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Absorbing Boundary Conditions for Simulating Water Waves Near Solid Bodies
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作者 José Marie Orellana 《Journal of Applied Mathematics and Physics》 2024年第10期3502-3520,共19页
The objective of this paper is to present a new method for designing absorbing or non-reflective boundary conditions (ABC) or (NRBC), illustrated by the case study of the modelling of a solid body in water, specifical... The objective of this paper is to present a new method for designing absorbing or non-reflective boundary conditions (ABC) or (NRBC), illustrated by the case study of the modelling of a solid body in water, specifically the capillary gravity waves generated by its motion at the surface. The study analyses the flow of an inviscid, barotropic, and compressible fluid around the stationary solid body. The dynamic behaviour of the fluid is analysed using a two-dimensional coupled Neumann-Kelvin model extended with capillarity and inertia terms. For computational purposes, it is necessary to truncate the unbounded spatial domain with artificial boundaries and then introduce appropriate absorbing boundary conditions. The propagation of short wavelength waves in a convective fluid medium with significant differences in properties between the interior and the surface of the fluid presents a number of difficulties in the design of these conditions. The results are illustrated numerically and commented upon. 展开更多
关键词 absorbing Boundary Condition Fluid-Structure Interaction Capillary-Gravity Waves Numerical Simulations
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A joint absorbing boundary for the multiple-relaxation-time lattice Boltzmann method in seismic acoustic wavefield modeling 被引量:1
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作者 Chun-Tao Jiang Hui Zhou +2 位作者 Mu-Ming Xia Han-Ming Chen Jin-Xuan Tang 《Petroleum Science》 SCIE EI CAS CSCD 2023年第4期2113-2126,共14页
Conventional seismic wave forward simulation generally uses mathematical means to solve the macroscopic wave equation,and then obtains the corresponding seismic wavefield.Usually,when the subsurface structure is finel... Conventional seismic wave forward simulation generally uses mathematical means to solve the macroscopic wave equation,and then obtains the corresponding seismic wavefield.Usually,when the subsurface structure is finely constructed and the continuity of media is poor,this strategy is difficult to meet the requirements of accurate wavefield calculation.This paper uses the multiple-relaxation-time lattice Boltzmann method(MRT-LBM)to conduct the seismic acoustic wavefield simulation and verify its computational accuracy.To cope with the problem of severe reflections at the truncated boundaries,we analogize the viscous absorbing boundary and perfectly matched layer(PML)absorbing boundary based on the single-relaxation-time lattice Boltzmann(SRT-LB)equation to the MRT-LB equation,and further,propose a joint absorbing boundary through comparative analysis.We give the specific forms of the modified MRT-LB equation loaded with the joint absorbing boundary in the two-dimensional(2D)and three-dimensional(3D)cases,respectively.Then,we verify the effects of this absorbing boundary scheme on a 2D homogeneous model,2D modified British Petroleum(BP)gas-cloud model,and 3D homogeneous model,respectively.The results reveal that by comparing with the viscous absorbing boundary and PML absorbing boundary,the joint absorbing boundary has the best absorption performance,although it is a little bit complicated.Therefore,this joint absorbing boundary better solves the problem of truncated boundary reflections of MRT-LBM in simulating seismic acoustic wavefields,which is pivotal to its wide application in the field of exploration seismology. 展开更多
关键词 Multiple-relaxation-time Lattice Boltzmann method Seismic acoustic wavefield simulation Truncated Boundary reflection Joint absorbing boundary
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Editorial for special issue on electromagnetic wave absorbing materials 被引量:1
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作者 Guanglei Wu Hongjing Wu Zirui Jia 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第3期401-404,共4页
With the rapid development of information technology and electronics industry,stealth warplanes,radar stealth,electronic countermeasures,microwave communications,and other equipment have played an increasingly importa... With the rapid development of information technology and electronics industry,stealth warplanes,radar stealth,electronic countermeasures,microwave communications,and other equipment have played an increasingly important role in military defense.Therefore,the design and development of new electromagnetic wave(EMW)absorbing materials with high performance and environmental applicability that can be widely used in the microwave field has become a key issue and a major strategic challenge that needs to be urgently addressed in the modernization and upgrading of major advanced military equipment.However,how to effectively address the growing electromagnetic pollution has been an important issue that has plagued researchers in the field of EMW absorption for many years. 展开更多
