The resuspension of marine sediments plays a key role in the biogeochemical cycle and marine ecology system.Internal solitary waves are considered to be important driving forces of the resuspension of bottom sediments...The resuspension of marine sediments plays a key role in the biogeochemical cycle and marine ecology system.Internal solitary waves are considered to be important driving forces of the resuspension of bottom sediments.In this paper,the movement of turbidity currents,the generation and the effects on the bottom bed of internal solitary waves and excitation waves are studied by flume tests and numerical simulations,and the sediment resuspension are analyzed.The results show that the excitation wave can lead to the resuspension of the bottom sediments under all the conditions,while the internal solitary wave can lead to the resuspension of the sediment only under some special conditions,such as high amplitude or large underwater slope.Under the experimental conditions,the change in the near-bottom velocity caused by the excitation wave is close to three times that of the internal solitary wave.展开更多
The ion-acoustic(IA) mode exhibiting various orbital angular momentum(OAM) states is examined in a plasma with drifting electrons.The constituent plasma species are modeled with a non-gyrotropic Maxwellian distributio...The ion-acoustic(IA) mode exhibiting various orbital angular momentum(OAM) states is examined in a plasma with drifting electrons.The constituent plasma species are modeled with a non-gyrotropic Maxwellian distribution and discussion of dispersion relation and growth rate of twisted IA waves under various conditions is presented.In the domain of kinetic model,the twisted IA waves are characterized by Laguerre-Gaussian(LG) solutions,where plasma distribution function and electric field are decomposed into axial and azimuthal components.The plasma response function is obtained under paraxial approximations and investigated for threshold condition of instability growth rate with helical electric field structures.The impact of an extra electron specie on the instability is demonstrated through a comparison of twisted waves for single and double electron species.展开更多
Starting from an improved mapping approach and a linear variable separation approach, a new family of exact solutions (including solitary wave solutions, periodic wave solutions and rational function solutions) with...Starting from an improved mapping approach and a linear variable separation approach, a new family of exact solutions (including solitary wave solutions, periodic wave solutions and rational function solutions) with arbitrary functions for a general (2+1)-dimensional Korteweg de solutions, we obtain some novel dromion-lattice solitons, system Vries system (GKdV) is derived. According to the derived complex wave excitations and chaotic patterns for the GKdV展开更多
With the help of an improved mapping approach and a linear-variable-separation approach, a new family of exact solutions with arbitrary functions of the (2+1)-dimensional Nizhnik-Novikov-Veselov system (NNV) is d...With the help of an improved mapping approach and a linear-variable-separation approach, a new family of exact solutions with arbitrary functions of the (2+1)-dimensional Nizhnik-Novikov-Veselov system (NNV) is derived. Based on the derived solutions and using some multi-valued functions, we find a few new folded solitary wave excitations for the (2+1)-dimensional NNV system.展开更多
This paper reported a compact system of capacitively coupled contactless conductivity detection (C4D) based on the square wave excitation voltage for capillary electrophoresis, and it exhibited excellent sensitivity...This paper reported a compact system of capacitively coupled contactless conductivity detection (C4D) based on the square wave excitation voltage for capillary electrophoresis, and it exhibited excellent sensitivity at the optimal frequency of 198 kHz. The feasibility and sensitivity of this detector was demonstrated by simultaneous detection of thirteen ions including alkali, alkaline earth and heavy metal ions. And the detection limits (S/N 3) were in the range of 0.2-1μmol/L for Mn^2+, K^+, Na^+, Mg^2+, Ca^2+, Li^+, Ba^2+, and 7-25 μmol/L for Ni^2+, Cu^2+, Cd^2+, Pb^2+, Co^2+, Zn^2+.展开更多
We study rogue waves in an inhomogeneous nonlinear optical fiber with variable coefficients. An exact rogue wave solution that describes rogue wave excitation and modulation on a bright soliton pulse is obtained. Spec...We study rogue waves in an inhomogeneous nonlinear optical fiber with variable coefficients. An exact rogue wave solution that describes rogue wave excitation and modulation on a bright soliton pulse is obtained. Special properties of rogue waves on the bright soliton, such as the trajectory and spectrum, are analyzed in detail. In particular, our analytical results suggest a way of sustaining the peak shape of rogue waves on the soliton background by choosing an appropriate dispersion parameter.展开更多
