Pub Date : 2023-11-02DOI: 10.1080/17455030.2022.2118895
Yahya Baykal, Yalçın Ata, Muhsin C. Gökçe
AbstractTip and tilt corrections are applied to the bit error rate of an M-ary pulse position-modulated optical wireless communication system operating in a turbulent marine atmosphere. For the collimated Gaussian laser beam, using the average received power and power scintillation index at the receiver, the reduction in bit error rate is evaluated. Reduction in bit error rate is defined by the metric of bit error rate with tip and tilt correction normalized by the bit error rate without tip and tilt correction. Reduction in bit error rate is found against the changes in average current gain of the avalanche photodiode, data bit rate, and the M value for various structure constant, link length, and wavelength values. Our results show that the application of tip and tilt corrections effectively reduces the bit error rate of the M-ary pulse position-modulated optical wireless communication system in a turbulent marine atmosphere.KEYWORDS: Optical wireless communication systemmarine atmospheric turbulencepulse position modulationbit error rate Disclosure statementNo potential conflict of interest was reported by the author(s).
{"title":"Tip and tilt-corrected bit error rate improvement of <i>M</i> -ary pulse position-modulated optical wireless communication in the marine atmosphere","authors":"Yahya Baykal, Yalçın Ata, Muhsin C. Gökçe","doi":"10.1080/17455030.2022.2118895","DOIUrl":"https://doi.org/10.1080/17455030.2022.2118895","url":null,"abstract":"AbstractTip and tilt corrections are applied to the bit error rate of an M-ary pulse position-modulated optical wireless communication system operating in a turbulent marine atmosphere. For the collimated Gaussian laser beam, using the average received power and power scintillation index at the receiver, the reduction in bit error rate is evaluated. Reduction in bit error rate is defined by the metric of bit error rate with tip and tilt correction normalized by the bit error rate without tip and tilt correction. Reduction in bit error rate is found against the changes in average current gain of the avalanche photodiode, data bit rate, and the M value for various structure constant, link length, and wavelength values. Our results show that the application of tip and tilt corrections effectively reduces the bit error rate of the M-ary pulse position-modulated optical wireless communication system in a turbulent marine atmosphere.KEYWORDS: Optical wireless communication systemmarine atmospheric turbulencepulse position modulationbit error rate Disclosure statementNo potential conflict of interest was reported by the author(s).","PeriodicalId":23598,"journal":{"name":"Waves in Random and Complex Media","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135975737","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 : 2023-11-02DOI: 10.1080/17455030.2022.2072530
None Zeeshan, Haroon Ur Rasheed, Muhammad Naeem, None Ataullah
AbstractThe polyethene coating is frequently functionalized to cables or pipes for corrosion prevention, voltage differential, mechanical characteristics, and environmental legislation. The metal coating technique, in particular, is important in a variety of commercial applications. Coaxial extrusion, immersion, and electromagnetic application are examples of wire surface treatments. The wire coating procedure necessitates an increase in thermal performance. As a result, this research aims to determine how floating nanoparticles affect the mass and heat transport mechanisms of non-Newtonian fluid in the posttreatment for cable coating processes. For nanofluids, the Buongiorno model is used, including variable viscosity. The original mathematical formulation in terms of nonlinear ODEs for bvph2 is altered to first-order ODEs using similarity transformation. The data collection for the projected bvph2 is developed for variables related to the proposed model manipulating the velocity consuming the explicit bvph2 technique. The exercise, confirmation, and analysis processes of the ND-solve method are utilized to appraise the attained results of bvhp2 for numerous cases, and an assessment of the achieved consequences is executed with available statistics set to pattern the correctness and efficiency of the suggested algorithm for the scrutiny of non-Newtonian fluid problem connected bvph2. The prevailing uniformity of recommended conclusions with published findings designates the legitimacy of the structure, and the accurateness of 10−6 is also accomplished. The analytical findings of this investigation revealed that within the Reynolds modeling, the stress on the whole wire surface combined with shear forces at the surface predominates Vogel’s model. The contribution of nanomaterials upon force on the entire surface of wire and shear forces at the surface appears positive. A non-Newtonian feature can increase the capping substance’s velocity. This research could aid in the advancement of wire coating technologies. For the first instance, the significance of nanotechnology during wire coating evaluation is explored by utilizing Brownian motion with generation/absorption slip processes. For time-dependent viscosity, two alternative models are useful.KEYWORDS: Bvph2 and ND-solve solutionwire surface coatingpressurized coating dienanomaterialsthird-grade fluidNumerical and Analytical solutions AcknowledgementThe authors would like to thank the Deanship of Scientific Research at Umm Al-Qura University.Disclosure statementNo potential conflict of interest was reported by the author(s).