关键词 absorbing MICROWAVE WAVE
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Lightweight broadband microwave absorbing metamaterial with CB-ABS composites fabricated by 3D printing 被引量:1
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作者 陈孟州 汪刘应 +3 位作者 刘顾 葛超群 李涤尘 梁庆宣 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第4期691-695,共5页
The self-similarity,high geometric symmetry and spatial utilization properties of fractal structures provide new methods for the development of absorbing metamaterials.In this paper,the microwave absorption properties... The self-similarity,high geometric symmetry and spatial utilization properties of fractal structures provide new methods for the development of absorbing metamaterials.In this paper,the microwave absorption properties of the gradient dendritic fractal metamaterial structure(GDFMs)based on carbon black and acrylonitrile-butadiene-styrene composites were investigated.The optimal metamaterial structure has an effective absorption in the frequency range of 4.5-40 GHz.The rotational-symmetry GDFMs leads to the polarization independence,and the GDFMs exhibits a wide-angle absorption performance for both TE and TM waves.It is expected that the proposed GDFMs has good application prospects in electromagnetic wave absorption. 展开更多
关键词 additive manufacturing broadband absorbing polarization and angle independence gradient dendritic fractal structure
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Preparation and Microwave Absorbing Properties of Double-layer Fine Iron Tailings Cementitious Materials
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作者 LI Huawei WANG Rong +3 位作者 WANG Yulin LIU Feiyu WANG Qian WEI Muwang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第5期1126-1135,共10页
To develop the microwave absorbing(MA)properties of cementitious material mixed with mine solid waste,the iron tailings cementitious microwave absorbing materials were prepared.The iron tailings was treated into diffe... To develop the microwave absorbing(MA)properties of cementitious material mixed with mine solid waste,the iron tailings cementitious microwave absorbing materials were prepared.The iron tailings was treated into different particle sizes by planetary ball mill,and the physicochemical properties of iron tailings were tested by laser particle size analyzer and scanning electron microscope(SEM).The electromagnetic parameters of iron tailings cementitious materials were characterized by a vector network analyzer and simulated MA properties,and the MA properties of iron tailings-cement composite system with steel fiber as absorber was studied.Based on the design of the single-layer structure,optimum mix ratio and thickness configuration method of double-layer structure were further studied,meanwhile,the mechanical properties and engineering application were analyzed and discussed.The results show that the particle size of iron tailings can afiect its electromagnetic behavior in cementitious materials,and the smaller particles lead the increase of demagnetisation efiect induced by domain wall motion and achieve better microwave absorbing properties in cementitious materials.When the thickness of matching layer and absorbing layer is 5 mm,the optimized microwave absorbing properties of C1/C3 double-layer cementitious material can obtain optimal RL value of-27.61 dB and efiective absorbing bandwidth of 0.97 GHz,which attributes to the synergistic efiect of impedance matching and attenuation characteristics.The double-layer microwave absorbing materials obtain excellent absorbing properties and show great design flexibility and diversity,which can be used as a suitable candidate for the preparation of favorable microwave absorbing cementitious materials. 展开更多
关键词 microwave absorbing properties iron tailings electromagnetic parameters single-layer structure double-layer structure impedance matching
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Hybrid absorbing boundary condition based on transmitting boundary and its application in 3D fractional viscoacoustic modeling
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作者 Song-Ling Li Ying Shi +2 位作者 Ning Wang Wei-Hong Wang Xuan Ke 《Petroleum Science》 SCIE EI CAS CSCD 2023年第2期840-856,共17页
