PARALLELIZED UPWIND FLUX SPLITTING SCHEME FOR SUPERSONIC REACTING FLOWS ON UNSTRUCTURED HYBRID MESHES

A parallelized upwind flux splitting scheme for supersonic reacting flows on hybrid meshes is presented. The complexity of super/hyper-sonic combustion flows makes it necessary to establish solvers with higher resolution and efficiency for multi-component Euler/N-S equations. Hence, a spatial second-order van Leer type flux vector splitting scheme is established by introducing auxiliary points in interpolation, and a domain decomposition method used on unstructured hybrid meshes for obtaining high calculating efficiency. The numerical scheme with five-stage Runge-Kutta time step method is implemented to the simulation of combustion flows, including the supersonic hydrogen/air combustion and the normal injection of hydrogen into reacting flows. Satisfying results are obtained compared with limited references.

Third-Order Upwind Schemes for Convection Equations

Aim To construct a third order upwind scheme for convection equation. Methods Upwind Lagrange interpolation was used. Results and Conclusion The schemes L p stability for p∈ is proved. Numerical examples show that performance of the third order upwind scheme is better than that of most second order schemes.

A Wave Modulation Model of Ripples over Long Surface Waves

A study is presented on the modulation of ripples induced by a long surface wave (LW) and a new theoretical modula-tion model is proposed. In this model, the wind surface stress modulation is related to the modulation of ripple spectrum. The model results show that in the case of LW propagating in the wind direction with the wave age parameter of LW increasing, the area with enhanced shear stress shifts from the region near the LW crest on the upwind slope to the LW trough. With a smaller wave age parameter of LW, the ripple modulation has the maximum on the upwind slope in the vicinity of LW crest, while with a larger parameter the enhancement of ripple spectrum does not occur in that region. At low winds the amplitude of ripple modulation transfer function (MTF) is larger in the gravity wave range, while at moderate or high winds it changes little in the range from short gravity waves to capillary waves.

Field Studies of Frontal Area Index in Rangeland of Mongolia

Field observation was conducted at typical rangeland in Mongolia to examine the frontal area index. Frontal area index is the characteristics of surface roughness elements affecting sand transport. The frontal area was strongly correlated with the effective shelter length on sand transport in both short grasses and shrubs. The frontal area index was 0.031 and the relationship between the roughness length and frontal area index in this site agreed with past studies.

在广阔的世界上(组诗)

迎风 在侧面,我看不清她的脸 只觉得在草原上骑马 风声呼啸而过 高楼伸出的手背,卖菜人 在街头发出的叹息 都在迎着风 迎着风,露天里的人和事 他们当中 一部分被大风折断 另一部分 迎风前进。 生活随想 一本书翻了又翻 几个朋友。

An efficient adaptive finite element method algorithm with mass conservation for analysis of liquid face seals

To improve lubrication effect and seal performance, complicated geometrical hydrodynamic grooves or patterns are often processed on end faces of liquid lubricated mechanical seals. These structures can lead to difficulties in precisely estimating the seal performance. In this study, an efficient adaptive finite element method （FEM） algorithm with mass conservation was presented, in which a streamline upwind/Petrov-Galerkin （SUPG） weighted residual FEM and a fast iteration algorithm were applied to solve the lubrication equations （Reynolds equation）. A mesh adaptation technique was utilized to refine the computation domain based on a residual posterior error estimator. Validation, applicability, and efficiency were verified by comparison among different algorithms and by case studies on seals＇ faces with different groove structures. The study investigated the influence of the order of shape function and the mesh number on the leakage balance. Mesh refinement occurred mainly in cavitation zones when cavitation happened, otherwise it occurred in regions with a high pressure gradient. Numerical experiments verified that the proposed algorithm is a fast, effective, and accurate method to simulate lubrication problems in the engineering field apart from end face seals.