{"title":"Viscoelastic third-order nanofluid MHD flow for wire coating purpose inside canonical coating die with variable viscosity effect: numerical and analytical solutions","authors":"None Zeeshan, Haroon Ur Rasheed, Muhammad Naeem, None Ataullah","doi":"10.1080/17455030.2022.2072530","DOIUrl":"https://doi.org/10.1080/17455030.2022.2072530","url":null,"abstract":"AbstractThe polyethene coating is frequently functionalized to cables or pipes for corrosion prevention, voltage differential, mechanical characteristics, and environmental legislation. The metal coating technique, in particular, is important in a variety of commercial applications. Coaxial extrusion, immersion, and electromagnetic application are examples of wire surface treatments. The wire coating procedure necessitates an increase in thermal performance. As a result, this research aims to determine how floating nanoparticles affect the mass and heat transport mechanisms of non-Newtonian fluid in the posttreatment for cable coating processes. For nanofluids, the Buongiorno model is used, including variable viscosity. The original mathematical formulation in terms of nonlinear ODEs for bvph2 is altered to first-order ODEs using similarity transformation. The data collection for the projected bvph2 is developed for variables related to the proposed model manipulating the velocity consuming the explicit bvph2 technique. The exercise, confirmation, and analysis processes of the ND-solve method are utilized to appraise the attained results of bvhp2 for numerous cases, and an assessment of the achieved consequences is executed with available statistics set to pattern the correctness and efficiency of the suggested algorithm for the scrutiny of non-Newtonian fluid problem connected bvph2. The prevailing uniformity of recommended conclusions with published findings designates the legitimacy of the structure, and the accurateness of 10−6 is also accomplished. The analytical findings of this investigation revealed that within the Reynolds modeling, the stress on the whole wire surface combined with shear forces at the surface predominates Vogel’s model. The contribution of nanomaterials upon force on the entire surface of wire and shear forces at the surface appears positive. A non-Newtonian feature can increase the capping substance’s velocity. This research could aid in the advancement of wire coating technologies. For the first instance, the significance of nanotechnology during wire coating evaluation is explored by utilizing Brownian motion with generation/absorption slip processes. For time-dependent viscosity, two alternative models are useful.KEYWORDS: Bvph2 and ND-solve solutionwire surface coatingpressurized coating dienanomaterialsthird-grade fluidNumerical and Analytical solutions AcknowledgementThe authors would like to thank the Deanship of Scientific Research at Umm Al-Qura University.Disclosure statementNo potential conflict of interest was reported by the author(s).","PeriodicalId":23598,"journal":{"name":"Waves in Random and Complex Media","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135975925","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 : 2023-11-02DOI: 10.1080/17455030.2022.2096272
Josselin Garnier, Knut Sølna
AbstractA theory for the characterization of the fourth-order moment of electromagnetic wave beams is presented in the case when the source is partially coherent. A Gaussian–Schell model is used for the partially coherent random source. The white-noise paraxial regime is considered, which holds when the wavelength is much smaller than the correlation radius of the source, the beam radius of the source, and the correlation length of the medium, which are themselves much smaller than the propagation distance. The complex wave amplitude field can then be described by the Itô-Schrödinger equation. This equation gives closed evolution equations for the wave field moments at all orders and here the fourth-order moment equations are considered. The general fourth-order moment equations are solved explicitly in the scintillation regime (when the correlation radius of the source is of the same order as the correlation radius of the medium, but the beam radius is much larger) and the result gives a characterization of the intensity covariance function. The form of the intensity covariance function derives from the solution of the transport equation for the Wigner distribution associated with the second-order wave moment. The fourth-order moment results for polarized waves are used in an application for imaging of partially coherent sources.Keywords: Random mediaelectromagnetic wavesmultiple scatteringSchrödinger equationGauss–Schell modelscintillationsource imaging Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingJG was supported by the Agence Nationale pour la Recherche under Grant No. ANR-19-CE46-0007 (project ICCI), and Air Force Office of Scientific Research under grant FA9550-22-1-0176. KS was supported by the Air Force Office of Scientific Research under grant (FA9550-22-1-0176) and the National Science Foundation under grant (DMS-2010046).
