Numerical analysis on longitudinal location optimization of vortex generator in compact heat exchangers

In this paper, numerical, curvilinear and turbulent model has been used to investigate the effect of vortex generator's longitudinal displacement on heat transfer and fluid flow in different Reynolds numbers ranging from 500 to 3000. The numerical model has been validated with experimental results of a former study, which is resembled in a particular case. Numerical simulation shows that the vorticity enhancement would increase both Nusselt number and pressure drop. Proposed trend is not constant and the pattern in which parameters change is dependent on Reynolds number. Finally, a conjugated optimization of pressure drop and the Nusselt number has been suggested based on the order of parameter changes. Copyright © 2010 John Wiley & Sons, Ltd.     

The smallest eigenvalue of large Hankel matrices generated by a deformed Laguerre weight

We study the asymptotic behavior of the smallest eigenvalue, λ_N, of the Hankel (or moments) matrix denoted by , with respect to the weight . An asymptotic expression of the polynomials orthogonal with w(x) is established. Using this, we obtain the specific asymptotic formulas of λ_N in this paper. Applying a parallel numerical algorithm, we get a variety of numerical results of λ_N corresponding to our theoretical calculations.     

Numerical study of a conservative weighted compact difference scheme for the symmetric regularized long wave equations

In this article, a new weighted and compact conservative difference scheme for the symmetric regularized long wave (SRLW) equations is considered. The new scheme is decoupled and linearized in practical computation, that is, at each time step only two tridiagonal systems of linear algebraic equations need to be solved. It is proved by the discrete energy method that the compact scheme is uniquely solvable, the convergence and stability of the difference scheme are obtained, and its numerical convergence order is in the ‐norm. Numerical experiment results show that the scheme is efficient and reliable.     

Numerical simulation for 2D double-diffusive convection (DDC) in rectangular enclosures based on a high resolution upwind compact streamfunction model I: numerical method and code validation

Applied Mathematics and Mechanics - A high resolution upwind compact streamfunction numerical algorithm for two-dimensional (2D) double-diffusive convection (DDC) is developed. The unsteady...     

A generalised finite difference scheme based on compact integrated radial basis function for flow in heterogeneous soils

In the present paper, we develop a generalised finite difference approach based on compact integrated radial basis function (CIRBF) stencils for solving highly nonlinear Richards equation governing fluid movement in heterogeneous soils. The proposed CIRBF scheme enjoys a high level of accuracy and a fast convergence rate with grid refinement owing to the combination of the integrated RBF approximation and compact approximation where the spatial derivatives are discretised in terms of the information of neighbouring nodes in a stencil. The CIRBF method is first verified through the solution of ordinary differential equations, 2–D Poisson equations and a Taylor‐Green vortex. Numerical comparisons show that the CIRBF method outperforms some other methods in the literature. The CIRBF method in conjunction with a rational function transformation method and an adaptive time‐stepping scheme is then applied to simulate 1–D and 2–D soil infiltrations effectively. The proposed solutions are more accurate and converge faster than those of the finite different method used with a second‐order central difference scheme. Additionally, the present scheme also takes less time to achieve target accuracy in comparison with the 1D‐IRBF and higher order compact schemes.     

A ferroelectric liquid crystal spatial light modulator encoded with orthogonal arrays and its optimized design for laser speckle reduction

In laser projectors, speckle reduction can be achieved by projecting a changing binary phase diffuser onto the screen. Here, we sequentially encoded a commercialized ferroelectric liquid crystal spatial light modulator (FLC-SLM) with the rows of a two-level orthogonal array of order sixty-four, thus obtaining a changing binary phase diffuser. With the help of this binary phase diffuser, the subjective speckle contrast ratio on the screen is reduced from C_b=0.71 to C_a=0.1. Based on the experimental results, a simplified transparent FLC-SLM design is first proposed. This newly designed FLC-SLM has two phase modulation depths and can be driven with the passive matrix addressing scheme. Therefore, the control electronics of the proposed FLC-SLM can be significantly simplified compared to the currently used one.     

提取医用黄腐酸的优化方案

本文介绍如何用正交试验法选择提取医用黄腐酸的最优方案 ,使提取出的医用黄腐酸达到最佳提取率 ,并符合国家药典标准     

Hopf C*-algebras related to the Latin square

A sufficient condition is given for the multiparametric Hopf algebras to be Hopf* -algebras. Then a special subclass of the -algebra related to a Latin square is given. After being completed, its generators are all of norm one.     

Some Fixed Point Results on a Class of Contractive Mappings in Cone Metric Spaces

In this paper, we consider a notion of contractive mappings with certain conditions in cone metric spaces and obtain some results of fixed points by using some necessary conditions. The results directly improve and generalize some fixed point results in metric soaces and some previous results in cone metric spaces.