Starting from an improved projective method and a linear variable separation approach, new families of variable separation solutions (including solltary wave solutlons, periodic wave solutions and rational function s...Starting from an improved projective method and a linear variable separation approach, new families of variable separation solutions (including solltary wave solutlons, periodic wave solutions and rational function solutions) with arbitrary functions [or the (2+ 1)-dimensional general/zed Broer-Kaup (GBK) system are derived. Usually, in terms of solitary wave solutions and/or rational function solutions, one can find abundant important localized excitations. However, based on the derived periodic wave solution in this paper, we reveal some complex wave excitations in the (2+1)-dimensional GBK system, which describe solitons moving on a periodic wave background. Some interesting evolutional properties for these solitary waves propagating on the periodic wave bactground are also briefly discussed.展开更多
The magnetization curves at 1.5 K and thermomagnetic curves for amorphous Fe_(90-x)Si_xZr_(10)(x=0,4,7 and 10)alloys prepared by the drum spinning technique have been measured with an extracting sample magnetometer.It...The magnetization curves at 1.5 K and thermomagnetic curves for amorphous Fe_(90-x)Si_xZr_(10)(x=0,4,7 and 10)alloys prepared by the drum spinning technique have been measured with an extracting sample magnetometer.It is obtained that the average magnetic moment,,per magnetic atom and Curie temperature,T_c,in the amorphous FeSiZr alloys increase with increasing Si content.The and T_c are found to be quite small,compared with amorphous FeSiB alloys.This unusual behavior is suggested to be due to the presence of the Fe—Fe antiferromagnetic interactions.The temperature dependence of magnetization at lower temperature is in accordance with Bloch's T^(3/2) law.Calculation shows that the spin wave stiffness constant,D,increases with increasing Si content from 0.37 meV·nm^2 for x=0 to 0.538 meV·nm^2 for x=10.The values of<r^2>indicate that the range of the exchange interaction is roughly the mean atomic distance of nearest neighbours.展开更多
In this paper we have given an analytic excitation solution of exploding wave in infinite elastic body with growing spherical inner boundary, and the convergence region of series in this solution determined. Some char...In this paper we have given an analytic excitation solution of exploding wave in infinite elastic body with growing spherical inner boundary, and the convergence region of series in this solution determined. Some characters of the displacement wave have also been discussed.展开更多
The dynamical behavior of fluids affected by the asymmetric gravity jitter oscillations, in particular, the effect of surface tension on partially-filled rotating fluids in a Dewar tank imposed by time-dependent direc...The dynamical behavior of fluids affected by the asymmetric gravity jitter oscillations, in particular, the effect of surface tension on partially-filled rotating fluids in a Dewar tank imposed by time-dependent directions of background reduced gravity accelerations is investigated. Results show that the greater the components of background reduced gravity in radial and circumferential directions, the greater will be the tendency toward increasing amplitude and degrees of asymmetry of the liquid-vapor interface profiles.展开更多
Starting from the extended mapping approach and a linear variable separation method, we find new families of variable separation solutions with some arbitrary functions for the (3+1)-dimensionM Burgers system. Then...Starting from the extended mapping approach and a linear variable separation method, we find new families of variable separation solutions with some arbitrary functions for the (3+1)-dimensionM Burgers system. Then based on the derived exact solutions, some novel and interesting localized coherent excitations such as embedded-solitons, taper-like soliton, complex wave excitations in the periodic wave background are revealed by introducing appropriate boundary conditions and/or initial qualifications. The evolutional properties of the complex wave excitations are briefly investigated.展开更多
