The motion of the self-gravitational gaseous stars can be described by the Euler-Poisson equations. The main purpose of this paper is concerned with the existence of stationary solutions of Euler-Poisson equations for...The motion of the self-gravitational gaseous stars can be described by the Euler-Poisson equations. The main purpose of this paper is concerned with the existence of stationary solutions of Euler-Poisson equations for some velocity fields and entropy functions that solve the conservation of mass and energy. Under different restriction to the strength of velocity field, we get the existence and multiplicity of the stationary solutions of Euler-Poisson system.展开更多
In this paper, the uniqueness of stationary solutions with vacuum of Euler-Poisson equations is considered. Through a nonlinear transformation which is a function of density and entropy, the corresponding problem can ...In this paper, the uniqueness of stationary solutions with vacuum of Euler-Poisson equations is considered. Through a nonlinear transformation which is a function of density and entropy, the corresponding problem can be reduced to a semilinear elliptic equation with a nonlinear source term consisting of a power function, for which the classical theory of the elliptic equations leads the authors to the uniqueness result under some assumptions on the entropy function S(x). As an example, the authors get the uniqueness of stationary solutions with vacuum of Euler-Poisson equations for S(x) =|x|θandθ∈{0}∪[2(N-2),+∞).展开更多
This paper is concerned with the system of Euler-Poisson equations as a model to describe the motion of the self-induced gravitational gaseous stars. When ~ 〈 7 〈 2, under the weak smoothness of entropy function, we...This paper is concerned with the system of Euler-Poisson equations as a model to describe the motion of the self-induced gravitational gaseous stars. When ~ 〈 7 〈 2, under the weak smoothness of entropy function, we find a sufficient condition to guarantee the existence of stationary solutions for some velocity fields and entropy function that solve the conservation of mass and energy.展开更多
In this article, the authors study the structure of the solutions for the EuierPoisson equations in a bounded domain of Rn with the given angular velocity and n is an odd number. For a ball domain and a constant angul...In this article, the authors study the structure of the solutions for the EuierPoisson equations in a bounded domain of Rn with the given angular velocity and n is an odd number. For a ball domain and a constant angular velocity, both existence and nonexistence theorem are obtained depending on the adiabatic gas constant 7. In addition, they obtain the monotonicity of the radius of the star with both angular velocity and center density. They also prove that the radius of a rotating spherically symmetric star, with given constant angular velocity and constant entropy, is uniformly bounded independent of the central density. This is different to the case of the non-rotating star.展开更多
This paper considers interfacial waves propagating along the interface between a two-dimensional two-fluid with a flat bottom and a rigid upper boundary. There is a light fluid layer overlying a heavier one in the sys...This paper considers interfacial waves propagating along the interface between a two-dimensional two-fluid with a flat bottom and a rigid upper boundary. There is a light fluid layer overlying a heavier one in the system, and a small density difference exists between the two layers. It just focuses on the weakly non-linear small amplitude waves by introducing two small independent parameters: the nonlinearity ratio ε, represented by the ratio of amplitude to depth, and the dispersion ratio μ, represented by the square of the ratio of depth to wave length, which quantify the relative importance of nonlinearity and dispersion. It derives an extended KdV equation of the interfacial waves using the method adopted by Dullin et al in the study of the surface waves when considering the order up to O(μ^2). As expected, the equation derived from the present work includes, as special cases, those obtained by Dullin et al for surface waves when the surface tension is neglected. The equation derived using an alternative method here is the same as the equation presented by Choi and Camassa. Also it solves the equation by borrowing the method presented by Marchant used for surface waves, and obtains its asymptotic solitary wave solutions when the weakly nonlinear and weakly dispersive terms are balanced in the extended KdV equation.展开更多
Global in time weak solutions to the α-model regularization for the three dimensional Euler-Poisson equations are considered in this paper. We prove the existence of global weak solutions to α-model regularization f...Global in time weak solutions to the α-model regularization for the three dimensional Euler-Poisson equations are considered in this paper. We prove the existence of global weak solutions to α-model regularization for the three dimension compressible EulerPoisson equations by using the Fadeo-Galerkin method and the compactness arguments on the condition that the adiabatic constant satisfies γ >4/3.展开更多
