Pub Date : 2025-07-29DOI: 10.1016/j.wavemoti.2025.103612
Muhammad Shoaib , Zhijing Wu , Jiping Jing , Fengming Li , Long Liu
In this paper, the transverse and longitudinal wave motions of a fluid-conveying deployable meta-pipe incorporating periodic inertial amplification (IA) mechanisms are systematically investigated. The proposed structure aims to enhance vibration attenuation based on the band gap (BG) property in low-frequency ranges. The dynamic model of the IA mechanism is established to precisely characterize the inertial forces generated by the coupled axial-bending deformation in the base pipe structure. Based on the Bloch theorem, the dispersion curves are analyzed using the transfer matrix method (TMM). An experiment prototype is manufactured and subjected to vibration testing for validation of the theoretical model. Parametric analysis reveals that both the position and bandwidth of transverse and longitudinal BGs exhibit significant dependence on variations in: (1) fluid velocity, (2) deploying velocity, (3) IA mechanism’s parameters (mass and angle) and (4) the length of the unit cell. This research can establish both theoretical and experimental foundations for engineering design focused on enhanced vibration attenuation in conveying-fluid pipes.
{"title":"Band-gap properties of fluid-conveying deployable meta-pipes with periodic inertial amplification mechanisms","authors":"Muhammad Shoaib , Zhijing Wu , Jiping Jing , Fengming Li , Long Liu","doi":"10.1016/j.wavemoti.2025.103612","DOIUrl":"10.1016/j.wavemoti.2025.103612","url":null,"abstract":"<div><div>In this paper, the transverse and longitudinal wave motions of a fluid-conveying deployable meta-pipe incorporating periodic inertial amplification (IA) mechanisms are systematically investigated. The proposed structure aims to enhance vibration attenuation based on the band gap (BG) property in low-frequency ranges. The dynamic model of the IA mechanism is established to precisely characterize the inertial forces generated by the coupled axial-bending deformation in the base pipe structure. Based on the Bloch theorem, the dispersion curves are analyzed using the transfer matrix method (TMM). An experiment prototype is manufactured and subjected to vibration testing for validation of the theoretical model. Parametric analysis reveals that both the position and bandwidth of transverse and longitudinal BGs exhibit significant dependence on variations in: (1) fluid velocity, (2) deploying velocity, (3) IA mechanism’s parameters (mass and angle) and (4) the length of the unit cell. This research can establish both theoretical and experimental foundations for engineering design focused on enhanced vibration attenuation in conveying-fluid pipes.</div></div>","PeriodicalId":49367,"journal":{"name":"Wave Motion","volume":"139 ","pages":"Article 103612"},"PeriodicalIF":2.5,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144757329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-23DOI: 10.1016/j.wavemoti.2025.103608
Xuemin Yao , Jinjie Wen , Yuanhang Li , Junfei Zhao
In this paper, we present mechanistic investigations on certain bounded/unbounded breather molecules and transformed molecular wave formations through systematic analysis for an extended (3+1)-dimensional Jimbo–Miwa equation in fluid dynamics. Through characteristic lines analysis, we establish transformed wave solutions bifurcating from breather modes under critical state transition conditions. Such solutions demonstrate temporally evolving characteristics manifested as dynamic amplitude modulations and parametric waveform deformations. Moreover, we systematically investigate breather or transformed molecular wave complexes as collisionless structures, where the fundamental constituents are identified as individual breather waves and novel transformed wave counterparts. Unbounded or bounded molecular wave complexes, comprising identical or distinct constituent components, maintain fixed phase-locked separation distances while demonstrating propagation stability governed by nonlinear coupling constraints. These findings establish a potential theoretical framework for experimental studies in fluid dynamics, while also offering novel perspectives on the behavior of molecular waves in broader nonlinear physical systems.