{"title":"Fourth-order moments analysis for partially coherent electromagnetic beams in random media","authors":"Josselin Garnier, Knut Sølna","doi":"10.1080/17455030.2022.2096272","DOIUrl":"https://doi.org/10.1080/17455030.2022.2096272","url":null,"abstract":"AbstractA theory for the characterization of the fourth-order moment of electromagnetic wave beams is presented in the case when the source is partially coherent. A Gaussian–Schell model is used for the partially coherent random source. The white-noise paraxial regime is considered, which holds when the wavelength is much smaller than the correlation radius of the source, the beam radius of the source, and the correlation length of the medium, which are themselves much smaller than the propagation distance. The complex wave amplitude field can then be described by the Itô-Schrödinger equation. This equation gives closed evolution equations for the wave field moments at all orders and here the fourth-order moment equations are considered. The general fourth-order moment equations are solved explicitly in the scintillation regime (when the correlation radius of the source is of the same order as the correlation radius of the medium, but the beam radius is much larger) and the result gives a characterization of the intensity covariance function. The form of the intensity covariance function derives from the solution of the transport equation for the Wigner distribution associated with the second-order wave moment. The fourth-order moment results for polarized waves are used in an application for imaging of partially coherent sources.Keywords: Random mediaelectromagnetic wavesmultiple scatteringSchrödinger equationGauss–Schell modelscintillationsource imaging Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingJG was supported by the Agence Nationale pour la Recherche under Grant No. ANR-19-CE46-0007 (project ICCI), and Air Force Office of Scientific Research under grant FA9550-22-1-0176. KS was supported by the Air Force Office of Scientific Research under grant (FA9550-22-1-0176) and the National Science Foundation under grant (DMS-2010046).","PeriodicalId":23598,"journal":{"name":"Waves in Random and Complex Media","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135975918","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 : 2023-11-02DOI: 10.1080/17455030.2022.2053242
V. Ostashev, Elena Shabalina, D. K. Wilson, Matthew J. Kamrath
The Markov approximation is widely used in wave propagation in random media. This approximation is valid if the propagation path length is greater than the scale of the medium inhomogeneities affecting a particular statistical moment of a wave field and the moment changes insignificantly over this scale. These conditions might be violated for the variance of the phase fluctuations and other statistical moments of acoustic signals that have propagated through atmospheric turbulence: the scale of the largest eddies can be hundreds of meters, and fluctuations in the acoustic refractive index are relatively strong. In the current article, the phase variance of a spherical sound wave in statistically inhomogeneous turbulence is formulated without the Markov approximation. For propagation ranges smaller than the scale of the largest eddies, the phase variance without the Markov approximation is significantly smaller than when this approximation is employed. As the range increases, the difference between the two results tends toward a constant value (a ‘memory’ effect), which might be significant in many applications. The phase variance without the Markov approximation agrees better with the experimental data on sound propagation through the atmosphere, while the variance calculated with this approximation significantly overpredicts the data.
{"title":"Non-Markov behavior of acoustic phase variance in the atmospheric boundary layer","authors":"V. Ostashev, Elena Shabalina, D. K. Wilson, Matthew J. Kamrath","doi":"10.1080/17455030.2022.2053242","DOIUrl":"https://doi.org/10.1080/17455030.2022.2053242","url":null,"abstract":"The Markov approximation is widely used in wave propagation in random media. This approximation is valid if the propagation path length is greater than the scale of the medium inhomogeneities affecting a particular statistical moment of a wave field and the moment changes insignificantly over this scale. These conditions might be violated for the variance of the phase fluctuations and other statistical moments of acoustic signals that have propagated through