of the planar object, and several peaks occurred in the sound pressure amplitude when the half-wavelength resonance mode in the z direction was generated in the waveguide, indicating that there were suitable lengths of the plate for the acoustic levitation.This paper investigates acoustic levitation and noncontact transportation techniques for use with planar objects. An acoustic levitation system was developed that consists of a 1-mm-thick and 400-mm-long bending plate along with two bolt-clamped Langevin-type transducers (BLTs) that have stepped horns. A plane reflector was installed parallel to the vibrating plate to generate an ultrasound standing wave between the reflector and the plate. A planar object was levitated along the nodal line of the acoustic standing wave in the waveguide, and that affected the sound pressure distribution around the plate. The sound pressure distribution in the ultrasound waveguide was calculated via finite element analysis to investigate the effects of levitation of a planar object in the standing wave field. The (3, 1) resonance mode with a wavelength of approximately 15 mm in the x direction was excited in the air layer above and below the planar object. The acoustic field in the waveguide was sensitive to the length of ...
{"title":"Acoustic field around a planar object levitated in an ultrasound waveguide","authors":"Kentaro Masuda, D. Koyama, M. Matsukawa","doi":"10.1121/2.0000890","DOIUrl":"https://doi.org/10.1121/2.0000890","url":null,"abstract":"This paper investigates acoustic levitation and noncontact transportation techniques for use with planar objects. An acoustic levitation system was developed that consists of a 1-mm-thick and 400-mm-long bending plate along with two bolt-clamped Langevin-type transducers (BLTs) that have stepped horns. A plane reflector was installed parallel to the vibrating plate to generate an ultrasound standing wave between the reflector and the plate. A planar object was levitated along the nodal line of the acoustic standing wave in the waveguide, and that affected the sound pressure distribution around the plate. The sound pressure distribution in the ultrasound waveguide was calculated via finite element analysis to investigate the effects of levitation of a planar object in the standing wave field. The (3, 1) resonance mode with a wavelength of approximately 15 mm in the x direction was excited in the air layer above and below the planar object. The acoustic field in the waveguide was sensitive to the length of the planar object, and several peaks occurred in the sound pressure amplitude when the half-wavelength resonance mode in the z direction was generated in the waveguide, indicating that there were suitable lengths of the plate for the acoustic levitation.This paper investigates acoustic levitation and noncontact transportation techniques for use with planar objects. An acoustic levitation system was developed that consists of a 1-mm-thick and 400-mm-long bending plate along with two bolt-clamped Langevin-type transducers (BLTs) that have stepped horns. A plane reflector was installed parallel to the vibrating plate to generate an ultrasound standing wave between the reflector and the plate. A planar object was levitated along the nodal line of the acoustic standing wave in the waveguide, and that affected the sound pressure distribution around the plate. The sound pressure distribution in the ultrasound waveguide was calculated via finite element analysis to investigate the effects of levitation of a planar object in the standing wave field. The (3, 1) resonance mode with a wavelength of approximately 15 mm in the x direction was excited in the air layer above and below the planar object. The acoustic field in the waveguide was sensitive to the length of ...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77482566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The study of nonlinear sustained oscillations in ducts requires taking into account a variety of relevant physical phenomena, which may occur at different scales, and which therefore are described by different fluid dynamics regimes. In the present work the joint effect of these phenomena is investigated by means of numerical simulation, using a full-wave finite volume method (FiVoNAGI) over a 2D spatial domain assuming axial symmetry, which includes nonlinear propagation and thermoviscous attenuation over a wide range of scales. Excitation at one end of a straight cylindrical tube, open at the other end, is provided by a nonlinear feedback mechanism. First, a transitory state is observed, which is finally followed by a sustained-oscillation state with a self-regulated resonance frequency. For sufficiently large values of the excitation amplitude, shock waves are formed, and their development can be analyzed in terms of progressive waves. The results obtained reproduce qualitatively some well-known featur...