{"title":"Mechanism investigations on certain unbounded/bounded breather molecules and transformed molecular waves for an extended (3+1)-dimensional Jimbo–Miwa equation in fluid mechanics","authors":"Xuemin Yao , Jinjie Wen , Yuanhang Li , Junfei Zhao","doi":"10.1016/j.wavemoti.2025.103608","DOIUrl":"10.1016/j.wavemoti.2025.103608","url":null,"abstract":"<div><div>In this paper, we present mechanistic investigations on certain bounded/unbounded breather molecules and transformed molecular wave formations through systematic analysis for an extended (3+1)-dimensional Jimbo–Miwa equation in fluid dynamics. Through characteristic lines analysis, we establish transformed wave solutions bifurcating from breather modes under critical state transition conditions. Such solutions demonstrate temporally evolving characteristics manifested as dynamic amplitude modulations and parametric waveform deformations. Moreover, we systematically investigate breather or transformed molecular wave complexes as collisionless structures, where the fundamental constituents are identified as individual breather waves and novel transformed wave counterparts. Unbounded or bounded molecular wave complexes, comprising identical or distinct constituent components, maintain fixed phase-locked separation distances while demonstrating propagation stability governed by nonlinear coupling constraints. These findings establish a potential theoretical framework for experimental studies in fluid dynamics, while also offering novel perspectives on the behavior of molecular waves in broader nonlinear physical systems.</div></div>","PeriodicalId":49367,"journal":{"name":"Wave Motion","volume":"139 ","pages":"Article 103608"},"PeriodicalIF":2.1,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-21DOI: 10.1016/j.wavemoti.2025.103607
Neetu Malik , Komal Gajroiya , Jitander Singh Sikka
This study aims to examine how the propagation of Shear Horizontal wave (SH-type waves) in a magneto-elastic fiber-reinforced (MEFR) layer with finite thickness is affected by initial stress. It rests upon a poroelastic transversely isotropic inhomogeneous half-space. The upper boundary of the layer is assumed to be rigid, and the layer and half-space are welded together. The displacement components of both the layer and half-space were derived and subsequently analyzed. The dispersion relation governing the propagation of SH-type waves was obtained and examined by applying appropriate boundary conditions for various scenarios. The confirmation of the mathematical model’s validity is evidenced by the simplification of the dispersion relation, which in turn streamlines the existing velocity wave equation for SH waves. The numerical computations were performed for distinct materials (steel and crystalline graphite) of the considered upper MEFR layer using the MATHEMATICA software, and the results were graphically presented. The dispersion curves provide insights into the impact of various parameters, including initial stress, magneto-elastic coupling, reinforcement, wave angle with respect to the magnetic field, heterogeneity of the half-space, porosity, and dynamic tortuosity, on wave propagation. Understanding the behavior of seismic waves can have significant practical implications for earthquake engineering and geophysics. Therefore, the findings of this study contribute to enhancing our knowledge of wave propagation, offering valuable insights for relevant fields.
{"title":"Effect of horizontal and vertical components of initial stress on SH-wave propagation in a magneto-elastic fiber-reinforced (MEFR) layer","authors":"Neetu Malik , Komal Gajroiya , Jitander Singh Sikka","doi":"10.1016/j.wavemoti.2025.103607","DOIUrl":"10.1016/j.wavemoti.2025.103607","url":null,"abstract":"<div><div>This study aims to examine how the propagation of Shear Horizontal wave (SH-type waves) in a magneto-elastic fiber-reinforced (MEFR) layer with finite thickness is affected by initial stress. It rests upon a poroelastic transversely isotropic inhomogeneous half-space. The upper boundary of the layer is assumed to be rigid, and the layer and half-space are welded together. The displacement components of both the layer and half-space were derived and subsequently analyzed. The dispersion relation governing the propagation of SH-type waves was obtained and examined by applying appropriate boundary conditions for various scenarios. The confirmation of the mathematical model’s validity is evidenced by the simplification of the dispersion relation, which in turn streamlines the existing velocity wave equation for SH waves. The numerical computations were performed for distinct materials (steel and crystalline graphite) of the considered upper MEFR layer using the MATHEMATICA software, and the results were graphically presented. The dispersion curves provide insights into the impact of various parameters, including initial stress, magneto-elastic coupling, reinforcement, wave angle with respect to the magnetic field, heterogeneity of the half-space, porosity, and dynamic tortuosity, on wave propagation. Understanding the behavior of seismic waves can have significant practical implications for earthquake engineering and geophysics. Therefore, the findings of this study contribute to enhancing our knowledge of wave propagation, offering valuable insights for relevant fields.</div></div>","PeriodicalId":49367,"journal":{"name":"Wave Motion","volume":"139 ","pages":"Article 103607"},"PeriodicalIF":2.1,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144702738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-19DOI: 10.1016/j.wavemoti.2025.103605
Halis Yilmaz
We employ a modified Darboux transformation to derive quasideterminant solutions for the modified Wadati–Konno–Ichikawa (mWKI) equation, an equivalent form of the WKI equation. As particular examples, we present multi-soliton solutions for both the focusing and defocusing cases using a zero seed solution. Additionally, we derive breather and rogue wave solutions of the mWKI equation starting from a non-zero seed solution.