atmospheric turbulence: the scale of the largest eddies can be hundreds of meters, and fluctuations in the acoustic refractive index are relatively strong. In the current article, the phase variance of a spherical sound wave in statistically inhomogeneous turbulence is formulated without the Markov approximation. For propagation ranges smaller than the scale of the largest eddies, the phase variance without the Markov approximation is significantly smaller than when this approximation is employed. As the range increases, the difference between the two results tends toward a constant value (a ‘memory’ effect), which might be significant in many applications. The phase variance without the Markov approximation agrees better with the experimental data on sound propagation through the atmosphere, while the variance calculated with this approximation significantly overpredicts the data.","PeriodicalId":23598,"journal":{"name":"Waves in Random and Complex Media","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139291134","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 : 2023-11-02DOI: 10.1080/17455030.2022.2101073
Elizabeth Bleszynski, Marek Bleszynski, Thomas Jaroszewicz
AbstractWe describe an approach to detecting off-axis radiation of laser beams propagating in scattering media, especially in the atmosphere, in the presence of background (solar) radiation. The method relies on a generalization of the conventional intensity interferometry (II) theory to scenarios involving coexisting sources of relatively long (laser radiation) and much shorter (background) coherence times. In such circumstances, the high coherence of the laser light allows its discrimination against even much stronger, but low-coherence, background. We propose a simple detection system consisting of a small array of photodetectors (e.g. photodiodes) and estimate the ratio of the background-to-laser irradiances at which the laser radiation is expected to be detectable.Keywords: Laser radiationscatteringcoherencesolar backgroundintensity interferometry Disclosure statementNo potential conflict of interest was reported by the author(s).Notes1 Outweighed, at the time, by its insensitivity to detrimental effects of atmospheric turbulence, as discussed following Equation (Equation3(3) C(ϱ0):=⟨ΔJ(ϱ0/2)ΔJ(−ϱ0/2)⟩g(1)⟨(ΔJ(ϱ0/2))2⟩⟨(ΔJ(−ϱ0/2))2⟩≡⟨ΔJ+ΔJ−⟩g(1)⟨(ΔJ+)2⟩⟨(ΔJ−)2⟩,(3) ).2 In the definition (Equation2(2) δ=12ΔτηEA,(2) ) it is assumed that the aperture area is much smaller than the radiation's coherence area (as defined below, Equations (Equation55a(55a) ΔAjc=∫d2ϱFjc(ϱ)=π2Δϱjc∥Δϱjc⊥=λ2RπϕwjB≈1.27mm2(55a) )). In general, A has to be replaced with the aperture autocorrelation area, discussed in Section 3.3 We will, alternatively, express irradiance in units of watts per meter squared, by using the conversion factor 1W/m2=(λ/hc)photons/s≈7.5⋅1018photons/(sm2), the last numerical value corresponding to the SWIR wavelength λ=1.5μm.4 An exhaustive overview of the literature is given in the recent dissertation [Citation20].5 By a photosensor we mean a ‘single-pixel’ photodetector, such as a PIN photodiode, an avalanche photodiode, etc.6 Equation (Equation5(5) I±(t):=∫P±d2ϱ′|uP(t,ϱ′)|2≈∫Aj±d2ϱ|u(t,ϱ)|2,(5) ) implies that the ensemble average of the intensity is given by the surface integral of the irradiance.7 In fact, in SII one can also go beyond the approximations valid for very small apertures and introduce a ‘partial coherence factor’ Δ associated with larger apertures of the telescopes ([Citation27], Appendix A and [Citation2, p. 60]). Our Equations (Equation16b(16b) ⟨ΔI±(12τ)ΔI±(−12τ)⟩≈12|γ(τ)|2E2∫Aj±d2ϱ1∫A±d2ϱ2F(ϱ1−ϱ2)≡12|γ(τ)|2E2A±A¯±(16b) ) and (Equation16c(16c) ⟨ΔI+(12τ)ΔI−(−12τ)⟩≈12|γ(τ)|2E2∫Aj+d2ϱ1∫A−d2ϱ2F(ϱ1−ϱ2)≡12|γ(τ)|2E2g(1)A+A−A¯j+−,(16c) ) provide a generalization of these results.8 In the following, we will use either the frequency or the wavelength, always assuming ω=2πc/λ.9 We add here the superscript ϕ to emphasize the irradiance's dependence on the detector FOV.10 For reasons mentioned below, we neglect here L compared to R.11 We use here the symbol Jinc to differentiate this function from the conventional jinc(x)=2J1(πx)/(πx).12