The nonlinear Schr?dinger(NLS for short)equation plays an important role in describing slow modulations in time and space of an underlying spatially and temporarily oscillating wave packet.In this paper,the authors st...The nonlinear Schr?dinger(NLS for short)equation plays an important role in describing slow modulations in time and space of an underlying spatially and temporarily oscillating wave packet.In this paper,the authors study the NLS approximation by providing rigorous error estimates in Sobolev spaces for the electron Euler-Poisson equation,an important model to describe Langmuir waves in a plasma.They derive an approximate wave packet-like solution to the evolution equations by the multiscale analysis,then they construct the modified energy functional based on the quadratic terms and use the rotating coordinate transform to obtain uniform estimates of the error between the true and approximate solutions.展开更多
We discuss structure-preserving numerical discretizations for repulsive and attractive Euler-Poisson equations that find applications in fluid-plasma and selfgravitation modeling.The scheme is fully discrete and struc...We discuss structure-preserving numerical discretizations for repulsive and attractive Euler-Poisson equations that find applications in fluid-plasma and selfgravitation modeling.The scheme is fully discrete and structure preserving in the sense that it maintains a discrete energy law,as well as hyperbolic invariant domain properties,such as positivity of the density and a minimum principle of the specific entropy.A detailed discussion of algorithmic details is given,as well as proofs of the claimed properties.We present computational experiments corroborating our analytical findings and demonstrating the computational capabilities of the scheme.展开更多
In this paper, we are concerned with the global existence of smooth solutions for the one dimen- sional relativistic Euler-Poisson equations: Combining certain physical background, the relativistic Euler-Poisson mode...In this paper, we are concerned with the global existence of smooth solutions for the one dimen- sional relativistic Euler-Poisson equations: Combining certain physical background, the relativistic Euler-Poisson model is derived mathematically. By using an invariant of Lax's method, we will give a sufficient condition for the existence of a global smooth solution to the one-dimensional Euler-Poisson equations with repulsive force.展开更多
In this study,a stable and robust interface-capturing method is developed to resolve inviscid,compressible two-fluid flows with general equation of state(EOS).The governing equations consist of mass conservation equat...In this study,a stable and robust interface-capturing method is developed to resolve inviscid,compressible two-fluid flows with general equation of state(EOS).The governing equations consist of mass conservation equation for each fluid,momentum and energy equations for mixture and an advection equation for volume fraction of one fluid component.Assumption of pressure equilibrium across an interface is used to close the model system.MUSCL-Hancock scheme is extended to construct input states for Riemann problems,whose solutions are calculated using generalized HLLC approximate Riemann solver.Adaptive mesh refinement(AMR)capability is built into hydrodynamic code.The resulting method has some advantages.First,it is very stable and robust,as the advection equation is handled properly.Second,general equation of state can model more materials than simple EOSs such as ideal and stiffened gas EOSs for example.In addition,AMR enables us to properly resolve flow features at disparate scales.Finally,this method is quite simple,time-efficient and easy to implement.展开更多
A one-dimensional quantum hydrodynamic model (or quantum Euler-Poisson system) for semiconductors with initial boundary conditions is considered for general pressure-density function. The existence and uniqueness of...A one-dimensional quantum hydrodynamic model (or quantum Euler-Poisson system) for semiconductors with initial boundary conditions is considered for general pressure-density function. The existence and uniqueness of the classical solution of the corresponding steady-state quantum hydrodynamic equations is proved. Furthermore, the global existence of classical solution, when the initial datum is a perturbation of t he steadystate solution, is obtained. This solution tends to the corresponding steady-state solution exponentially fast as the time tends to infinity.展开更多
The motion of the self-gravitational gaseous stars can be described by the Euler-Poisson equations. The main purpose of this article is concerned with the nonlinear stability of gaseous stars in the non-isentropic cas...The motion of the self-gravitational gaseous stars can be described by the Euler-Poisson equations. The main purpose of this article is concerned with the nonlinear stability of gaseous stars in the non-isentropic case, when 34 γ2, S(x,t) is a smooth bounded function. First, we verify that the steady states are minimizers of the energy via concentration-compactness method; then using the variational approach we obtain the stability results of the non-isentropic flow.展开更多
