This paper studies the phase effect in mode coupling of Kelvin-Helmholtz instability in two-dimensionalincompressible *** is found that there is an important growth phenomenon of every mode in the mode *** growth chan...
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This paper studies the phase effect in mode coupling of Kelvin-Helmholtz instability in two-dimensionalincompressible *** is found that there is an important growth phenomenon of every mode in the mode *** growth changes periodically with phase difference and in the condition of our simulation the period is about0.7π.The period characteristic is apparent in all stage of the mode coupling process,especially in the relatively laterstage.
作者：
叶文华王立锋贺贤土Department of Physics
Zhejiang University Hangzhou 310027 CAPT
Peking University Beijing 100871 LCP
Institute of Applied Physics and Computational Mathematics Beijing 100088 SMCE
China University of Mining and Technology Beijing 100083
We report the formation of jet-like long spike in the nonlinear evolution of the ablative Rayleigh-Taylor instability （ARTI） experiments by numerical simulations. A preheating model k（T） = KSH[1＋f（T）], where KS...
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We report the formation of jet-like long spike in the nonlinear evolution of the ablative Rayleigh-Taylor instability （ARTI） experiments by numerical simulations. A preheating model k（T） = KSH[1＋f（T）], where KSH is the Spitzer Harm （SH） electron conductivity and f（T） interprets the preheating tongue effect in the cold plasma ahead of the ablative front [Phys. Rev. E 65 （2002） 57401], is introduced in simulations. The simulation results of the nonlinear evolution of the ARTI are in general agreement with the experiment results. It is found that two factors, i.e., the suppressing of ablative Kelvin Helmholtz instability （AKHI） and the heat flow cone in the spike tips, contribute to the formation of jet-like long spike in the nonlinear evolution of the ARTI.
A radiative shock(RS)is one in which the density and temperature structures are affected by radiation from the shock-heated *** plays a special role in astrophysics as it nontrivially combines both hydrodynamics and r...
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A radiative shock(RS)is one in which the density and temperature structures are affected by radiation from the shock-heated *** plays a special role in astrophysics as it nontrivially combines both hydrodynamics and radiation *** most astrophysical shocks,the temperature and density conditions lead to strong emission,with radiation thus playing a major role therein.
The penetration behavior and perforation characteristics of Kevlar/Epoxy laminates with various thickness in quasi-static and ballistic perforation penetrated by steel projectiles with different noses are investigated...
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The penetration behavior and perforation characteristics of Kevlar/Epoxy laminates with various thickness in quasi-static and ballistic perforation penetrated by steel projectiles with different noses are investigated. Quasi-static tests are conducted on MTS810 testing system. The results indicate that global deformation is the major mechanism of energy absorption and woven laminates exhibit larger energy dissipation than that of angle-plied laminates. Therefore, the woven laminates have better quasi-static penetration resistance. Ballistic tests with velocity of 200-700 m/s are executed by using a powder gun with 7.62 mm barrel. Comparing ballistic experimental results with those under quasi-static condition, both the perforation performance and the failure modes are related closely to the speed of penetrator. Quite different from quasi-static tests, ballistic tests indicate that thick angle-plied laminate targets are even better than woven laminates in resisting ballistic impact. It is observed that the damage zone of the laminate is localized highly with the increasing of the impact velocity and correspondingly, the failure modes are more manifold. The shape of projectile noses affects the impact resistance of laminated Kevlar significantly in the range of velocity around the ballistic limit..
The sixth-order accurate phase error flux-corrected transport numerical algorithm is introduced, and used to simulate Kelvin-Helmholtz instability. Linear growth rates of the simulation agree with the linear theories ...
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The sixth-order accurate phase error flux-corrected transport numerical algorithm is introduced, and used to simulate Kelvin-Helmholtz instability. Linear growth rates of the simulation agree with the linear theories of Kelvin Helmholtz instability. It indicates the validity and accuracy of this simulation method. The method also has good capturing ability of the instability interface deformation.
Using a semiclassical model,we investigate the effect of the initial longitudinal velocity of the tunnel-ionized electron on low-energy structure(LES)in above-threshold ionization(ATI)*** analysis shows that the effec...
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Using a semiclassical model,we investigate the effect of the initial longitudinal velocity of the tunnel-ionized electron on low-energy structure(LES)in above-threshold ionization(ATI)*** analysis shows that the effect(reduction or enhancement)of the initial longitudinal velocity pz0 on the LES is dependent on the direction of the initial longitudinal *** the initial longitudinal velocity along the direction of the laser electric field at the moment of tunneling(i.e.,pz0>0),the Coulomb interaction between the photoelectron and ion core is enhanced,while for the initial longitudinal velocity in the opposite direction(i.e.,pz0<0),the Coulomb effect is *** work provides solid evidence that the initial electron longitudinal velocity has considerable effect on the photoelectron dynamics in the ATI process.
In this paper, a new discrete formulation and a type of new posteriori error estimators for the second-order element discretization for Stokes problems are presented, where pressure is approximated with piecewise fir...
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In this paper, a new discrete formulation and a type of new posteriori error estimators for the second-order element discretization for Stokes problems are presented, where pressure is approximated with piecewise first-degree polynomials and velocity vector field with piecewise second-degree polynomials with a cubic bubble function to be added. The estimators are the globally upper and locally lower bounds for the error of the finite element discretization. It is shown that the bubble part for this second-order element approximation is substituted for the other parts of the approximate solution.
We present a continuous formulation of machine learning,as a problem in the calculus of variations and differential-integral equations,in the spirit of classical numerical *** demonstrate that conventional machine lea...
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We present a continuous formulation of machine learning,as a problem in the calculus of variations and differential-integral equations,in the spirit of classical numerical *** demonstrate that conventional machine learning models and algorithms,such as the random feature model,the two-layer neural network model and the residual neural network model,can all be recovered(in a scaled form)as particular discretizations of different continuous *** also present examples of new models,such as the flow-based random feature model,and new algorithms,such as the smoothed particle method and spectral method,that arise naturally from this continuous *** discuss how the issues of generalization error and implicit regularization can be studied under this framework.
We demonstrate the constant feedback and the modified constant feedback method to the Hénon map. Using the convergence of the chaotic orbit in finite time, we can control the system from chaos to the stable fixed...
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We demonstrate the constant feedback and the modified constant feedback method to the Hénon map. Using the convergence of the chaotic orbit in finite time, we can control the system from chaos to the stable fixed point, and even to the stable period-2 orbit or higher periodic orbit by the action of a proper feedback strength and pulse interval. We also find that the multi-steady solutions appear with the same control strength and different initial conditions. The aim of this control method is explicit and the feedback strength is easy to determine. The method is robust under the presence of weak external noise.
High-resolution collinear laser spectroscopy of neutron-rich actinium has been performed at TRIUMF’s isotope separator and accelerator facility ISAC. By probing the 7s2 1S0 → 6d7p 1P1 ionic transition, the hyperfine...
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