{"title":"Quasideterminant solutions for the Wadati–Konno–Ichikawa equation","authors":"Halis Yilmaz","doi":"10.1016/j.wavemoti.2025.103605","DOIUrl":"10.1016/j.wavemoti.2025.103605","url":null,"abstract":"<div><div>We employ a modified Darboux transformation to derive quasideterminant solutions for the modified Wadati–Konno–Ichikawa (mWKI) equation, an equivalent form of the WKI equation. As particular examples, we present multi-soliton solutions for both the focusing and defocusing cases using a zero seed solution. Additionally, we derive breather and rogue wave solutions of the mWKI equation starting from a non-zero seed solution.</div></div>","PeriodicalId":49367,"journal":{"name":"Wave Motion","volume":"139 ","pages":"Article 103605"},"PeriodicalIF":2.1,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144685453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-19DOI: 10.1016/j.wavemoti.2025.103606
Elie Salemeh, Simon Félix, Vincent Pagneux
In wave transport through complex media, the single-channel regime is characterized by the loss of sensitivity to incidence conditions, resulting in an invariant pattern of the transmitted wave. So far, such “frozen” patterns have been observed in localized disordered media and in periodic waveguides. In this paper, we show that the same mechanism can occur in the transmission through gratings when properly designed, allowing the observation of the freezing when an incident plane wave is scattered by a grating composed of two successive arrays of scatterers: one mixing the incident orders in arbitrary ways, followed by a freezing array periodically structured in the longitudinal direction, normal to the grating plane. Unlike localized disordered media, where freezing occurs only with evanescent waves, gratings, similarly to periodic waveguides, can exhibit freezing with propagating waves when a single Bloch mode is propagating in the longitudinal direction. Moreover, we show different classes of grating geometries for which the occurrence of freezing is sensitive or insensitive to the incidence angle.
{"title":"Freezing of the transmitted wave pattern through gratings","authors":"Elie Salemeh, Simon Félix, Vincent Pagneux","doi":"10.1016/j.wavemoti.2025.103606","DOIUrl":"10.1016/j.wavemoti.2025.103606","url":null,"abstract":"<div><div>In wave transport through complex media, the single-channel regime is characterized by the loss of sensitivity to incidence conditions, resulting in an invariant pattern of the transmitted wave. So far, such “frozen” patterns have been observed in localized disordered media and in periodic waveguides. In this paper, we show that the same mechanism can occur in the transmission through gratings when properly designed, allowing the observation of the freezing when an incident plane wave is scattered by a grating composed of two successive arrays of scatterers: one mixing the incident orders in arbitrary ways, followed by a freezing array periodically structured in the longitudinal direction, normal to the grating plane. Unlike localized disordered media, where freezing occurs only with evanescent waves, gratings, similarly to periodic waveguides, can exhibit freezing with propagating waves when a single Bloch mode is propagating in the longitudinal direction. Moreover, we show different classes of grating geometries for which the occurrence of freezing is sensitive or insensitive to the incidence angle.</div></div>","PeriodicalId":49367,"journal":{"name":"Wave Motion","volume":"139 ","pages":"Article 103606"},"PeriodicalIF":2.1,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144714095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-19DOI: 10.1016/j.wavemoti.2025.103604
Yi-Lin Tian , Wen-Yuan Li , Nong-Sen Li , Rui-Gang Zhang , Ji-Feng Cui
In the text, we deliberate the (3+1)-dimensional variable-coefficient potential Yu-Toda-Sasa-Fukuyama equation (YTST) in an elastic (or in a two-layer-liquid) medium, and its bilinear form is derived by Bell polynomials. Via symbolic computation method and Hirota bilinear form, the first-order, second-order and third-order rogue wave solutions are presented, involving lump-type, lump-kink-type, periodic and line rogue waves. The effect of variable coefficient functions and parameter values of the center on the shapes and peak numbers of rogue waves is demonstrated and explained in terms of three-dimensional graphs and contours. The appearances bearing fission and propagation in the periodic background are duly traced. The novel outcomes fill the gap in rogue wave solutions for this model, which furnish great awareness going deeply into variable coefficient equations.