1 Fundamental Equations of Two-fluid Model The complicated debris flow is simplified as two-fluid model of solid and liquid two-phase flow,of which the liquid phase is slurry with the fine particle and the solid phase...1 Fundamental Equations of Two-fluid Model The complicated debris flow is simplified as two-fluid model of solid and liquid two-phase flow,of which the liquid phase is slurry with the fine particle and the solid phase is the coarse particle separated from slurry.The movement of each phase may be described by using a group of equations.The interaction of the two phases is cou-展开更多
The quasi-neutral limit of the multi-dimensional non-isentropic bipolar Euler-Poisson system is considered in the present paper. It is shown that for well-prepared initial data the smooth solution of the non-isentropi...The quasi-neutral limit of the multi-dimensional non-isentropic bipolar Euler-Poisson system is considered in the present paper. It is shown that for well-prepared initial data the smooth solution of the non-isentropic bipolar Euler-Poisson system converges strongly to the compressible non-isentropic Euler equations as the Debye length goes to zero.展开更多
Using the two-fluid Tolman-Oppenheimer-Volkoff equation,the properties of dark matter(DM)admixed neutron stars(DANSs)have been investigated.In contrast to previous studies,we find that an increase in the maximum mass ...Using the two-fluid Tolman-Oppenheimer-Volkoff equation,the properties of dark matter(DM)admixed neutron stars(DANSs)have been investigated.In contrast to previous studies,we find that an increase in the maximum mass and a decrease in the radius of 1.4 M_(⊙)NSs can occur simultaneously in DANSs.This stems from the ability of the equation of state(EOS)for DM to be very soft at low density but very stiff at high density.It is well known that the IU-FSU and XS models are unable to produce a neutron star(NS)with a maximum mass greater than 2.0 M_(⊙).However,by considering the IU-FSU and XS models for DANSs,there are interactions with DM that can produce a maximum mass greater than 2.0 M_(⊙)and a radius of 1.4 M_(⊙)NSs below 13.7 km.When considering a DANS,the difference between DM with chiral symmetry(DMC)and DM with meson exchange(DMM)becomes obvious when the central energy density of DM is greater than that of nuclear matter(NM).In this case,the DMC model with a DM mass of 1000 MeV can still produce a maximum mass greater than 2.0 M_(⊙)and a radius of a 1.4 M_(⊙)NS below 13.7 km.Additionally,although the maximum mass of the DANS using the DMM model is greater than 2.0 M_(⊙),the radius of a 1.4 M_(⊙)NS can surpass 13.7 km.In the two-fluid system,the maximum mass of a DANS can be larger than 3.0 M_(⊙).Consequently,the dimensionless tidal deformabilityΛCP of a DANS with 1.4 M_(⊙),which increases with increasing maximum mass,may be larger than 800 when the radius of the 1.4 M_(⊙)DANS is approximately 13.0 km.展开更多
We present a new numerical method to approximate the solutions of an Euler-Poisson model,which is inherent to astrophysical flows where gravity plays an important role.We propose a discretization of gravity which ensu...We present a new numerical method to approximate the solutions of an Euler-Poisson model,which is inherent to astrophysical flows where gravity plays an important role.We propose a discretization of gravity which ensures adequate coupling of the Poisson and Euler equations,paying particular attention to the gravity source term involved in the latter equations.In order to approximate this source term,its discretization is introduced into the approximate Riemann solver used for the Euler equations.A relaxation scheme is involved and its robustness is established.The method has been implemented in the software HERACLES[29]and several numerical experiments involving gravitational flows for astrophysics highlight the scheme.展开更多
The boundary plasma turbulence code BOUT models tokamak boundaryplasma turbulence in a realistic divertor geometry usingmodified Braginskii equations for plasma vorticity,density(ni),electron and ion temperature(Te,Ti...The boundary plasma turbulence code BOUT models tokamak boundaryplasma turbulence in a realistic divertor geometry usingmodified Braginskii equations for plasma vorticity,density(ni),electron and ion temperature(Te,Ti)and parallelmomenta.The BOUT code solves for the plasma fluid equations in a three dimensional(3D)toroidal segment(or a toroidal wedge),including the region somewhat inside the separatrix and extending into the scrape-off layer;the private flux region is also included.In this paper,a description is given of the sophisticated physical models,innovative numerical algorithms,and modern software design used to simulate edgeplasmas in magnetic fusion energy devices.The BOUT code’s unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.展开更多
基金supported by NSFC (10631030, 11071094)the fund of CCNU for Ph.D students (2009021)
文摘The motion of the self-gravitational gaseous stars can be described by the Euler-Poisson equations. The main purpose of this paper is concerned with the existence of stationary solutions of Euler-Poisson equations for some velocity fields and entropy functions that solve the conservation of mass and energy. Under different restriction to the strength of velocity field, we get the existence and multiplicity of the stationary solutions of Euler-Poisson system.