An accurate numerical simulation for wave equations is essential for understanding of wave propagation in the earth's interior as well as full waveform inversion and reverse time migration. However, due to computa... An accurate numerical simulation for wave equations is essential for understanding of wave propagation in the earth's interior as well as full waveform inversion and reverse time migration. However, due to computational cost and hardware capability limitations, numerical simulations are often performed within a finite domain. Thus, an adequate absorbing boundary condition (ABC) is indispensable for obtaining accurate numerical simulation results. In this study, we develop a hybrid ABC based on a transmitting boundary, which is referred to as THABC, to eliminate artificial boundary reflections in 3D second-order fractional viscoacoustic numerical simulations. Furthermore, we propose an adaptive weighted coefficient to reconcile the transmitting and viscoacoustic wavefields in THABC. Through several numerical examples, we determine that the proposed THABC approach is characterized by the following benefits. First, with the same number of absorbing layers, THABC exhibits a better ability in eliminating boundary reflection than traditional ABC schemes. Second, THABC is more effective in computation, since it only requires the wavefields at the current and last time steps to solve the transmitting formula within the absorbing layers. Benefiting from a simple but effective combination between the transmitting equation and the second-order wave equation, our scheme performs well in the 3D fractional Laplacian viscoacoustic numerical simulation. 展开更多
关键词 Hybrid absorbing boundary Numerical simulation Transmitting boundary Fractional viscoacoustic wave equation
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Constructing BaTiO_(3)/TiO_(2)@polypyrrole composites with hollow multishelled structure for enhanced electromagnetic wave absorbing properties
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作者 Dan Mao Zhen Zhang +3 位作者 Mei Yang Zumin Wang Ranbo Yu Dan Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第3期581-590,共10页
BaTiO_(3)/TiO_(2)@polypyrrole(PPy)composites with hollow multishelled structure(HoMS)were constructed to enhance the electromagnetic wave absorbing properties of BaTiO_(3)-based absorbing material.BaTiO_(3)/TiO_(2)HoM... BaTiO_(3)/TiO_(2)@polypyrrole(PPy)composites with hollow multishelled structure(HoMS)were constructed to enhance the electromagnetic wave absorbing properties of BaTiO_(3)-based absorbing material.BaTiO_(3)/TiO_(2)HoMSs were prepared by hydrothermal crystallization using TiO_(2)Ho MSs as template.Then,FeCl3 was introduced to initiate the oxidative polymerization of pyrrole monomer,forming BaTiO_(3)/TiO_(2)@PPy HoMSs successfully.The electromagnetic wave absorbing properties of BaTiO_(3)/TiO_(2)HoMSs and BaTiO_(3)/TiO_(2)@PPy Ho MSs with different shell number were investigated using a vector network analyzer.The results indicate that BaTiO_(3)/TiO_(2)@PPy HoMSs exhibit improved microwave absorption compared with BaTiO_(3)/TiO_(2)HoMSs.In particular,tripled-shelled BaTiO_(3)/TiO_(2)@PPy HoMS has the most excellent absorbing performance.The best reflection loss can reach up to-21.80 dB at 13.34 GHz with a corresponding absorber thickness of only 1.3 mm,and the qualified absorption bandwidth of tripled-shelled BaTiO_(3)/TiO_(2)@PPy HoMS is up to 4.2 GHz.This work paves a new way for the development of high-performance composite microwave absorbing materials. 展开更多
关键词 BaTiO_(3)/TiO_(2)@polypyrrole composites hollow multishelled structure electromagnetic wave absorbing
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Calculation and Analysis of Acoustic Characteristics of Straight-Through Perforated Pipe Muffler Based on Multilayer Sound Absorbing Material
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作者 刘镕基 朱从云 +1 位作者 丁国芳 院蕾 《Journal of Donghua University(English Edition)》 CAS 2023年第5期506-514,共9页
Using the multi-physical field simulation software COMSOL,the acoustic characteristics of the multilayer sound absorbing material straight-through perforated pipe muffler are studied by the finite element method.The r... Using the multi-physical field simulation software COMSOL,the acoustic characteristics of the multilayer sound absorbing material straight-through perforated pipe muffler are studied by the finite element method.The results show that the finite element calculation of the multilayer sound absorbing material straight-through the perforated pipe muffler agrees well with the experimental measurement results.The reliability of the finite element method for studying the acoustic performance of the straight-through perforated pipe muffler with multilayer sound absorbing materials is shown.Furthermore,the influence of some structural parameters of porous sound absorbing material and micro-perforated plate on the acoustic performance of the multilayer sound absorbing material straight-through perforated pipe muffler is analyzed.The muffler based on multilayer sound absorbing material is different from the traditional muffler.After applying the multilayer sound absorbing material to the straight-through perforated pipe muffler,the transmission loss value greatly increases,which provides new ideas and directions for future research on the muffler. 展开更多
关键词 porous sound absorbing material perforated tube finite element method MUFFLER acoustic characteristics
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Effects of thermal oxidation on microwave-absorbing and mechanical properties of SiC_f/SiC composites with PyC interphase 被引量:2
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作者 史毅敏 罗发 +3 位作者 丁冬海 穆阳 周万城 朱冬梅 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第5期1484-1489,共6页