Acoustic wave exhibits inherently different characters of propagation, excitation and coupling in phonon band-gap materials in which its elastic, piezoelectric constants are modulated in order of acoustic wavelength. ...Acoustic wave exhibits inherently different characters of propagation, excitation and coupling in phonon band-gap materials in which its elastic, piezoelectric constants are modulated in order of acoustic wavelength. These kinds of novel materials were exampled by phononic crystals with elastic constants modulation, acoustic superlattice and ionic-type phononic crystals with piezoelectric constants modulation. In this talk, phonic crystals were constructed with steel rods embedded in air. Negative refraction of acoustic wave was both experimentally and theoretically established in the phononic crystals. The propagation of acoustic wave in the crystals show acoustic band structures because the waves are strong scattered at the Brillouin Zone Boundaries, analogy to electron band structure in real crystals and photonic band structure in photonic crystals. In the acoustic superlattice, ultrasonic waves could be excited by applied alternative electric fields by piezoelectric effect. The frequency, mode and amplitude of the excited wave are determined by the microstructured parameters of the acoustic superlattice at the condition of phase matching. Ionic-type phononic crystals describe the coupling between superlattice phonon and electromagnetic wave. The coupling process resulted in the polariton with a dispersion relation totally different from that of both superlattice phonon and E-M waves, analogy to the polariton of the ionic crystals but in microwave instead of infrared light. These microstructural dielectric materials show artificial abnormal properties and will find novel application in ultrasonic devices and microwave devices.展开更多
The interaction between wave and horizontal and vertical plates is investigated by the boundary element method, and the relations of wave exciting force with plate thickness, submergence and length are obtained. It is...The interaction between wave and horizontal and vertical plates is investigated by the boundary element method, and the relations of wave exciting force with plate thickness, submergence and length are obtained. It is found that: 1) The efficient wave exciting force exists while plate submergence is less than 0.5 m, and the plate is very thin with order O(0.005 m). 2) The maximum heave wave exciting force exists, and it is the main factor for surface and submerged horizontal plate while the roll force can be ignored. 3) The maximum sway wave exciting force exists, it is the main factor for surface or submerged vertical plate, and the roll force is about 20 times of horizontal plate.展开更多
Shallow water waves and a host of long wave phenomena are commonly investigated by various models of nonlinear evolution equations. Examples include the Korteweg-de Vries, the Camassa-Holm, and the Whitham-Broer-Kaup ...Shallow water waves and a host of long wave phenomena are commonly investigated by various models of nonlinear evolution equations. Examples include the Korteweg-de Vries, the Camassa-Holm, and the Whitham-Broer-Kaup (WBK) equations. Here a generalized WBK system is studied via the multi-linear variable separation approach. A special class of wave profiles with discontinuous derivatives ("peakons") is developed. Peakons of various features, e.g. periodic, pulsating or fractal, are investigated and interactions of such entities are studied.展开更多
This paper deals. with the problem of dynamic response of platform-cylinder group foumdation. Dynamic interaction of cylinder group foudation-water-soil is taken into account and the analysis of dynamic response to ex...This paper deals. with the problem of dynamic response of platform-cylinder group foumdation. Dynamic interaction of cylinder group foudation-water-soil is taken into account and the analysis of dynamic response to excitation of water wave force is given by analytic method ..The numerical examples are presented and the influence of systent’s parameters on the dynamic behaviour is discussed.展开更多
The long-distance movement of turbidity currents in submarine canyons can transport large amounts of sediment to deep-sea plains.Previous studies show obvious differences in the turbidity current velocities derived fr...The long-distance movement of turbidity currents in submarine canyons can transport large amounts of sediment to deep-sea plains.Previous studies show obvious differences in the turbidity current velocities derived from the multiple cables damage events ranging from 5.9 to 28.0 m/s and those of field observations between 0.15 and 7.2 m/s.Therefore,questions remain regarding whether a turbid fluid in an undersea environment can flow through a submarine canyon for a long distance at a high speed.A new model based on weakly stable sediment is proposed(proposed failure propagation model for weakly stable sediments,WS S-PFP model for short)to explain the high-speed and long-range motion of turbidity currents in submarine canyons through the combination of laboratory tests and numerical analogs.The model is based on two mechanisms:1)the original turbidity current triggers the destabilization of the weakly stable sediment bed and promotes the destabilization and transport of the soft sediment in the downstream direction and 2)the excitation wave that forms when the original turbidity current moves into the canyon leads to the destabilization and transport of the weakly stable sediment in the downstream direction.The proposed model will provide dynamic process interpretation for the study of deep-sea deposition,pollutant transport,and optical cable damage.展开更多
