Recently, we have applied an angular-spectrum based method, the thin-element decomposition (TED), to calculate SAW propagation in waveguide structures. However, the angular spectrum does not allow for reflections in t...
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Recently, we have applied an angular-spectrum based method, the thin-element decomposition (TED), to calculate SAW propagation in waveguide structures. However, the angular spectrum does not allow for reflections in the waveguide, which leads to discrepancies for long strips. This has lead us to use the Wigner-distribution function to describe the propagation of SAW in the paraxial limit. This approach leads to a ray-tracing type algorithm which is fast and easy to implement. We calculate wave propagation in a waveguide and compare the results to those given by the classical guided mode theory. We also discus the behaviour of Wigner distribution functions near sharp boundaries. We have also simulated expanding acoustic wavefronts produced by a point disturbance in a bulk. Due to elastic anisotropy of the solid, the energy flux associated with a plane wave is not collinear with the wave vector and, correspondingly, wave fronts (which correspond to the group-velocity surfaces) are not spherical.
In our previous paper[1] two weighted NND dtherence schemes were presentedby using proper weighted functions instead of minmod functions. As a result,the WNNDschemes enhance accuracy and yield smoother numrical auxes....
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In our previous paper[1] two weighted NND dtherence schemes were presentedby using proper weighted functions instead of minmod functions. As a result,the WNNDschemes enhance accuracy and yield smoother numrical auxes. In this paper two weightedENN schemes based on the ENN scheme[2] are constructed. The ENN scheme and WENNschemes are uniformly second-order accuracy and can achieve third-order accuracy in certainsmooth regions
Hybrid simulation includes both functional computer software models and actual hardware subsystems operating as an integrated whole. A ''hot test bed'' or a ''hybrid simulator-emulator''...
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Hybrid simulation includes both functional computer software models and actual hardware subsystems operating as an integrated whole. A ''hot test bed'' or a ''hybrid simulator-emulator'' enables design engineers to evaluate conceptual models in a more realistic real-lime context, but places increased cognitive demands on the designer. This paper describes an architecture, and results from a prototype implementation, for a design decision support system to allow a designer to make more productive and cost effective use of a test bed system.
This paper investigates the global convergence properties of the Fletcher-Reeves (FR) method for unconstrained optimization. In a simple way, we prove that a kind of inexact line search condition can ensure the conver...
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This paper investigates the global convergence properties of the Fletcher-Reeves (FR) method for unconstrained optimization. In a simple way, we prove that a kind of inexact line search condition can ensure the convergence of the FR method. Several examples are constructed to show that, if the search conditions are relaxed, the FR method may produce an ascent search direction, which implies that our result cannot be improved.
A class of hybrid algebraic multilevel preconditioning methods is presented for solving systems of linear equations with symmetric positive-definite matrices resulting from the discretization of many second-order elli...
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A class of hybrid algebraic multilevel preconditioning methods is presented for solving systems of linear equations with symmetric positive-definite matrices resulting from the discretization of many second-order elliptic boundary value problems by the finite element method. The new preconditioners are shown to be of optimal orders of complexities for 2-D and 3-D problem domains, and their relative condition numbers are estimated to be bounded uniformly with respect to the numbers of both levels and nodes.
We set up a class of parallel nonlinear multisplitting AOR methods by directly multisplitting the nonlinear mapping involved in the nonlinear complementarity problems. The different choices of the relaxation parameter...
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We set up a class of parallel nonlinear multisplitting AOR methods by directly multisplitting the nonlinear mapping involved in the nonlinear complementarity problems. The different choices of the relaxation parameters can yield all the known and a lot of new relaxation methods, as well as a lot of new relaxed parallel nonlinear multisplitting methods for solving the nonlinear complementarity problems. The two-sided approximation properties and the influences on the convergence rates from the relaxation parameters about our new methods are shown, and sufficient conditions guaranteeing the methods to converge globally are discussed. Finally, a lot of numerical results show that our new methods are feasible and efficient.
A new comparison theorem on the monotone convergence rates of the parallel nonlinear multisplitting accelerated overrelaxation (AOR) method for solving the large scale nonlinear complementarity problem is established....
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A new comparison theorem on the monotone convergence rates of the parallel nonlinear multisplitting accelerated overrelaxation (AOR) method for solving the large scale nonlinear complementarity problem is established. Thus, the monotone convergence theory of this class of method is completed.
In this paper, we propose the component-consistent pressure correction projection method for the numerical solution of the incompressible Navier-Stokes equations. This projection preserves a discrete form of the compo...
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In this paper, we propose the component-consistent pressure correction projection method for the numerical solution of the incompressible Navier-Stokes equations. This projection preserves a discrete form of the component-consistent condition between components of the solution at every time step. We also propose, in particular, the CNMT2 + CCPC method and the RKMT + CCPC method, both involving one pressure Poisson solution per time step. We show that they are both of O(Delta t(2)) for the Velocity and O(Delta t) for the pressure on fixed meshes and finite time intervals. Numerical tests on flow simulation support our claim that the component-consistent pressure correction projection method solves the deviation problem encountered sometimes by the original pressure correction projection method.
In this paper we generalize the method of constructing sympl ctic schemes by generating function in the case of autonomous Hamiltonian system to that of nonautonomous system.
In this paper we generalize the method of constructing sympl ctic schemes by generating function in the case of autonomous Hamiltonian system to that of nonautonomous system.
We set up a class of parallel nonlinear AOR method in the sense of matrix multi-splitting for solving the large scale system of nonlinear equations Ax + phi(x) = b with A is an element of L(R(n)) nonsingular, b is an ...
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We set up a class of parallel nonlinear AOR method in the sense of matrix multi-splitting for solving the large scale system of nonlinear equations Ax + phi(x) = b with A is an element of L(R(n)) nonsingular, b is an element of R(n) and phi : R(n) --> R(n) being continuously diagonal. The global as well as the monotone convergence of this method is proved.
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