{"title":"Detection of laser beams based on intensity interferometry","authors":"Elizabeth Bleszynski, Marek Bleszynski, Thomas Jaroszewicz","doi":"10.1080/17455030.2022.2101073","DOIUrl":"https://doi.org/10.1080/17455030.2022.2101073","url":null,"abstract":"AbstractWe describe an approach to detecting off-axis radiation of laser beams propagating in scattering media, especially in the atmosphere, in the presence of background (solar) radiation. The method relies on a generalization of the conventional intensity interferometry (II) theory to scenarios involving coexisting sources of relatively long (laser radiation) and much shorter (background) coherence times. In such circumstances, the high coherence of the laser light allows its discrimination against even much stronger, but low-coherence, background. We propose a simple detection system consisting of a small array of photodetectors (e.g. photodiodes) and estimate the ratio of the background-to-laser irradiances at which the laser radiation is expected to be detectable.Keywords: Laser radiationscatteringcoherencesolar backgroundintensity interferometry Disclosure statementNo potential conflict of interest was reported by the author(s).Notes1 Outweighed, at the time, by its insensitivity to detrimental effects of atmospheric turbulence, as discussed following Equation (Equation3(3) C(ϱ0):=⟨ΔJ(ϱ0/2)ΔJ(−ϱ0/2)⟩g(1)⟨(ΔJ(ϱ0/2))2⟩⟨(ΔJ(−ϱ0/2))2⟩≡⟨ΔJ+ΔJ−⟩g(1)⟨(ΔJ+)2⟩⟨(ΔJ−)2⟩,(3) ).2 In the definition (Equation2(2) δ=12ΔτηEA,(2) ) it is assumed that the aperture area is much smaller than the radiation's coherence area (as defined below, Equations (Equation55a(55a) ΔAjc=∫d2ϱFjc(ϱ)=π2Δϱjc∥Δϱjc⊥=λ2RπϕwjB≈1.27mm2(55a) )). In general, A has to be replaced with the aperture autocorrelation area, discussed in Section 3.3 We will, alternatively, express irradiance in units of watts per meter squared, by using the conversion factor 1W/m2=(λ/hc)photons/s≈7.5⋅1018photons/(sm2), the last numerical value corresponding to the SWIR wavelength λ=1.5μm.4 An exhaustive overview of the literature is given in the recent dissertation [Citation20].5 By a photosensor we mean a ‘single-pixel’ photodetector, such as a PIN photodiode, an avalanche photodiode, etc.6 Equation (Equation5(5) I±(t):=∫P±d2ϱ′|uP(t,ϱ′)|2≈∫Aj±d2ϱ|u(t,ϱ)|2,(5) ) implies that the ensemble average of the intensity is given by the surface integral of the irradiance.7 In fact, in SII one can also go beyond the approximations valid for very small apertures and introduce a ‘partial coherence factor’ Δ associated with larger apertures of the telescopes ([Citation27], Appendix A and [Citation2, p. 60]). Our Equations (Equation16b(16b) ⟨ΔI±(12τ)ΔI±(−12τ)⟩≈12|γ(τ)|2E2∫Aj±d2ϱ1∫A±d2ϱ2F(ϱ1−ϱ2)≡12|γ(τ)|2E2A±A¯±(16b) ) and (Equation16c(16c) ⟨ΔI+(12τ)ΔI−(−12τ)⟩≈12|γ(τ)|2E2∫Aj+d2ϱ1∫A−d2ϱ2F(ϱ1−ϱ2)≡12|γ(τ)|2E2g(1)A+A−A¯j+−,(16c) ) provide a generalization of these results.8 In the following, we will use either the frequency or the wavelength, always assuming ω=2πc/λ.9 We add here the superscript ϕ to emphasize the irradiance's dependence on the detector FOV.10 For reasons mentioned below, we neglect here L compared to R.11 We use here the symbol Jinc to differentiate this function from the conventional jinc(x)=2J1(πx)/(πx).12 ","PeriodicalId":23598,"journal":{"name":"Waves in Random and Complex Media","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135975921","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 : 2023-11-02DOI: 10.1080/17455030.2022.2081376
Guo-Min Yang, Xiaoyi Wang, Ya-Qiu Jin
AbstractCoding metasurfaces, characterized by processing the electromagnetic waves for specified functions through predesigned coding sequences either in space or time, can manipulate the electromagnetic waves in both space frequencies and time frequencies. They have been emerging as the revolutionary platforms for metasurface technologies in recent years. In this paper, we first introduce the general concept and operating principle of the coding metasurfaces. Then, two design strategies for realizing the coding metasurface particles, altering resonant states and switching current phase, are provided, respectively. Next, two recent reported applications that are based on space-coding metasurface for RCS reduction and time-coding metasurface for spread-spectrum wireless communication are presented, respectively. Finally, existing challenges and potential future research directions in coding metasurfaces are discussed.Keywords: Coding metasurfacespace-codingtime-codingspace-time-codingmulti-bitRCS reductionspread spectrum AcknowledgmentsThe authors would like to thank Dr. Fuheng Zhang, Dr. Yasir Saifullah, and Qingzhuo Chen for their valuable contribution to this work.Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingThis work was supported by the National Key Research and Development Program of China under grant number 2017YFA0100203.