{"title":"Dynamics of multiple rogue waves for (3+1)-dimensional variable-coefficient potential Yu-Toda-Sasa-Fukuyama equation","authors":"Yi-Lin Tian , Wen-Yuan Li , Nong-Sen Li , Rui-Gang Zhang , Ji-Feng Cui","doi":"10.1016/j.wavemoti.2025.103604","DOIUrl":"10.1016/j.wavemoti.2025.103604","url":null,"abstract":"<div><div>In the text, we deliberate the (3+1)-dimensional variable-coefficient potential Yu-Toda-Sasa-Fukuyama equation (YTST) in an elastic (or in a two-layer-liquid) medium, and its bilinear form is derived by Bell polynomials. Via symbolic computation method and Hirota bilinear form, the first-order, second-order and third-order rogue wave solutions are presented, involving lump-type, lump-kink-type, periodic and line rogue waves. The effect of variable coefficient functions and parameter values of the center on the shapes and peak numbers of rogue waves is demonstrated and explained in terms of three-dimensional graphs and contours. The appearances bearing fission and propagation in the periodic background are duly traced. The novel outcomes fill the gap in rogue wave solutions for this model, which furnish great awareness going deeply into variable coefficient equations.</div></div>","PeriodicalId":49367,"journal":{"name":"Wave Motion","volume":"139 ","pages":"Article 103604"},"PeriodicalIF":2.1,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-14DOI: 10.1016/j.wavemoti.2025.103609
Lijuan Chu , Li Li , Yang Liu
The complexity and diversity of Earth materials pose significant challenges to seismic detection techniques, especially in oil and gas exploration. The development and application of the viscoelastic theory and microscopic flow theory of porous fluids have made the analysis of elastic wave propagation information one of the main methods of detection. This study investigates the propagation characteristics of elastic waves in a sandwich structure, which comprises of layers of elastic, porous viscoelastic and viscoelastic solids, placed on top of each other. The fractional order Zener model, Biot-squirt flow (BISQ) model, and non-Newtonian fluid theory are employed to describe the viscoelasticity of the solid frame, microscopic flow of porous fluids, and viscosity of porous fluids, respectively. To our knowledge, existing studies on unwelded bonded boundary conditions have not yet incorporated the BISQ model and fractional derivative theory. We aim to address this critical knowledge gap. Both welded and loose boundary conditions have been taken into account in our model. Graphical representations illustrate the numerical simulation findings. Our study suggests that the viscoelasticity of solid frame, the flow characteristics of porous fluids, welded and loose boundary condition have significant impact on the propagation properties of elastic waves. Hence, the study of the above factors in Earth materials will appropriately describe the subsequent dissipation of seismic wave energy and the analysis of stratigraphic structures and soil properties.