An excited experiment system of 20# steel pipe was established with oil cylinder, 20# steel pipe, frequency converter, pump station and wave exciter generating unsteady flow artificially. The experimental results show...An excited experiment system of 20# steel pipe was established with oil cylinder, 20# steel pipe, frequency converter, pump station and wave exciter generating unsteady flow artificially. The experimental results showed that the 20# steel pipe could vibrate with the excitation of unsteady flows, and the vibration was periodic, instead of a harmonic one. Particles on the front and rear positions of pipe vibrated synchronously, and the vibration intensity of the pipe's two ends was greater than in the middle. System pressure and wave exciter's frequency had much influence upon pipe's amplitude. Pipe's vibration frequency was little affected by system pressure, and its value was close to the wave exciter's. Therefore, the active control of pipe's vibration can be realized by setting system pressure and adjusting frequency converter's frequency.展开更多
By applying the integral transform method and the inverse transformation technique based upon the two types of integration, the present paper has successfully obtained an exact algebraic solution for a two-dimensional...By applying the integral transform method and the inverse transformation technique based upon the two types of integration, the present paper has successfully obtained an exact algebraic solution for a two-dimensional Lamb's problem due to a strip impulse loading for the first time. With the algebraic result, the excitation and propagation processes of stress waves, including the longitudinal wave, the transverse wave, and Rayleigh-wave, are discussed in detail. A few new conclusions have been drawn from currently available integral results or computational results.展开更多
The radiation and the diffraction of linear waves by a rectangular structure with an opening at its bottom floating in oblique seas of finite depth are investigated. Analytical expressions for the radiated potentials ...The radiation and the diffraction of linear waves by a rectangular structure with an opening at its bottom floating in oblique seas of finite depth are investigated. Analytical expressions for the radiated potentials and the diffracted potential are obtained by use of the method of separation of variables and the eigenfunction expansion method, with the unknown coefficients being determined by the boundary conditions and the matching requirement on the interface. The hydrodynamic coefficients and the wave excitation forces are verified using the symmetry properties of coupled hydrodynamic coefficients and one specific example investigated previously. By use of the present analytical-numerical solution, the influences of the angle of incidence, the width of the opening on the wave forces and the hydrodynamic coefficients are investigated. It is also found that in the oblique sea the external excitation frequency that can lead to the resonance of a rectangular tank depends on the wave direction and the wave number of the incident wave.展开更多
A 3-D time-domain seakeeping analysis tool has been newly developed by using a higher-order boundary element method with the Rankine source as the kernel function. An iterative time-marching scheme for updating both k...A 3-D time-domain seakeeping analysis tool has been newly developed by using a higher-order boundary element method with the Rankine source as the kernel function. An iterative time-marching scheme for updating both kinematic and dynamic free-surface boundary conditions is adopted for achieving numerical accuracy and stability. A rectangular computational domain moving with the mean speed of ship is introduced. A damping beach at the outer portion of the truncated free surface is installed for satisfying the radiation condition. After numerical convergence checked, the diffraction unsteady problem of a Wigley hull traveling with a constant forward speed in waves is studied. Extensive results including wave exciting forces, wave patterns and pressure distributions on the hull are presented to validate the efficiency and accuracy of the proposed 3-D time-domain iterative Rankine BEM approach. Computed results are compared to be in good agreement with the corresponding experimental data and other published numerical solutions.展开更多
基金The research was supported by the National Natural Science Foundation of China(Nos.42206055,41976049,41720104001)the Taishan Scholar Project of Shandong Province(No.TS20190913)the Fundamental Research Funds for the Central Universities(No.202061028).