{"title":"Numerical study of nonlinear sustained oscillations in a cylindrical open-ended tube","authors":"P. Rendón, R. Velasco-Segura","doi":"10.1121/2.0000892","DOIUrl":"https://doi.org/10.1121/2.0000892","url":null,"abstract":"The study of nonlinear sustained oscillations in ducts requires taking into account a variety of relevant physical phenomena, which may occur at different scales, and which therefore are described by different fluid dynamics regimes. In the present work the joint effect of these phenomena is investigated by means of numerical simulation, using a full-wave finite volume method (FiVoNAGI) over a 2D spatial domain assuming axial symmetry, which includes nonlinear propagation and thermoviscous attenuation over a wide range of scales. Excitation at one end of a straight cylindrical tube, open at the other end, is provided by a nonlinear feedback mechanism. First, a transitory state is observed, which is finally followed by a sustained-oscillation state with a self-regulated resonance frequency. For sufficiently large values of the excitation amplitude, shock waves are formed, and their development can be analyzed in terms of progressive waves. The results obtained reproduce qualitatively some well-known featur...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89614168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Gee, Kyle G. Miller, Brent O. Reichman, Alan T. Wall
Characterization of far-field jet noise spectral evolution can be performed locally with a single microphone measurement using a gain factor that stems from the ensemble-averaged, frequency-domain version of the generalized Burgers equation. The factor quantifies the nonlinear change in the sound pressure level spectrum over distance [B. O. Reichman et al., J. Acoust. Soc. Am. 139, 2505-2513 (2016)]. Here, noise waveforms from a high-performance military jet aircraft are characterized with this gain factor and compared to propagation losses from geometric spreading and atmospheric absorption. Far-field results show that the high-frequency nonlinear gains at high frequencies tend to balance the absorption losses, thus establishing the characteristic spectral slope present in shock-containing noise. Differences as a function of angle, distance, and engine condition are explored.Characterization of far-field jet noise spectral evolution can be performed locally with a single microphone measurement using a gain factor that stems from the ensemble-averaged, frequency-domain version of the generalized Burgers equation. The factor quantifies the nonlinear change in the sound pressure level spectrum over distance [B. O. Reichman et al., J. Acoust. Soc. Am. 139, 2505-2513 (2016)]. Here, noise waveforms from a high-performance military jet aircraft are characterized with this gain factor and compared to propagation losses from geometric spreading and atmospheric absorption. Far-field results show that the high-frequency nonlinear gains at high frequencies tend to balance the absorption losses, thus establishing the characteristic spectral slope present in shock-containing noise. Differences as a function of angle, distance, and engine condition are explored.
{"title":"Frequency-domain nonlinearity analysis of noise from a high-performance jet aircraft","authors":"K. Gee, Kyle G. Miller, Brent O. Reichman, Alan T. Wall","doi":"10.1121/2.0000899","DOIUrl":"https://doi.org/10.1121/2.0000899","url":null,"abstract":"Characterization of far-field jet noise spectral evolution can be performed locally with a single microphone measurement using a gain factor that stems from the ensemble-averaged, frequency-domain version of the generalized Burgers equation. The factor quantifies the nonlinear change in the sound pressure level spectrum over distance [B. O. Reichman et al., J. Acoust. Soc. Am. 139, 2505-2513 (2016)]. Here, noise waveforms from a high-performance military jet aircraft are characterized with this gain factor and compared to propagation losses from geometric spreading and atmospheric absorption. Far-field results show that the high-frequency nonlinear gains at high frequencies tend to balance the absorption losses, thus establishing the characteristic spectral slope present in shock-containing noise. Differences as a function of angle, distance, and engine condition are explored.Characterization of far-field jet noise spectral evolution can be performed locally with a single microphone measurement using a gain factor that stems from the ensemble-averaged, frequency-domain version of the generalized Burgers equation. The factor quantifies the nonlinear change in the sound pressure level spectrum over distance [B. O. Reichman et al., J. Acoust. Soc. Am. 139, 2505-2513 (2016)]. Here, noise waveforms from a high-performance military jet aircraft are characterized with this gain factor and compared to propagation losses from geometric spreading and atmospheric absorption. Far-field results show that the high-frequency nonlinear gains at high frequencies tend to balance the absorption losses, thus establishing the characteristic spectral slope present in shock-containing noise. Differences as a function of angle, distance, and engine condition are explored.","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":"85 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90836647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rayleigh streaming in a homogeneous fluid has been extensively studied, and plays an important role in the manipulation of particles in microscale acoustofluidics. In this work, the acoustic streaming is investigated in a glass-silicon microchannel as it evolves in fluids made inhomogeneous in density and compressibility (or speed of sound) by the addition of solute molecules. It is found that the streaming is greatly suppressed in the bulk, due to the competition between the boundary-induced streaming stress and the inhomogeneity-induced acoustic body force. The streaming rolls are initially confined to a narrow region close to the walls, then expand from the walls into the bulk as the inhomogeneity is smeared out by diffusion and advection, and finally the homogeneous state is reached. The efficient suppression of streaming enables manipulation of submicron particles using acoustophoresis. (Less)