基金the Natural Science Foundation of China and the Excellent Teachers Foundation of Ministry of Education of China.
文摘In this paper, the uniqueness of stationary solutions with vacuum of Euler-Poisson equations is considered. Through a nonlinear transformation which is a function of density and entropy, the corresponding problem can be reduced to a semilinear elliptic equation with a nonlinear source term consisting of a power function, for which the classical theory of the elliptic equations leads the authors to the uniqueness result under some assumptions on the entropy function S(x). As an example, the authors get the uniqueness of stationary solutions with vacuum of Euler-Poisson equations for S(x) =|x|θandθ∈{0}∪[2(N-2),+∞).
基金supported by the Fundamental Research Funds for the Central Universities(2011-1a-021)
文摘This paper is concerned with the system of Euler-Poisson equations as a model to describe the motion of the self-induced gravitational gaseous stars. When ~ 〈 7 〈 2, under the weak smoothness of entropy function, we find a sufficient condition to guarantee the existence of stationary solutions for some velocity fields and entropy function that solve the conservation of mass and energy.
基金supported by the Natural Science Foundation of China (10471052,10631030)
文摘In this article, the authors study the structure of the solutions for the EuierPoisson equations in a bounded domain of Rn with the given angular velocity and n is an odd number. For a ball domain and a constant angular velocity, both existence and nonexistence theorem are obtained depending on the adiabatic gas constant 7. In addition, they obtain the monotonicity of the radius of the star with both angular velocity and center density. They also prove that the radius of a rotating spherically symmetric star, with given constant angular velocity and constant entropy, is uniformly bounded independent of the central density. This is different to the case of the non-rotating star.
文摘This paper considers interfacial waves propagating along the interface between a two-dimensional two-fluid with a flat bottom and a rigid upper boundary. There is a light fluid layer overlying a heavier one in the system, and a small density difference exists between the two layers. It just focuses on the weakly non-linear small amplitude waves by introducing two small independent parameters: the nonlinearity ratio ε, represented by the ratio of amplitude to depth, and the dispersion ratio μ, represented by the square of the ratio of depth to wave length, which quantify the relative importance of nonlinearity and dispersion. It derives an extended KdV equation of the interfacial waves using the method adopted by Dullin et al in the study of the surface waves when considering the order up to O(μ^2). As expected, the equation derived from the present work includes, as special cases, those obtained by Dullin et al for surface waves when the surface tension is neglected. The equation derived using an alternative method here is the same as the equation presented by Choi and Camassa. Also it solves the equation by borrowing the method presented by Marchant used for surface waves, and obtains its asymptotic solitary wave solutions when the weakly nonlinear and weakly dispersive terms are balanced in the extended KdV equation.
基金supported by National Science Foundation of China (11901020)Beijing Natural Science Foundation (1204026)the Science and Technology Project of Beijing Municipal Commission of Education China (KM202010005027)。
文摘Global in time weak solutions to the α-model regularization for the three dimensional Euler-Poisson equations are considered in this paper. We prove the existence of global weak solutions to α-model regularization for the three dimension compressible EulerPoisson equations by using the Fadeo-Galerkin method and the compactness arguments on the condition that the adiabatic constant satisfies γ >4/3.