文摘The resuspension of marine sediments plays a key role in the biogeochemical cycle and marine ecology system.Internal solitary waves are considered to be important driving forces of the resuspension of bottom sediments.In this paper,the movement of turbidity currents,the generation and the effects on the bottom bed of internal solitary waves and excitation waves are studied by flume tests and numerical simulations,and the sediment resuspension are analyzed.The results show that the excitation wave can lead to the resuspension of the bottom sediments under all the conditions,while the internal solitary wave can lead to the resuspension of the sediment only under some special conditions,such as high amplitude or large underwater slope.Under the experimental conditions,the change in the near-bottom velocity caused by the excitation wave is close to three times that of the internal solitary wave.
文摘The ion-acoustic(IA) mode exhibiting various orbital angular momentum(OAM) states is examined in a plasma with drifting electrons.The constituent plasma species are modeled with a non-gyrotropic Maxwellian distribution and discussion of dispersion relation and growth rate of twisted IA waves under various conditions is presented.In the domain of kinetic model,the twisted IA waves are characterized by Laguerre-Gaussian(LG) solutions,where plasma distribution function and electric field are decomposed into axial and azimuthal components.The plasma response function is obtained under paraxial approximations and investigated for threshold condition of instability growth rate with helical electric field structures.The impact of an extra electron specie on the instability is demonstrated through a comparison of twisted waves for single and double electron species.
基金Project supported by the National Natural Science Foundation of China (Grant No 10172056), the Natural Science Foundation of Zhejiang Province, China (Grant No Y604106), the Foundation of New Century 151 Talent Engineering of Zhejiang Province, the Scientific Research Foundation of Zhejiang Provincial Education Department of China (Grant No 20070568) and the Natural Science Foundation of Zhejiang Lishui University (Grant No KZ04008).
文摘Starting from an improved mapping approach and a linear variable separation approach, a new family of exact solutions (including solitary wave solutions, periodic wave solutions and rational function solutions) with arbitrary functions for a general (2+1)-dimensional Korteweg de solutions, we obtain some novel dromion-lattice solitons, system Vries system (GKdV) is derived. According to the derived complex wave excitations and chaotic patterns for the GKdV
基金supported by the Natural Science Foundation of Zhejiang Province under Grant No.Y604106the Scientific Research Foundation of Zhejiang Provincial Education Department under Grant No.20070568the Natural Science Foundation of Zhejiang Lishui University under Grant No.KZ08001
文摘With the help of an improved mapping approach and a linear-variable-separation approach, a new family of exact solutions with arbitrary functions of the (2+1)-dimensional Nizhnik-Novikov-Veselov system (NNV) is derived. Based on the derived solutions and using some multi-valued functions, we find a few new folded solitary wave excitations for the (2+1)-dimensional NNV system.