{"title":"Suppression of acoustic streaming by the inhomogeneity-induced acoustic body force","authors":"W. Qiu, Jonas Karlsen, H. Bruus, P. Augustsson","doi":"10.1121/2.0000885","DOIUrl":"https://doi.org/10.1121/2.0000885","url":null,"abstract":"Rayleigh streaming in a homogeneous fluid has been extensively studied, and plays an important role in the manipulation of particles in microscale acoustofluidics. In this work, the acoustic streaming is investigated in a glass-silicon microchannel as it evolves in fluids made inhomogeneous in density and compressibility (or speed of sound) by the addition of solute molecules. It is found that the streaming is greatly suppressed in the bulk, due to the competition between the boundary-induced streaming stress and the inhomogeneity-induced acoustic body force. The streaming rolls are initially confined to a narrow region close to the walls, then expand from the walls into the bulk as the inhomogeneity is smeared out by diffusion and advection, and finally the homogeneous state is reached. The efficient suppression of streaming enables manipulation of submicron particles using acoustophoresis. (Less)","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87795979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
When a sound in a vapor is reflected at an interface between the vapor and its condensed phase, the reflected wave is affected by a reflection-induced phase change at the interface, for which the macroscopic continuum theory cannot be applied and the boundary-value problem of the Boltzmann equation should be solved. We numerically solve the Boltzmann-Krook-Welander equation with a finite-difference method, and clarify the characteristics of the reflected wave and the reflection-indeced phase change.When a sound in a vapor is reflected at an interface between the vapor and its condensed phase, the reflected wave is affected by a reflection-induced phase change at the interface, for which the macroscopic continuum theory cannot be applied and the boundary-value problem of the Boltzmann equation should be solved. We numerically solve the Boltzmann-Krook-Welander equation with a finite-difference method, and clarify the characteristics of the reflected wave and the reflection-indeced phase change.
{"title":"Reflection of simple wave at vapor-liquid interface accompanied with phase change","authors":"T. Yano","doi":"10.1121/2.0000887","DOIUrl":"https://doi.org/10.1121/2.0000887","url":null,"abstract":"When a sound in a vapor is reflected at an interface between the vapor and its condensed phase, the reflected wave is affected by a reflection-induced phase change at the interface, for which the macroscopic continuum theory cannot be applied and the boundary-value problem of the Boltzmann equation should be solved. We numerically solve the Boltzmann-Krook-Welander equation with a finite-difference method, and clarify the characteristics of the reflected wave and the reflection-indeced phase change.When a sound in a vapor is reflected at an interface between the vapor and its condensed phase, the reflected wave is affected by a reflection-induced phase change at the interface, for which the macroscopic continuum theory cannot be applied and the boundary-value problem of the Boltzmann equation should be solved. We numerically solve the Boltzmann-Krook-Welander equation with a finite-difference method, and clarify the characteristics of the reflected wave and the reflection-indeced phase change.","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85319276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Various experimental challenges exist in measuring the spatial and temporal field of a nonlinear acoustic pulse propagating through an array of scatterers. Probe interference and undesirable high-frequency response plague typical approaches with acoustic microphones, which are also limited to resolving the pressure field at a single position. Measurements made with optical methods do not have such drawbacks, and schlieren measurements are particularly well suited to measuring both the spatial and temporal evolution of nonlinear pulse propagation in an array of scatterers. Herein, a measurement system is described based on a z-type schlieren setup, which is suitable for measuring axisymmetric phenomena and visualizing weak shock propagation. In order to reduce directivity and initiate nearly spherically-symmetric propagation, laser induced breakdown serves as the source for the nonlinear pulse. A key component of the schlieren system is a standard schliere, which allows quantitative schlieren measurements to be performed. Sizing of the standard schliere is aided by generating estimates of the expected light refraction from the nonlinear pulse, by way of the forward Abel transform. Finally, considerations for experimental sequencing, image capture, and a reconfigurable rod array designed to minimize spurious wave interactions are specified. 15.