The SiCf/SiC composites containing PyC interphase were prepared by chemical vapor infiltration process. The influences of thermal oxidation on the complex permittivity and microwave absorption properties of Si Cf/Si C... The SiCf/SiC composites containing PyC interphase were prepared by chemical vapor infiltration process. The influences of thermal oxidation on the complex permittivity and microwave absorption properties of Si Cf/Si C composites were investigated in the frequency range of 8.2-12.4 GHz. Both the real and imaginary parts of the complex permittivity decreased after thermal oxidation. The composites after 100 h thermal oxidation showed that reflection loss exceeded-10 d B in the frequency of 9.7-11.9 GHz and the minimum value was-11.4 d B at 11.0 GHz. The flexural strength of composites decreased but fracture behavior was improved obviously after thermal oxidation. These results indicate that the SiCf/SiC composites containing PyC interphase after thermal oxidation possess good microwave absorbing property and fracture behavior. 展开更多
关键词 SiCf/SiC composites thermal oxidation dielectric properties microwave absorbing mechanical properties
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Effects of Different Absorbing Medium on Microwave Remediation of Chlordane Contaminated Soil 被引量:2
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作者 赵浩 周荣 +3 位作者 赵敏燕 王世强 任朋 徐炎华 《Agricultural Science & Technology》 CAS 2015年第4期750-754,共5页
Objective] This study almed to compare the effects of three absorbing medium on microwave degradation of chIordane in contaminated soiI under alkaline condition. [Method] SoiI sampIes were coI ected from the original ... Objective] This study almed to compare the effects of three absorbing medium on microwave degradation of chIordane in contaminated soiI under alkaline condition. [Method] SoiI sampIes were coI ected from the original site of a reIocated pesticide production enterprise as experimental materials, to investigate the effects of Cu2O, MnO2 and activated carbon powder as absorbing medium on soiI warming and removal rate of chIordane under alkaline condition with 20% moisture content. In addition, the effects of activated carbon as the optimal absorbing media on the removal rate of chIordane in contaminated soiI were analyzed, and the effects on the removal rate of chIordane in different weights of soiI sampIes were investigated. [Result] The effects of three different absorbing medium on the removal rates of chIordane demonstrated a descending order of activated carbon &gt; MnO2 &gt; CuO2. Under the same microwave condition, the removal rate of chIordane decreased with the increase of soiI weights, but the utiIization efficiency of microwave was improved continuousIy and tended to be stabiIized with the increase of soiI weights. [Conclu-sion] This study provided a theoretical basis for further Iarge-scale appIication in soiI remediation. 展开更多
关键词 CHLORDANE absorbing medium MICROWAVE Remedlatlon SOLI
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Magnetic and microwave absorbing properties of M-type barium ferrite/graphene oxide composite microwave absorber 被引量:1
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作者 荆洪阳 唐梦茹 +2 位作者 韩永典 徐连勇 李敏 《Journal of Southeast University(English Edition)》 EI CAS 2015年第4期511-515,共5页
In order to improve the absorbing properties of M- type barium ferrite absorbing materials, M-type barium ferrite/graphene oxide composites with different graphene oxide contents were synthesized by the sol-gel autoco... In order to improve the absorbing properties of M- type barium ferrite absorbing materials, M-type barium ferrite/graphene oxide composites with different graphene oxide contents were synthesized by the sol-gel autocombustion method. X-ray diffraction (XRD), a scanning electronic microscopy ( SEM ), a physical properties measurement system (PPMS-9), and a vector network analyzer were used to analyze their structure, surface morphology, magnetic and absorbing properties, respectively. The results show that the absorbing band of the composite absorbing material is widened and the absorbing strength is increased compared with the pure M-type barium ferrite. The sample with the content of doped graphene oxide of 3% has the minimum reflectivity at 10 to 18 GHz frequencies. Hence, the doped graphene oxide effectively improves the absorbing properties of M-type barium ferrite. 展开更多
关键词 M-type barium ferrite graphene oxide composite microwave absorber magnetic property microwave absorbing property
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Application of the double absorbing boundary condition in seismic modeling 被引量:1
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作者 刘洋 李向阳 陈双全 《Applied Geophysics》 SCIE CSCD 2015年第1期111-119,123,共10页