{"title":"Concept, realization, and applications of coding metasurfaces","authors":"Guo-Min Yang, Xiaoyi Wang, Ya-Qiu Jin","doi":"10.1080/17455030.2022.2081376","DOIUrl":"https://doi.org/10.1080/17455030.2022.2081376","url":null,"abstract":"AbstractCoding metasurfaces, characterized by processing the electromagnetic waves for specified functions through predesigned coding sequences either in space or time, can manipulate the electromagnetic waves in both space frequencies and time frequencies. They have been emerging as the revolutionary platforms for metasurface technologies in recent years. In this paper, we first introduce the general concept and operating principle of the coding metasurfaces. Then, two design strategies for realizing the coding metasurface particles, altering resonant states and switching current phase, are provided, respectively. Next, two recent reported applications that are based on space-coding metasurface for RCS reduction and time-coding metasurface for spread-spectrum wireless communication are presented, respectively. Finally, existing challenges and potential future research directions in coding metasurfaces are discussed.Keywords: Coding metasurfacespace-codingtime-codingspace-time-codingmulti-bitRCS reductionspread spectrum AcknowledgmentsThe authors would like to thank Dr. Fuheng Zhang, Dr. Yasir Saifullah, and Qingzhuo Chen for their valuable contribution to this work.Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingThis work was supported by the National Key Research and Development Program of China under grant number 2017YFA0100203.","PeriodicalId":23598,"journal":{"name":"Waves in Random and Complex Media","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135975601","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 : 2023-11-02DOI: 10.1080/17455030.2023.2172959
Saba Mudaliar
AbstractIn this paper, we carried out a critical investigation of the strong fluctuation theory using a quantum field theoretic approach [Tatarskii VI. The effects of the turbulent atmosphere on wave propagation. Jerusalem: IPST; 1971]. We employed the Dyson and Bethe-Salpeter equations to derive the radiative transfer equation (RTE) for the Green's function of the radiant intensity. We proceeded to obtain estimates of the domain of validity of the RTE. The results thus obtained satisfy both the optical theorem for waves in random media and energy conservation. We also derived the RTE for our problem by employing a recently developed scale-separated asymptotic theory [Bal G., Komorowski T, Ryzhik L. Kinetic limits of waves in random media. Kinet Relat Models. 2010;3:529–644]. Although the RTE obtained by the two approaches are identical, we explain that the applicability regimes, and hence validity conditions are different.Keywords: Quantum field theoretic approachstrong fluctuation theoryscale-separated asymptoticsradiative transfer equationsrandom media Disclosure statementNo potential conflict of interest was reported by the author(s).Notes1 Dˆ1 and Dˆ2 are Dyson operators (cf. (Equation3(3) DˆGm=−δ(r−r′)(3) )) corresponding to spatial variables r1 and r2, respectively.2 by directly employing the governing equations of scaled Green's functions and their Wigner transforms
{"title":"Strong fluctuation theory of Tatarskii: quantum field theoretic approach – a critical assessment","authors":"Saba Mudaliar","doi":"10.1080/17455030.2023.2172959","DOIUrl":"https://doi.org/10.1080/17455030.2023.2172959","url":null,"abstract":"AbstractIn this paper, we carried out a critical investigation of the strong fluctuation theory using a quantum field theoretic approach [Tatarskii VI. The effects of the turbulent atmosphere on wave propagation. Jerusalem: IPST; 1971]. We employed the Dyson and Bethe-Salpeter equations to derive the radiative transfer equation (RTE) for the Green's function of the radiant intensity. We proceeded to obtain estimates of the domain of validity of the RTE. The results thus obtained satisfy both the optical theorem for waves in random media and energy conservation. We also derived the RTE for our problem by employing a recently developed scale-separated asymptotic theory [Bal G., Komorowski T, Ryzhik L. Kinetic limits of waves in random media. Kinet Relat Models. 2010;3:529–644]. Although the RTE obtained by the two approaches are identical, we explain that the applicability regimes, and hence validity conditions are different.Keywords: Quantum field theoretic approachstrong fluctuation theoryscale-separated asymptoticsradiative transfer equationsrandom media Disclosure statementNo potential conflict of interest was reported by the author(s).Notes1 Dˆ1 and Dˆ2 are Dyson operators (cf. (Equation3(3) DˆGm=−δ(r−r′)(3) )) corresponding to spatial variables r1 and r2, respectively.2 by directly employing the governing equations of scaled Green's functions and their Wigner transforms","PeriodicalId":23598,"journal":{"name":"Waves in Random and Complex Media","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135975600","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 : 2023-11-02DOI: 10.1080/17455030.2022.2116661