{"title":"A measurement system for the study of nonlinear propagation through arrays of scatterers","authors":"Carl R. Hart, G. Lyons","doi":"10.1121/2.0000889","DOIUrl":"https://doi.org/10.1121/2.0000889","url":null,"abstract":"Various experimental challenges exist in measuring the spatial and temporal field of a nonlinear acoustic pulse propagating through an array of scatterers. Probe interference and undesirable high-frequency response plague typical approaches with acoustic microphones, which are also limited to resolving the pressure field at a single position. Measurements made with optical methods do not have such drawbacks, and schlieren measurements are particularly well suited to measuring both the spatial and temporal evolution of nonlinear pulse propagation in an array of scatterers. Herein, a measurement system is described based on a z-type schlieren setup, which is suitable for measuring axisymmetric phenomena and visualizing weak shock propagation. In order to reduce directivity and initiate nearly spherically-symmetric propagation, laser induced breakdown serves as the source for the nonlinear pulse. A key component of the schlieren system is a standard schliere, which allows quantitative schlieren measurements to be performed. Sizing of the standard schliere is aided by generating estimates of the expected light refraction from the nonlinear pulse, by way of the forward Abel transform. Finally, considerations for experimental sequencing, image capture, and a reconfigurable rod array designed to minimize spurious wave interactions are specified. 15.","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84333805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The food industry has studied turbulent streaming from an ultrasonic horn reactor, where the turbulent flow field can be modelled by a laminar jet flow that has a turbulent eddy viscosity [M. J. Lighthill, “Acoustic streaming,” J. Sound Vib. 61 (3), (1978) 391–418]. Work by Kumar (2006), Trujillo (2009) and others successfully compared the results with CFD models, have sparked interest in revisiting turbulent streaming by an ultrasonic horn, resulting in this presentation. Our demonstration studies the turbulent flow generated by the interaction between two mutually perpendicular crossed streaming jets – which both exhibit turbulent behavior. We are specifically interested in the flow field in the forward and backward directions defined by the bisecting line segment ±45 degrees from the axis of each streaming jet, with the line segment located in the plane shared by the jet axes. The apparatus consists of two Langevin ultrasonic transducers (125 kHz) that are both equipped with a half-wavelength exponential horn. The horns are slightly submerged in an open acrylic water tank to allow for viewing of the flow field. A particle image velocimeter (PIV) will be used to measure the turbulent flow velocity field in the plane of the interaction region aforementioned.The food industry has studied turbulent streaming from an ultrasonic horn reactor, where the turbulent flow field can be modelled by a laminar jet flow that has a turbulent eddy viscosity [M. J. Lighthill, “Acoustic streaming,” J. Sound Vib. 61 (3), (1978) 391–418]. Work by Kumar (2006), Trujillo (2009) and others successfully compared the results with CFD models, have sparked interest in revisiting turbulent streaming by an ultrasonic horn, resulting in this presentation. Our demonstration studies the turbulent flow generated by the interaction between two mutually perpendicular crossed streaming jets – which both exhibit turbulent behavior. We are specifically interested in the flow field in the forward and backward directions defined by the bisecting line segment ±45 degrees from the axis of each streaming jet, with the line segment located in the plane shared by the jet axes. The apparatus consists of two Langevin ultrasonic transducers (125 kHz) that are both equipped with a half-wavelength exponenti...
{"title":"Turbulent flow due to the interaction of two mutually perpendicular crossed turbulent streaming jets in water","authors":"Jenna Cartron, M. Korman","doi":"10.1121/2.0000884","DOIUrl":"https://doi.org/10.1121/2.0000884","url":null,"abstract":"The food industry has studied turbulent streaming from an ultrasonic horn reactor, where the turbulent flow field can be modelled by a laminar jet flow that has a turbulent eddy viscosity [M. J. Lighthill, “Acoustic streaming,” J. Sound Vib. 61 (3), (1978) 391–418]. Work by Kumar (2006), Trujillo (2009) and others successfully compared the results with CFD models, have sparked interest in revisiting turbulent streaming by an ultrasonic horn, resulting in this presentation. Our demonstration studies the turbulent flow generated by the interaction between two mutually perpendicular crossed streaming jets – which both exhibit turbulent behavior. We are specifically interested in the flow field in the forward and backward directions defined by the bisecting line segment ±45 degrees from the axis of each streaming jet, with the line segment located in the plane shared by the jet axes. The apparatus consists of two Langevin ultrasonic transducers (125 kHz) that are both equipped with a half-wavelength exponential horn. The horns are slightly submerged in an open acrylic water tank to allow for viewing of the flow field. A particle image velocimeter (PIV) will be used to measure the turbulent flow velocity field in the plane of the interaction region aforementioned.The food industry has studied turbulent streaming from an ultrasonic horn reactor, where the turbulent flow field can be modelled by a laminar jet flow that has a turbulent eddy viscosity [M. J. Lighthill, “Acoustic streaming,” J. Sound Vib. 61 (3), (1978) 391–418]. Work by Kumar (2006), Trujillo (2009) and others successfully compared the results with CFD models, have sparked interest in revisiting turbulent streaming by an ultrasonic horn, resulting in this presentation. Our demonstration studies the turbulent flow generated by the interaction between two mutually perpendicular crossed streaming jets – which both exhibit turbulent behavior. We are specifically interested in the flow field in the forward and backward directions defined by the bisecting line segment ±45 degrees from the axis of each streaming jet, with the line segment located in the plane shared by the jet axes. The apparatus consists of two Langevin ultrasonic transducers (125 kHz) that are both equipped with a half-wavelength exponenti...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73180202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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