We apply the newly proposed double absorbing boundary condition(DABC)(Hagstrom et al., 2014) to solve the boundary reflection problem in seismic finite-difference(FD) modeling. In the DABC scheme, the local high... We apply the newly proposed double absorbing boundary condition(DABC)(Hagstrom et al., 2014) to solve the boundary reflection problem in seismic finite-difference(FD) modeling. In the DABC scheme, the local high-order absorbing boundary condition is used on two parallel artificial boundaries, and thus double absorption is achieved. Using the general 2D acoustic wave propagation equations as an example, we use the DABC in seismic FD modeling, and discuss the derivation and implementation steps in detail. Compared with the perfectly matched layer(PML), the complexity decreases, and the stability and fl exibility improve. A homogeneous model and the SEG salt model are selected for numerical experiments. The results show that absorption using the DABC is considerably improved relative to the Clayton–Engquist boundary condition and nearly the same as that in the PML. 展开更多
关键词 Double absorbing boundary condition numerical modeling finite-difference method artificial boundary condition
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Perfectly matched layer-absorbing boundary condition for finite-element time-domain modeling of elastic wave equations 被引量:3
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作者 赵建国 史瑞其 《Applied Geophysics》 SCIE CSCD 2013年第3期323-336,359,共15页
The perfectly matched layer (PML) is a highly efficient absorbing boundary condition used for the numerical modeling of seismic wave equation. The article focuses on the application of this technique to finite-eleme... The perfectly matched layer (PML) is a highly efficient absorbing boundary condition used for the numerical modeling of seismic wave equation. The article focuses on the application of this technique to finite-element time-domain numerical modeling of elastic wave equation. However, the finite-element time-domain scheme is based on the second- order wave equation in displacement formulation. Thus, the first-order PML in velocity-stress formulation cannot be directly applied to this scheme. In this article, we derive the finite- element matrix equations of second-order PML in displacement formulation, and accomplish the implementation of PML in finite-element time-domain modeling of elastic wave equation. The PML has an approximate zero reflection coefficients for bulk and surface waves in the finite-element modeling of P-SV and SH wave propagation in the 2D homogeneous elastic media. The numerical experiments using a two-layer model with irregular topography validate the efficiency of PML in the modeling of seismic wave propagation in geological models with complex structures and heterogeneous media. 展开更多
关键词 absorbing boundary condition elastic wave equation perfectly matched layer finite-element modeling
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Improved absorbing boundary condition based on linear interpolation for ADI-FDTD method 被引量:1
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作者 赵嘉宁 《Journal of Southeast University(English Edition)》 EI CAS 2009年第3期289-293,共5页
With the linear interpolation method, an improved absorbing boundary condition(ABC)is introduced and derived, which is suitable for the alternating-direction-implicit finite- difference time-domain (ADI-FDTD) meth... With the linear interpolation method, an improved absorbing boundary condition(ABC)is introduced and derived, which is suitable for the alternating-direction-implicit finite- difference time-domain (ADI-FDTD) method. The reflection of the ABC caused by both the truncated error and the phase velocity error is analyzed. Based on the phase velocity estimation and the nonuniform cell, two methods are studied and then adopted to improve the performance of the ABC. A calculation case of a rectangular waveguide which is a typical dispersive transmission line is carried out using the ADI-FDTD method with the improved ABC for evaluation. According to the calculated case, the comparison is given between the reflection coefficients of the ABC with and without the velocity estimation and also the comparison between the reflection coefficients of the ABC with and without the nonuniform processing. The reflection variation of the ABC under different time steps is also analyzed and the acceptable worsening will not obscure the improvement on the absorption. Numerical results obviously show that efficient improvement on the absorbing performance of the ABC is achieved based on these methods for the ADI-FDTD. 展开更多
关键词 alternating-direction-implicit finite-difference time- domain ADI-FDTD method absorbing boundary condition (ABC) linear interpolation phase velocity nonuniform cell
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The implementation of an improved NPML absorbing boundary condition in elastic wave modeling 被引量:21
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作者 Qin Zhen Lu Minghui +3 位作者 Zheng Xiaodong Yao Yao Zhang Cai Song Jianyong 《Applied Geophysics》 SCIE CSCD 2009年第2期113-121,共9页