基金supported by the National Natural Science Foundation of China(Nos.12001338,11871172)the Science and Technology Projects in Guangzhou(No.202201020132)the Youth fund of Shanxi University of Finance and Economics(No.QN-202021)。
文摘The nonlinear Schr?dinger(NLS for short)equation plays an important role in describing slow modulations in time and space of an underlying spatially and temporarily oscillating wave packet.In this paper,the authors study the NLS approximation by providing rigorous error estimates in Sobolev spaces for the electron Euler-Poisson equation,an important model to describe Langmuir waves in a plasma.They derive an approximate wave packet-like solution to the evolution equations by the multiscale analysis,then they construct the modified energy functional based on the quadratic terms and use the rotating coordinate transform to obtain uniform estimates of the error between the true and approximate solutions.
文摘We discuss structure-preserving numerical discretizations for repulsive and attractive Euler-Poisson equations that find applications in fluid-plasma and selfgravitation modeling.The scheme is fully discrete and structure preserving in the sense that it maintains a discrete energy law,as well as hyperbolic invariant domain properties,such as positivity of the density and a minimum principle of the specific entropy.A detailed discussion of algorithmic details is given,as well as proofs of the claimed properties.We present computational experiments corroborating our analytical findings and demonstrating the computational capabilities of the scheme.
基金supported in part by Chinese National Natural Science Foundation under grant 11201308Science Foundation for the Excellent Youth Scholars of Shanghai Municipal Education Commission(ZZyyyl2025)the innovation program of Shanghai Municipal Education Commission(13ZZ136)
文摘In this paper, we are concerned with the global existence of smooth solutions for the one dimen- sional relativistic Euler-Poisson equations: Combining certain physical background, the relativistic Euler-Poisson model is derived mathematically. By using an invariant of Lax's method, we will give a sufficient condition for the existence of a global smooth solution to the one-dimensional Euler-Poisson equations with repulsive force.
文摘In this study,a stable and robust interface-capturing method is developed to resolve inviscid,compressible two-fluid flows with general equation of state(EOS).The governing equations consist of mass conservation equation for each fluid,momentum and energy equations for mixture and an advection equation for volume fraction of one fluid component.Assumption of pressure equilibrium across an interface is used to close the model system.MUSCL-Hancock scheme is extended to construct input states for Riemann problems,whose solutions are calculated using generalized HLLC approximate Riemann solver.Adaptive mesh refinement(AMR)capability is built into hydrodynamic code.The resulting method has some advantages.First,it is very stable and robust,as the advection equation is handled properly.Second,general equation of state can model more materials than simple EOSs such as ideal and stiffened gas EOSs for example.In addition,AMR enables us to properly resolve flow features at disparate scales.Finally,this method is quite simple,time-efficient and easy to implement.
基金The first author was supported by the China Postdoctoral Science Foundation(2005037318)The second author acknowledges partial support from the Austrian-Chinese Scientific-Technical Collaboration Agreement, the CTS of Taiwanthe Wittgenstein Award 2000 of P.A. Markowich, funded by the Austrian FWF, the Grants-in-Aid of JSPS No.14-02036the NSFC(10431060)the Project-sponsored by SRF for ROCS, SEM
文摘A one-dimensional quantum hydrodynamic model (or quantum Euler-Poisson system) for semiconductors with initial boundary conditions is considered for general pressure-density function. The existence and uniqueness of the classical solution of the corresponding steady-state quantum hydrodynamic equations is proved. Furthermore, the global existence of classical solution, when the initial datum is a perturbation of t he steadystate solution, is obtained. This solution tends to the corresponding steady-state solution exponentially fast as the time tends to infinity.
基金supported by NSFC (10631030)the fund of CCNU for Ph.D Students (2009021)
文摘The motion of the self-gravitational gaseous stars can be described by the Euler-Poisson equations. The main purpose of this article is concerned with the nonlinear stability of gaseous stars in the non-isentropic case, when 34 γ2, S(x,t) is a smooth bounded function. First, we verify that the steady states are minimizers of the energy via concentration-compactness method; then using the variational approach we obtain the stability results of the non-isentropic flow.
基金Project supported by the National Natural Scienoe Foundation of China.