Hang Wang, Reza Abedi, Saba Mudaliar
AbstractThe radiative transfer equation (RTE) is an integro-differential equation that describes the radiation energy absorbing, emitting, and scattering in both space and angle, which can be up to five-dimensional problems. It is difficult for a RTE solver to satisfy both accuracy and efficiency (less computational resources) for such high dimensional problems. In this paper, an iterative solver for one-dimensional cylindrical radiative transfer problems using the space-angle discontinuous Galerkin (DG) method is developed to achieve both accuracy and efficiency. The iterative solver is based on the angular decomposition (AD) scheme, which slices the spatial-angular domain into slabs and decouples the angular integration between slabs. Both Jacobi and successive over-relaxation (SOR) iterative schemes are investigated by numerical analysis and examples. The comparison of the two iterative schemes suggests that an appropriate relaxation factor for the SOR method may accelerate the convergence. Finally, the iterative scheme is more efficient than the direct solution of the system both in terms of memory usage and computational time, especially for finer meshes.Keywords: Radiate transfer equationdiscontinuous galerkinspace-angleiterative schemejacobi methodsuccessive over-relaxation methodangular decomposition Disclosure statementNo potential conflict of interest was reported by the author(s).
{"title":"Iterative space-angle discontinuous Galerkin method for radiative transfer equation","authors":"Hang Wang, Reza Abedi, Saba Mudaliar","doi":"10.1080/17455030.2022.2116661","DOIUrl":"https://doi.org/10.1080/17455030.2022.2116661","url":null,"abstract":"AbstractThe radiative transfer equation (RTE) is an integro-differential equation that describes the radiation energy absorbing, emitting, and scattering in both space and angle, which can be up to five-dimensional problems. It is difficult for a RTE solver to satisfy both accuracy and efficiency (less computational resources) for such high dimensional problems. In this paper, an iterative solver for one-dimensional cylindrical radiative transfer problems using the space-angle discontinuous Galerkin (DG) method is developed to achieve both accuracy and efficiency. The iterative solver is based on the angular decomposition (AD) scheme, which slices the spatial-angular domain into slabs and decouples the angular integration between slabs. Both Jacobi and successive over-relaxation (SOR) iterative schemes are investigated by numerical analysis and examples. The comparison of the two iterative schemes suggests that an appropriate relaxation factor for the SOR method may accelerate the convergence. Finally, the iterative scheme is more efficient than the direct solution of the system both in terms of memory usage and computational time, especially for finer meshes.Keywords: Radiate transfer equationdiscontinuous galerkinspace-angleiterative schemejacobi methodsuccessive over-relaxation methodangular decomposition Disclosure statementNo potential conflict of interest was reported by the author(s).","PeriodicalId":23598,"journal":{"name":"Waves in Random and Complex Media","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135975603","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 : 2023-11-02DOI: 10.1080/17455030.2022.2061083
Dimitriy A. Marakasov, Victor A. Banakh, Artem A. Sukharev, Ruvim Sh. Tsvyk
AbstractThe paper analyzes the spatial distribution of the average air density in a supersonic jet based on the results of laser transillumination. The algorithm to retrieve the average air density from transverse (to the jet axis) deviations of the transilluminating wavefront was tested in experiments on the Vertical jet setup of ITAM SB RAS. The results of retrieval are compared with the known literature data of contact measurements and with results of numerical simulation. The good sensitivity of local wavefront tilts to oscillations in the air density at frequencies of discrete acoustic tones has been demonstrated. This opens up the possibility of experimental study of the spatial structure of air density inhomogeneities in the jet channel.KEYWORDS: Supersonic jetlaser transilluminationwavefront distortionsair densityreconstruction AcknowledgementsThe authors are grateful to the colleagues of the ITAM SB RAS: Dr. V.I. Zapryagaev, Dr. N.P. Kiselev, and V.V. Bashurov for their help in organizing the experiment.Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingThis work was supported by the Ministry of Science and Higher Education of the Russian Federation (V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Sciences).