{"title":"Comprehensive modeling of elastic wave propagation in porous viscoelastic media incorporating fractional-order derivative under welded and loose boundary conditions","authors":"Lijuan Chu , Li Li , Yang Liu","doi":"10.1016/j.wavemoti.2025.103609","DOIUrl":"10.1016/j.wavemoti.2025.103609","url":null,"abstract":"<div><div>The complexity and diversity of Earth materials pose significant challenges to seismic detection techniques, especially in oil and gas exploration. The development and application of the viscoelastic theory and microscopic flow theory of porous fluids have made the analysis of elastic wave propagation information one of the main methods of detection. This study investigates the propagation characteristics of elastic waves in a sandwich structure, which comprises of layers of elastic, porous viscoelastic and viscoelastic solids, placed on top of each other. The fractional order Zener model, Biot-squirt flow (BISQ) model, and non-Newtonian fluid theory are employed to describe the viscoelasticity of the solid frame, microscopic flow of porous fluids, and viscosity of porous fluids, respectively. To our knowledge, existing studies on unwelded bonded boundary conditions have not yet incorporated the BISQ model and fractional derivative theory. We aim to address this critical knowledge gap. Both welded and loose boundary conditions have been taken into account in our model. Graphical representations illustrate the numerical simulation findings. Our study suggests that the viscoelasticity of solid frame, the flow characteristics of porous fluids, welded and loose boundary condition have significant impact on the propagation properties of elastic waves. Hence, the study of the above factors in Earth materials will appropriately describe the subsequent dissipation of seismic wave energy and the analysis of stratigraphic structures and soil properties.</div></div>","PeriodicalId":49367,"journal":{"name":"Wave Motion","volume":"139 ","pages":"Article 103609"},"PeriodicalIF":2.1,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144654791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-11DOI: 10.1016/j.wavemoti.2025.103603
Philip Rosenau , Alexander Oron
We introduce and study a class of equations that merge the Gardner’s-type, non-convex, advection with regularized long-wave dispersion, also known as Benjamin–Bona–Mahony equation, to the effect that unlike the unidirectional Gardner solitons, the presented model supports bidirectional propagation of at least three types of solitary waves and begets a whole gallery of chase and collision interactions. Among the novel features of our model, we mention the possibility that one of the solitons reverses its direction upon interaction with another soliton. Extension of the model to higher dimensions typically causes the newly found solitary waves to split into a countable sequence of multi-modal solitary waves wherein either mode’s amplitude increases with its modality, or the modes condense near their potential’s top.
{"title":"Novel solitary patterns in a class of regularized Gardner equations","authors":"Philip Rosenau , Alexander Oron","doi":"10.1016/j.wavemoti.2025.103603","DOIUrl":"10.1016/j.wavemoti.2025.103603","url":null,"abstract":"<div><div>We introduce and study a class of equations that merge the Gardner’s-type, non-convex, advection with regularized long-wave dispersion, also known as Benjamin–Bona–Mahony equation, to the effect that unlike the unidirectional Gardner solitons, the presented model supports bidirectional propagation of at least three types of solitary waves and begets a whole gallery of chase and collision interactions. Among the novel features of our model, we mention the possibility that one of the solitons <em>reverses its direction</em> upon interaction with another soliton. Extension of the model to higher dimensions typically causes the newly found solitary waves to split into <em>a countable sequence of multi-modal solitary waves</em> wherein either mode’s amplitude increases with its modality, or the modes condense near their potential’s top.</div></div>","PeriodicalId":49367,"journal":{"name":"Wave Motion","volume":"139 ","pages":"Article 103603"},"PeriodicalIF":2.1,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144632660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-07DOI: 10.1016/j.wavemoti.2025.103602
Yakov Itin
The explanation of the basic acoustic properties of crystals requires a recognition of the acoustic axes. To derive the acoustic axes in a given material, one requires both a workable method and the necessary and sufficient criteria for the existence of the acoustic axes in a partial propagation direction. This paper’s primary input is an alternate minimal polynomial-based system of acoustic axes conditions. In this approach, we derive a novel additional characteristic of acoustic axes: the directions in which the minimal polynomial of the third order is reduced to that of the second order. Next, we offer a general solution, that utilizes a scalar and a unit vector for defining the acoustic tensor along the acoustic axis. It is shown that the scalar matches the eigenvalue of the reduced acoustic tensor, and the vector corresponds to the polarization into the single eigenvalue direction. We use the minimal polynomial construction to demonstrate the equivalence of different acoustic axis criteria. We demonstrate the applicability of this approach to actual computations of the acoustic axes and their fundamental properties (phase speeds and polarizations) for high symmetry cases, such as isotropic materials and RTHC crystals.