基金support from the National Natural Science Foundation of China(No.20475018)the Key Program of Guangdong Natural Science Foundation(No.05103552)
文摘This paper reported a compact system of capacitively coupled contactless conductivity detection (C4D) based on the square wave excitation voltage for capillary electrophoresis, and it exhibited excellent sensitivity at the optimal frequency of 198 kHz. The feasibility and sensitivity of this detector was demonstrated by simultaneous detection of thirteen ions including alkali, alkaline earth and heavy metal ions. And the detection limits (S/N 3) were in the range of 0.2-1μmol/L for Mn^2+, K^+, Na^+, Mg^2+, Ca^2+, Li^+, Ba^2+, and 7-25 μmol/L for Ni^2+, Cu^2+, Cd^2+, Pb^2+, Co^2+, Zn^2+.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11475135 and 11547302the Doctoral Program Funds of the Ministry of Education of China under Grant No 20126101110004
文摘We study rogue waves in an inhomogeneous nonlinear optical fiber with variable coefficients. An exact rogue wave solution that describes rogue wave excitation and modulation on a bright soliton pulse is obtained. Special properties of rogue waves on the bright soliton, such as the trajectory and spectrum, are analyzed in detail. In particular, our analytical results suggest a way of sustaining the peak shape of rogue waves on the soliton background by choosing an appropriate dispersion parameter.
基金The project supported by the Natural Science Foundation of Zhejiang Province under Grant Nos. Y604106 and Y606181, the Foundation of New Century "151 Talent Engineering" of Zhejiang Province, the Scientific Research Foundation of Key Discipline of Zhejiang Province, and the Natural Science Foundation of Zhejiang Lishui University under Grant No. KZ05005 Acknowledgments The authors are in debt to Profs. J.P. Fang, H.P. Zhu, and J.F. Zhang, and Drs. Z.Y. Ma and W.H. Huang for their fruitful discussions.
文摘Starting from an improved projective method and a linear variable separation approach, new families of variable separation solutions (including solltary wave solutlons, periodic wave solutions and rational function solutions) with arbitrary functions [or the (2+ 1)-dimensional general/zed Broer-Kaup (GBK) system are derived. Usually, in terms of solitary wave solutions and/or rational function solutions, one can find abundant important localized excitations. However, based on the derived periodic wave solution in this paper, we reveal some complex wave excitations in the (2+1)-dimensional GBK system, which describe solitons moving on a periodic wave background. Some interesting evolutional properties for these solitary waves propagating on the periodic wave bactground are also briefly discussed.
文摘The magnetization curves at 1.5 K and thermomagnetic curves for amorphous Fe_(90-x)Si_xZr_(10)(x=0,4,7 and 10)alloys prepared by the drum spinning technique have been measured with an extracting sample magnetometer.It is obtained that the average magnetic moment,,per magnetic atom and Curie temperature,T_c,in the amorphous FeSiZr alloys increase with increasing Si content.The and T_c are found to be quite small,compared with amorphous FeSiB alloys.This unusual behavior is suggested to be due to the presence of the Fe—Fe antiferromagnetic interactions.The temperature dependence of magnetization at lower temperature is in accordance with Bloch's T^(3/2) law.Calculation shows that the spin wave stiffness constant,D,increases with increasing Si content from 0.37 meV·nm^2 for x=0 to 0.538 meV·nm^2 for x=10.The values of<r^2>indicate that the range of the exchange interaction is roughly the mean atomic distance of nearest neighbours.
文摘In this paper we have given an analytic excitation solution of exploding wave in infinite elastic body with growing spherical inner boundary, and the convergence region of series in this solution determined. Some characters of the displacement wave have also been discussed.
文摘The dynamical behavior of fluids affected by the asymmetric gravity jitter oscillations, in particular, the effect of surface tension on partially-filled rotating fluids in a Dewar tank imposed by time-dependent directions of background reduced gravity accelerations is investigated. Results show that the greater the components of background reduced gravity in radial and circumferential directions, the greater will be the tendency toward increasing amplitude and degrees of asymmetry of the liquid-vapor interface profiles.