文摘1 Fundamental Equations of Two-fluid Model The complicated debris flow is simplified as two-fluid model of solid and liquid two-phase flow,of which the liquid phase is slurry with the fine particle and the solid phase is the coarse particle separated from slurry.The movement of each phase may be described by using a group of equations.The interaction of the two phases is cou-
基金supported by National Natural Science Foundation of China(Grant No.40890154)National Basic Research Program(Grant No.2005CB321700)+5 种基金supported by National Natural Science Foundation of China(Grant No.10701011)supported by National Natural Science Foundation of China(Grant No.10431060)Beijing Nova Program,Program for New Century Excellent Talentsin University,Huo Ying Dong Foundation(Grant No.111033)supported by National Natural Science Foundation of China(Grant No.10901011)Beijing Municipal Natural Science Foundation(Grant No.1102009)Foundation for Talents of Beijing(Grant No.20081D0501500171)
文摘The quasi-neutral limit of the multi-dimensional non-isentropic bipolar Euler-Poisson system is considered in the present paper. It is shown that for well-prepared initial data the smooth solution of the non-isentropic bipolar Euler-Poisson system converges strongly to the compressible non-isentropic Euler equations as the Debye length goes to zero.
基金Supported by the National Natural Science Foundation of China(12175072,11722546)。
文摘Using the two-fluid Tolman-Oppenheimer-Volkoff equation,the properties of dark matter(DM)admixed neutron stars(DANSs)have been investigated.In contrast to previous studies,we find that an increase in the maximum mass and a decrease in the radius of 1.4 M_(⊙)NSs can occur simultaneously in DANSs.This stems from the ability of the equation of state(EOS)for DM to be very soft at low density but very stiff at high density.It is well known that the IU-FSU and XS models are unable to produce a neutron star(NS)with a maximum mass greater than 2.0 M_(⊙).However,by considering the IU-FSU and XS models for DANSs,there are interactions with DM that can produce a maximum mass greater than 2.0 M_(⊙)and a radius of 1.4 M_(⊙)NSs below 13.7 km.When considering a DANS,the difference between DM with chiral symmetry(DMC)and DM with meson exchange(DMM)becomes obvious when the central energy density of DM is greater than that of nuclear matter(NM).In this case,the DMC model with a DM mass of 1000 MeV can still produce a maximum mass greater than 2.0 M_(⊙)and a radius of a 1.4 M_(⊙)NS below 13.7 km.Additionally,although the maximum mass of the DANS using the DMM model is greater than 2.0 M_(⊙),the radius of a 1.4 M_(⊙)NS can surpass 13.7 km.In the two-fluid system,the maximum mass of a DANS can be larger than 3.0 M_(⊙).Consequently,the dimensionless tidal deformabilityΛCP of a DANS with 1.4 M_(⊙),which increases with increasing maximum mass,may be larger than 800 when the radius of the 1.4 M_(⊙)DANS is approximately 13.0 km.
基金supported by the A.N.R.(Agence Nationale de la Recherche)through the projects SiNeRGHY(ANR-06-CIS6-009-01)and Anemos(ANR-11-MONU002).
文摘We present a new numerical method to approximate the solutions of an Euler-Poisson model,which is inherent to astrophysical flows where gravity plays an important role.We propose a discretization of gravity which ensures adequate coupling of the Poisson and Euler equations,paying particular attention to the gravity source term involved in the latter equations.In order to approximate this source term,its discretization is introduced into the approximate Riemann solver used for the Euler equations.A relaxation scheme is involved and its robustness is established.The method has been implemented in the software HERACLES[29]and several numerical experiments involving gravitational flows for astrophysics highlight the scheme.
基金This work was performed under the auspices of the U.S.Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344。
文摘The boundary plasma turbulence code BOUT models tokamak boundaryplasma turbulence in a realistic divertor geometry usingmodified Braginskii equations for plasma vorticity,density(ni),electron and ion temperature(Te,Ti)and parallelmomenta.The BOUT code solves for the plasma fluid equations in a three dimensional(3D)toroidal segment(or a toroidal wedge),including the region somewhat inside the separatrix and extending into the scrape-off layer;the private flux region is also included.In this paper,a description is given of the sophisticated physical models,innovative numerical algorithms,and modern software design used to simulate edgeplasmas in magnetic fusion energy devices.The BOUT code’s unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.