{"title":"Acoustic axes conditions revised","authors":"Yakov Itin","doi":"10.1016/j.wavemoti.2025.103602","DOIUrl":"10.1016/j.wavemoti.2025.103602","url":null,"abstract":"<div><div>The explanation of the basic acoustic properties of crystals requires a recognition of the acoustic axes. To derive the acoustic axes in a given material, one requires both a workable method and the necessary and sufficient criteria for the existence of the acoustic axes in a partial propagation direction. This paper’s primary input is an alternate minimal polynomial-based system of acoustic axes conditions. In this approach, we derive a novel additional characteristic of acoustic axes: the directions in which the minimal polynomial of the third order is reduced to that of the second order. Next, we offer a general solution, that utilizes a scalar and a unit vector for defining the acoustic tensor along the acoustic axis. It is shown that the scalar matches the eigenvalue of the reduced acoustic tensor, and the vector corresponds to the polarization into the single eigenvalue direction. We use the minimal polynomial construction to demonstrate the equivalence of different acoustic axis criteria. We demonstrate the applicability of this approach to actual computations of the acoustic axes and their fundamental properties (phase speeds and polarizations) for high symmetry cases, such as isotropic materials and RTHC crystals.</div></div>","PeriodicalId":49367,"journal":{"name":"Wave Motion","volume":"139 ","pages":"Article 103602"},"PeriodicalIF":2.1,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-03DOI: 10.1016/j.wavemoti.2025.103600
Maria M. Vuin, Dmitri Kartofelev, Andrus Salupere, Päivo Simson
In this paper acoustic wave propagation through nonlinear porous felt-like material is studied numerically. A 1D model equation based on the experimentally obtained constitutive relation is used. A dispersion and dissipation analysis are performed. The possible effects of band gap (BG) and negative group velocity (NGV) on the wave propagation are investigated. For this reason, the propagation of pulses with characteristic widths corresponding to wavenumbers that are located in and near the BG and the region with NGV are studied. It is claimed that if the material loading and unloading timescale is much too great in comparison to the felt relaxation time, then any possible contribution of BG and NGV on the wave shape evolution is negligibly small. Paper concludes that felts are not metamaterials with noteworthy properties. Possible reasons for these conclusions are given. It is obvious that the proper understanding of NGV phenomenon will lead to significant breakthroughs in unwoven fibrous felt-type material engineering and applications. These applications may include vibration and noise control and even wave manipulation.
{"title":"Numerical investigation into acoustic wave propagation in felt-type material with band gap and negative group velocity","authors":"Maria M. Vuin, Dmitri Kartofelev, Andrus Salupere, Päivo Simson","doi":"10.1016/j.wavemoti.2025.103600","DOIUrl":"10.1016/j.wavemoti.2025.103600","url":null,"abstract":"<div><div>In this paper acoustic wave propagation through nonlinear porous felt-like material is studied numerically. A 1D model equation based on the experimentally obtained constitutive relation is used. A dispersion and dissipation analysis are performed. The possible effects of band gap (BG) and negative group velocity (NGV) on the wave propagation are investigated. For this reason, the propagation of pulses with characteristic widths corresponding to wavenumbers that are located in and near the BG and the region with NGV are studied. It is claimed that if the material loading and unloading timescale is much too great in comparison to the felt relaxation time, then any possible contribution of BG and NGV on the wave shape evolution is negligibly small. Paper concludes that felts are not metamaterials with noteworthy properties. Possible reasons for these conclusions are given. It is obvious that the proper understanding of NGV phenomenon will lead to significant breakthroughs in unwoven fibrous felt-type material engineering and applications. These applications may include vibration and noise control and even wave manipulation.</div></div>","PeriodicalId":49367,"journal":{"name":"Wave Motion","volume":"139 ","pages":"Article 103600"},"PeriodicalIF":2.1,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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