{"title":"Study of the structure of turbulent underexpanded supersonic jets by laser transillumination","authors":"Dimitriy A. Marakasov, Victor A. Banakh, Artem A. Sukharev, Ruvim Sh. Tsvyk","doi":"10.1080/17455030.2022.2061083","DOIUrl":"https://doi.org/10.1080/17455030.2022.2061083","url":null,"abstract":"AbstractThe paper analyzes the spatial distribution of the average air density in a supersonic jet based on the results of laser transillumination. The algorithm to retrieve the average air density from transverse (to the jet axis) deviations of the transilluminating wavefront was tested in experiments on the Vertical jet setup of ITAM SB RAS. The results of retrieval are compared with the known literature data of contact measurements and with results of numerical simulation. The good sensitivity of local wavefront tilts to oscillations in the air density at frequencies of discrete acoustic tones has been demonstrated. This opens up the possibility of experimental study of the spatial structure of air density inhomogeneities in the jet channel.KEYWORDS: Supersonic jetlaser transilluminationwavefront distortionsair densityreconstruction AcknowledgementsThe authors are grateful to the colleagues of the ITAM SB RAS: Dr. V.I. Zapryagaev, Dr. N.P. Kiselev, and V.V. Bashurov for their help in organizing the experiment.Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingThis work was supported by the Ministry of Science and Higher Education of the Russian Federation (V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Sciences).","PeriodicalId":23598,"journal":{"name":"Waves in Random and Complex Media","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135975923","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 : 2023-11-02DOI: 10.1080/17455030.2023.2276730
Kamel Cheriet, Yassine Demagh, El Wardi Bitam, Farid Berrahil
AbstractCompared to helically coiled tube exchangers (HCTs), longitudinally curved tube exchangers (LCTs) have received little attention from scientists over the past decade, leading to a lack of correlations estimating the Nusselt number and friction factor. In view of recent studies promoting the use of LCTs (waved, C-shaped or sinusoidal) in linear solar concentrating systems, this study examines whether or not correlations of and developed explicitly for HCTs could be applied to LCTs. A (SST) turbulent model has been run on HCTs and validated by experimental correlations from the literature. With an amplitude ratio equal to unity (waviness amplitude to the curvature radius ratio) and the same curvature ratio (tube radius to the curvature radius ratio), LCTs and HCTs are geometrically similar. For these similar configurations, the numerical results of over the Reynolds number range overlap almost perfectly, which is not for. Over the LTC amplitude ratio range, no significant change in the mean was reported, with a max relative error of 3.98%, whereas was highly dependent on it. One key finding: with a similar curvature ratio, correlations of the mean developed previously for HCTs could be used for LCTs, which is not valid for the mean.KEYWORDS: Nusselt numberfriction factorhelically coiled tubelongitudinally C-curved tubesimilaritiesnumerical simulation Disclosure statementNo potential conflict of interest was reported by the author(s).
{"title":"Thermal performance analysis of coils versus longitudinal C-shaped tubes: validity of the turbulent correlations","authors":"Kamel Cheriet, Yassine Demagh, El Wardi Bitam, Farid Berrahil","doi":"10.1080/17455030.2023.2276730","DOIUrl":"https://doi.org/10.1080/17455030.2023.2276730","url":null,"abstract":"AbstractCompared to helically coiled tube exchangers (HCTs), longitudinally curved tube exchangers (LCTs) have received little attention from scientists over the past decade, leading to a lack of correlations estimating the Nusselt number and friction factor. In view of recent studies promoting the use of LCTs (waved, C-shaped or sinusoidal) in linear solar concentrating systems, this study examines whether or not correlations of and developed explicitly for HCTs could be applied to LCTs. A (SST) turbulent model has been run on HCTs and validated by experimental correlations from the literature. With an amplitude ratio equal to unity (waviness amplitude to the curvature radius ratio) and the same curvature ratio (tube radius to the curvature radius ratio), LCTs and HCTs are geometrically similar. For these similar configurations, the numerical results of over the Reynolds number range overlap almost perfectly, which is not for. Over the LTC amplitude ratio range, no significant change in the mean was reported, with a max relative error of 3.98%, whereas was highly dependent on it. One key finding: with a similar curvature ratio, correlations of the mean developed previously for HCTs could be used for LCTs, which is not valid for the mean.KEYWORDS: Nusselt numberfriction factorhelically coiled tubelongitudinally C-curved tubesimilaritiesnumerical simulation Disclosure statementNo potential conflict of interest was reported by the author(s).","PeriodicalId":23598,"journal":{"name":"Waves in Random and Complex Media","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135972912","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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