In elastic wave forward modeling, absorbing boundary conditions (ABC) are used to mitigate undesired reflections from the model truncation boundaries. The perfectly matched layer (PML) has proved to be the best av... In elastic wave forward modeling, absorbing boundary conditions (ABC) are used to mitigate undesired reflections from the model truncation boundaries. The perfectly matched layer (PML) has proved to be the best available ABC. However, the traditional splitting PML (SPML) ABC has some serious disadvantages: for example, global SPML ABCs require much more computing memory, although the implementation is easy. The implementation of local SPML ABCs also has some difficulties, since edges and corners must be considered. The traditional non-splitting perfectly matched layer (NPML) ABC has complex computation because of the convolution. In this paper, based on non-splitting perfectly matched layer (NPML) ABCs combined with the complex frequency-shifted stretching function (CFS), we introduce a novel numerical implementation method for PML absorbing boundary conditions with simple calculation equations, small memory requirement, and easy programming. 展开更多
关键词 PML absorbing boundary condition non-splitting forward modeling
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Geo-engineered buffer capacity of two-layered absorbing system under the impact of rock avalanches based on Discrete Element Method 被引量:15
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作者 BI Yu-zhang HE Si-ming +5 位作者 LI Xin-po WU Yong XU Qiang OUYANG Chao-jun SU Li-Jun WANG Hao 《Journal of Mountain Science》 SCIE CSCD 2016年第5期917-929,共13页
Many rock avalanches were triggered by the Wenchuan earthquake on May 12, 2008 in southwest China. Protection galleries covered with a single soil layer are usually used to protect against rockfall. Since one-layer pr... Many rock avalanches were triggered by the Wenchuan earthquake on May 12, 2008 in southwest China. Protection galleries covered with a single soil layer are usually used to protect against rockfall. Since one-layer protection galleries do not have sufficient buffer capacity, a two-layered absorbing system has been designed. This study aims to find whether an expanded poly-styrol (EPS) cushion, which is used in the soil-covered protection galleries for shock absorption, could be positioned under dynamic loadings. The dynamic impacts of the two-layered absorbing system under the conditions of rock avalanches are numerically simulated through a 2D discrete dement method. By selecting reasonable parameters, a series of numerical experiments were conducted to find the best combination for the two- layered absorbing system. The values of the EPS layer area as a percentage of the total area were set as 0% (Sl), 22~ (S2), and 70% ($3). 22~ of the area of the EPS layer was found to be a reasonable value, and experiments were conducted to find the best position of the EPS layer in the two-layered absorbing system. The numerical results yield useful conclusions regarding the interaction between the impacting avalanches and the two-layered absorbing system. The soil layer can absorb the shock energy effectively and S2 (0.4-m thick EPS cushion covered with soil layer) is the most efficient combination, which can reduce the impact force, compared with the other combinations. 展开更多
关键词 Discrete element method Buffer capacity Dynamic simulation Impact force Two-layered absorbing system
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Numerical Wave Channel with Absorbing Wave-Maker 被引量:16
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作者 Wang YongxueProfessor, State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024 《China Ocean Engineering》 SCIE EI 1995年第2期149-160,共12页
The numerical wave channel has been developed based on the volume of fluid method (VOF) in conjunction with the Navier-Stokes equations. The absorbing wave-maker boundary on the left side of the channel is presented b... The numerical wave channel has been developed based on the volume of fluid method (VOF) in conjunction with the Navier-Stokes equations. The absorbing wave-maker boundary on the left side of the channel is presented by prescribing velocity reference to linear wave-maker theory. The principle of which is that the numerical wave-maker is designed to move in a way that generates the required incident wave and cancels out any reflected wave that reach it at the same time. On the right side of the channel, the open boundary is set to permit incident waves to be transmitted freely. The parametric studies have been carried out at a range of ratios of water depth to wave length d/ L from 0.124 to 0.219, with wave height in the front of paddle/water depth ratio (H0 / d) from 0.1 to 0.3. Wave height, wave pressure distribution along the channel and velocity field are obtained for both open boundary condition and reflective boundary condition at the other end of the channel. For a reflective case, it is shown that the absorbing wave-maker is very effective in canceling out the reflected wave that reaches the numerical paddle and highly repeatable waves can be generated. 展开更多
关键词 numerical wave channel absorbing wave-maker VOF method
