44 research outputs found
Stability and flow fields structure for interfacial dynamics with interfacial mass flux
We analyze from a far field the evolution of an interface that separates
ideal incompressible fluids of different densities and has an interfacial mass
flux. We develop and apply the general matrix method to rigorously solve the
boundary value problem involving the governing equations in the fluid bulk and
the boundary conditions at the interface and at the outside boundaries of the
domain. We find the fundamental solutions for the linearized system of
equations, and analyze the interplay of interface stability with flow fields
structure, by directly linking rigorous mathematical attributes to physical
observables. New mechanisms are identified of the interface stabilization and
destabilization. We find that interfacial dynamics is stable when it conserves
the fluxes of mass, momentum and energy. The stabilization is due to inertial
effects causing small oscillations of the interface velocity. In the classic
Landau dynamics, the postulate of perfect constancy of the interface velocity
leads to the development of the Landau-Darrieus instability. This
destabilization is also associated with the imbalance of the perturbed energy
at the interface, in full consistency with the classic results. We identify
extreme sensitivity of the interface dynamics to the interfacial boundary
conditions, including formal properties of fundamental solutions and
qualitative and quantitative properties of the flow fields. This provides new
opportunities for studies, diagnostics, and control of multiphase flows in a
broad range of processes in nature and technology
Hydrodynamic Waves in Regions with Smooth Loss of Convexity of Isentropes. General Phenomenological Theory
General phenomenological theory of hydrodynamic waves in regions with smooth
loss of convexity of isentropes is developed based on the fact that for most
media these regions in p-V plane are anomalously small. Accordingly the waves
are usually weak and can be described in the manner analogous to that for weak
shock waves of compression. The corresponding generalized Burgers equation is
derived and analyzed. The exact solution of the equation for steady shock waves
of rarefaction is obtained and discusses.Comment: RevTeX, 4 two-column pages, no figure
Interface dynamics: Mechanisms of stabilization and destabilization and structure of flow fields
Interfacial mixing and transport are nonequilibrium processes coupling kinetic to macroscopic scales. They occur in fluids, plasmas, and materials over celestial events to atoms. Grasping their fundamentals can advance a broad range of disciplines in science, mathematics, and engineering. This paper focuses on the long-standing classic problem of stability of a phase boundary—a fluid interface that has a mass flow across it. We briefly review the recent advances in theoretical and experimental studies, develop the general theoretical framework directly linking the microscopic interfacial transport to the macroscopic flow fields, discover mechanisms of interface stabilization and destabilization that have not been discussed before for both inertial and accelerated dynamics, and chart perspectives for future research
Interface dynamics: Mechanisms of stabilization and destabilization and structure of flow fields
Interfacial mixing and transport are nonequilibrium processes coupling kinetic to macroscopic scales. They occur in fluids, plasmas, and materials over celestial events to atoms. Grasping their fundamentals can advance a broad range of disciplines in science, mathematics, and engineering. This paper focuses on the long-standing classic problem of stability of a phase boundary—a fluid interface that has a mass flow across it. We briefly review the recent advances in theoretical and experimental studies, develop the general theoretical framework directly linking the microscopic interfacial transport to the macroscopic flow fields, discover mechanisms of interface stabilization and destabilization that have not been discussed before for both inertial and accelerated dynamics, and chart perspectives for future research
Variational Quantum Eigensolver with Reduced Circuit Complexity
The variational quantum eigensolver (VQE) is one of the most promising
algorithms to find eigenvalues and eigenvectors of a given Hamiltonian on noisy
intermediate-scale quantum (NISQ) devices. A particular application is to
obtain ground or excited states of molecules. The practical realization is
currently limited by the complexity of quantum circuits. Here we present a
novel approach to reduce quantum circuit complexity in VQE for electronic
structure calculations. Our algorithm, called ClusterVQE, splits the initial
qubit space into subspaces (qubit clusters) which are further distributed on
individual (shallower) quantum circuits. The clusters are obtained based on
quantum mutual information reflecting maximal entanglement between qubits,
whereas entanglement between different clusters is taken into account via a new
"dressed" Hamiltonian. ClusterVQE therefore allows exact simulation of the
problem by using fewer qubits and shallower circuit depth compared to standard
VQE at the cost of additional classical resources. In addition, a new gradient
measurement method without using an ancillary qubit is also developed in this
work. Proof-of-principle demonstrations are presented for several molecular
systems based on quantum simulators as well as an IBM quantum device with
accompanying error mitigation. The efficiency of the new algorithm is
comparable to or even improved over qubit-ADAPT-VQE and iterative Qubit Coupled
Cluster (iQCC), state-of-the-art circuit-efficient VQE methods to obtain
variational ground state energies of molecules on NISQ hardware. Above all, the
new ClusterVQE algorithm simultaneously reduces the number of qubits and
circuit depth, making it a potential leader for quantum chemistry simulations
on NISQ devices
Multi-layered flyer accelerated by laser induced shock waves
Copyright 2000 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 7(2), 676-680, 2000 and may be found at http://dx.doi.org/10.1063/1.87385