基金the Natural Science Foundation of Zhejiang Province under Grant Nos.Y604106 and Y606181the Foundation of New Century"151 Talent Engineering"of Zhejiang Provincethe Scientific Research Foundation of Key Discipline of Zhejiang Province
文摘Starting from the extended mapping approach and a linear variable separation method, we find new families of variable separation solutions with some arbitrary functions for the (3+1)-dimensionM Burgers system. Then based on the derived exact solutions, some novel and interesting localized coherent excitations such as embedded-solitons, taper-like soliton, complex wave excitations in the periodic wave background are revealed by introducing appropriate boundary conditions and/or initial qualifications. The evolutional properties of the complex wave excitations are briefly investigated.
文摘Acoustic wave exhibits inherently different characters of propagation, excitation and coupling in phonon band-gap materials in which its elastic, piezoelectric constants are modulated in order of acoustic wavelength. These kinds of novel materials were exampled by phononic crystals with elastic constants modulation, acoustic superlattice and ionic-type phononic crystals with piezoelectric constants modulation. In this talk, phonic crystals were constructed with steel rods embedded in air. Negative refraction of acoustic wave was both experimentally and theoretically established in the phononic crystals. The propagation of acoustic wave in the crystals show acoustic band structures because the waves are strong scattered at the Brillouin Zone Boundaries, analogy to electron band structure in real crystals and photonic band structure in photonic crystals. In the acoustic superlattice, ultrasonic waves could be excited by applied alternative electric fields by piezoelectric effect. The frequency, mode and amplitude of the excited wave are determined by the microstructured parameters of the acoustic superlattice at the condition of phase matching. Ionic-type phononic crystals describe the coupling between superlattice phonon and electromagnetic wave. The coupling process resulted in the polariton with a dispersion relation totally different from that of both superlattice phonon and E-M waves, analogy to the polariton of the ionic crystals but in microwave instead of infrared light. These microstructural dielectric materials show artificial abnormal properties and will find novel application in ultrasonic devices and microwave devices.
基金supported by Foundation of Science and Technology of Dalian (Grant No. 2008A16GX248)
文摘The interaction between wave and horizontal and vertical plates is investigated by the boundary element method, and the relations of wave exciting force with plate thickness, submergence and length are obtained. It is found that: 1) The efficient wave exciting force exists while plate submergence is less than 0.5 m, and the plate is very thin with order O(0.005 m). 2) The maximum heave wave exciting force exists, and it is the main factor for surface and submerged horizontal plate while the roll force can be ignored. 3) The maximum sway wave exciting force exists, it is the main factor for surface or submerged vertical plate, and the roll force is about 20 times of horizontal plate.
基金the National Natural Science Foundation of China (10475055,10547124 and 90503006)the Hong Kong Research Grant Council Contract HKU 7123/05E.
文摘Shallow water waves and a host of long wave phenomena are commonly investigated by various models of nonlinear evolution equations. Examples include the Korteweg-de Vries, the Camassa-Holm, and the Whitham-Broer-Kaup (WBK) equations. Here a generalized WBK system is studied via the multi-linear variable separation approach. A special class of wave profiles with discontinuous derivatives ("peakons") is developed. Peakons of various features, e.g. periodic, pulsating or fractal, are investigated and interactions of such entities are studied.
文摘This paper deals. with the problem of dynamic response of platform-cylinder group foumdation. Dynamic interaction of cylinder group foudation-water-soil is taken into account and the analysis of dynamic response to excitation of water wave force is given by analytic method ..The numerical examples are presented and the influence of systent’s parameters on the dynamic behaviour is discussed.