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Recent progress and future prospects of oil-absorbing materials 被引量:16
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作者 Tao Zhang Zhangdi Li +4 位作者 Yuanfei Lü Yu Liu Dongya Yang Qiurong Li Fengxian Qiu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第6期1282-1295,共14页
Oil and organic solvent contamination, derived from oil spills and organic solvent leakage, has been recognized as one of the major environmental issues imposing a serious threat to both human and ecosystem health. Am... Oil and organic solvent contamination, derived from oil spills and organic solvent leakage, has been recognized as one of the major environmental issues imposing a serious threat to both human and ecosystem health. Among the various presented technologies applied for oil/water separation, oil absorption process has been explored widely and offers satisfactory results especially with surface modified oil-absorbing material and/or hybrid absorbents. In this review, we summarize the recent research activities involved in the designing strategies of oil-absorbing absorbents and their application in oil absorption. Then, an extensive list of various oil-absorbing materials from literature, including polymer materials, porous inorganic materials and biomass materials, has been compiled and the oil adsorption capacities toward various types of oils and organic solvents as available in the literature are presented along with highlighting and discussing the various factors involved in the designing of oil-absorbing absorbents tested so far for oil/water separation. Finally, some future trends and perspectives in oil-absorbing material are outlined. 展开更多
关键词 Oil/water SEPARATION Oil-absorbing MATERIAL SUPERHYDROPHOBIC Hydrid absorbents
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Electromagnetic and microwave absorbing properties of FeCoB powder composites 被引量:7
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作者 Shen-Gen Zhang Hang-Xin Zhu +3 位作者 Jian-Jun Tian De-An Pan Bo Liu Yan-Tao Kang 《Rare Metals》 SCIE EI CAS CSCD 2013年第4期402-407,共6页
The electromagnetic and microwave absorbing properties of FeCoB powder composites prepared by sin- gle-roller melt-spinning and mechanical milling processes were investigated in this paper. The result indicates that t... The electromagnetic and microwave absorbing properties of FeCoB powder composites prepared by sin- gle-roller melt-spinning and mechanical milling processes were investigated in this paper. The result indicates that the flake-like powders are obtained. As milling time increases, the flake-like powder particles tend to agglomerate, causing the flake-like powders decrease gradually. The milling time plays an important role in the electromagnetic parameters which relates to the shape and size of the powder particles. The calculation shows that the sample milled for 6 h could achieve an optimal reflection loss of -11.5 dB at 5.8 GHz, with mass fraction of 83 % and a matching thickness of 1.8 mm. The result also indicates that the microwave absorbing properties of the FeCoB powder composites are adjustable by changing their thickness, and can be applied as a thinner microwave absorbing material in the range of 2-8 GHz. 展开更多
关键词 Fe48Co48B4 powder composites Mechanical milling Electromagnetic parameters Microwave absorbing properties
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Application of Nanocrystalline LaNi_5-type Hydrogen Absorbing Alloys in Ni-MH_x Batteries 被引量:5
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作者 Jurczyk M Nowak M 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第5期596-599,共4页
The structure and electrochemical properties of nanocrystalline LaNi_5-type alloys were studied. These materials were prepared by mechanical alloying (MA) followed by annealing. The properties of hydrogen host materia... The structure and electrochemical properties of nanocrystalline LaNi_5-type alloys were studied. These materials were prepared by mechanical alloying (MA) followed by annealing. The properties of hydrogen host materials can be modified substantially by alloying to obtain the desired storage characteristics. It was found that the partial substitution of Ni by Al or Mn in LaNi_(5-x)M_x alloy leads to an increase in discharge capacity. The alloying elements such as Al, Mn and Co greatly improved the cycle life of LaNi_5 material. For example, in the nanocrystalline LaNi_(3.75)Mn_(0.75)Al_(0.25)Co_(0.25) powder, discharge capacity up to 258 mAh·g^(-1) was measured (at 40 mA·g^(-1) discharge current). Furthermore, the effect of the graphite coating on the structure of some nanocrystalline alloys and the electrodes characteristics were investigated. The mechanical coating with graphite effectively reduced the degradation rate of the studied electrode materials. The combination of a nanocrystalline LaNi_5-type hydride electrodes and a nickel positive electrode to form a Ni-MH battery, was successful. 展开更多
关键词 hydrogen absorbing materials electrode materials nanocrystalline materials Ni-MH_x batteries rare earths
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