基金Supported by the National Natural Science Foundation of China(Nos.42206055,41976049)the Taishan Scholar Project of Shandong Province(No.TS20190913)the Fundamental Research Funds for the Central Universities(No.202061028)。
文摘The long-distance movement of turbidity currents in submarine canyons can transport large amounts of sediment to deep-sea plains.Previous studies show obvious differences in the turbidity current velocities derived from the multiple cables damage events ranging from 5.9 to 28.0 m/s and those of field observations between 0.15 and 7.2 m/s.Therefore,questions remain regarding whether a turbid fluid in an undersea environment can flow through a submarine canyon for a long distance at a high speed.A new model based on weakly stable sediment is proposed(proposed failure propagation model for weakly stable sediments,WS S-PFP model for short)to explain the high-speed and long-range motion of turbidity currents in submarine canyons through the combination of laboratory tests and numerical analogs.The model is based on two mechanisms:1)the original turbidity current triggers the destabilization of the weakly stable sediment bed and promotes the destabilization and transport of the soft sediment in the downstream direction and 2)the excitation wave that forms when the original turbidity current moves into the canyon leads to the destabilization and transport of the weakly stable sediment in the downstream direction.The proposed model will provide dynamic process interpretation for the study of deep-sea deposition,pollutant transport,and optical cable damage.
基金Funded by the National Natural Science Foundation of China(No. 50775154)the Natural Science Foundation for Young Scientists of Shanxi Province(No. 2010201025)
文摘An excited experiment system of 20# steel pipe was established with oil cylinder, 20# steel pipe, frequency converter, pump station and wave exciter generating unsteady flow artificially. The experimental results showed that the 20# steel pipe could vibrate with the excitation of unsteady flows, and the vibration was periodic, instead of a harmonic one. Particles on the front and rear positions of pipe vibrated synchronously, and the vibration intensity of the pipe's two ends was greater than in the middle. System pressure and wave exciter's frequency had much influence upon pipe's amplitude. Pipe's vibration frequency was little affected by system pressure, and its value was close to the wave exciter's. Therefore, the active control of pipe's vibration can be realized by setting system pressure and adjusting frequency converter's frequency.
基金Project supported by the National Natural Science Foundation of China(No.10572002).
文摘By applying the integral transform method and the inverse transformation technique based upon the two types of integration, the present paper has successfully obtained an exact algebraic solution for a two-dimensional Lamb's problem due to a strip impulse loading for the first time. With the algebraic result, the excitation and propagation processes of stress waves, including the longitudinal wave, the transverse wave, and Rayleigh-wave, are discussed in detail. A few new conclusions have been drawn from currently available integral results or computational results.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51679132,51079082)the Science and Technology Commission of Shanghai Municipality(Grant No.17040501600)
文摘The radiation and the diffraction of linear waves by a rectangular structure with an opening at its bottom floating in oblique seas of finite depth are investigated. Analytical expressions for the radiated potentials and the diffracted potential are obtained by use of the method of separation of variables and the eigenfunction expansion method, with the unknown coefficients being determined by the boundary conditions and the matching requirement on the interface. The hydrodynamic coefficients and the wave excitation forces are verified using the symmetry properties of coupled hydrodynamic coefficients and one specific example investigated previously. By use of the present analytical-numerical solution, the influences of the angle of incidence, the width of the opening on the wave forces and the hydrodynamic coefficients are investigated. It is also found that in the oblique sea the external excitation frequency that can lead to the resonance of a rectangular tank depends on the wave direction and the wave number of the incident wave.
基金supported by the Fundamental Research Developing Association for Shipbuilding and Offshore (REDAS), Japan
文摘A 3-D time-domain seakeeping analysis tool has been newly developed by using a higher-order boundary element method with the Rankine source as the kernel function. An iterative time-marching scheme for updating both kinematic and dynamic free-surface boundary conditions is adopted for achieving numerical accuracy and stability. A rectangular computational domain moving with the mean speed of ship is introduced. A damping beach at the outer portion of the truncated free surface is installed for satisfying the radiation condition. After numerical convergence checked, the diffraction unsteady problem of a Wigley hull traveling with a constant forward speed in waves is studied. Extensive results including wave exciting forces, wave patterns and pressure distributions on the hull are presented to validate the efficiency and accuracy of the proposed 3-D time-domain iterative Rankine BEM approach. Computed results are compared to be in good agreement with the corresponding experimental data and other published numerical solutions.