A 5th order monotonicity-preserving upwind compact difference scheme

Based on an upwind compact difference scheme and the idea of monotonicity-preserving, a 5th order monotonicity-preserving upwind compact difference scheme （m-UCD5） is proposed. The new difference scheme not only retains the advantage of good resolution of high wave number but also avoids the Gibbs phenomenon of the original upwind compact difference scheme. Compared with the classical 5th order WENO difference scheme, the new difference scheme is simpler and small in diffusion and computation load. By employing the component-wise and characteristic-wise methods, two forms of the new difference scheme are proposed to solve the N-S/Euler equation. Through the Sod problem, the Shu-Osher problem and tbe two-dimensional Double Mach Reflection problem, numerical solutions have demonstrated this new scheme does have a good resolution of high wave number and a robust ability of capturing shock waves, leading to a conclusion that the new difference scheme may be used to simulate complex flows containing shock waves.

Airflow patterns upwind of obstacles and their significance for echo dune formation:A field measurement of the effects of the windward slope angle

The velocities in front of five topographic obstacles with windward slope angles between 45~ and 80~ were measured using ul- trasonic anemometers in the field at the southeastern margin of the Tengger Desert. The characteristics of the horizontal and vertical velocities indicated that the airflow pattern was significantly influenced by the ohstacle＇s windward slope angle. The horizontal flow decelerated but the vertical flow accelerated upwind of the obstacles when the windward slope was less than 60~, but a reversed flow formed in front of steeper obstacles. The size of the area occupied by the reversed horizontal compo- nent increased with increasing windward slope, but the region of reversed vertical velocity became narrower and taller. Air- flow turbulence was strengthened as the wind approached the obstacle, and low-frequency high-energy velocity fluctuations were observed upwind of the obstacle, and could affect the entrainment and saltation processes of sand particles. Turbulence intensities for both the horizontal and vertical components of the airflow increased with increasing windward slope and with decreasing distance from the obstacle. The deceleration and downward movement of airflow upwind of the obstacle would re- sult in supersaturation of the air-sand flow, leading to deposition of moving sand, and these deposited grains would become the material basis for the formation of echo dunes. The reversed airflow would both determine the initial position of the echo dune and provide the necessary motive power to subsequently shape the echo dune.

A study of parameter-free shock capturing upwind schemes on low speeds' issues

Nowadays,the upwind schemes are in a rapid development to capture shock accurately.However,these upwind schemes’properties at low speeds,such as their reconstruction scheme dependencies,grid dependencies,and Mach number dependencies,are concerned by few people.In this paper,a systematic study on their low speeds’issues is conducted.Through a series of tests,we can find that most parameter-free upwind schemes,widely used in practice today,are not applicable to low speeds’simulations.In contrast,SLAU and SLAU2 can give reliable results.Also,the upwind scheme’s influence on the accuracy is stronger than the reconstruction scheme’s influence at low speeds.

Effect of three vertigo-stopping needles on neurohumor of patients with cervical vertigo:a controlled trial

Objective To observe the effect of three vertigo-stopping needles on the contents of neuropeptide Y （NPY）, endothelin （ET） and calcitonin gene-related peptide （CGRP） in plasma of patients with cervical vertigo, and to explore its mechanism of treatment. Methods One hundred and eighty patients with cervical vertigo were divided into group A [acupuncture at R6nyfng （人迎ST 9） and Fengchi （风池 GB 20）, and frontal line], group B [acupuncture at Jing jiaji （颈夹脊）, GB 20 and Baihui （百会 GV 20）] and group C [intravenous infusion with ligustrazine and oral administration with flunarizine] according to simple randomization, with 60 cases in each group. For the patients in group A and group B, the treatment was conducted once a day, and ten times were considered as one course of treatment. Two days were free of treatment between two courses, and two courses were needed. For the patients in group C, the treatment was conducted for fifteen days. The contents of NPY, ET and CGRP in plasma before and after treatment were detected in patients with cervical vertigo. Results The contents of NPY in plasma of patients in the three groups after treatment were markedly lower than that before treatment （all P〈0.01）, and the differences were not statistically significant when compared the descending degrees among three groups （P〉0.05）. The contents of ET in plasma of patients in the three groups after treatment were markedly lower than that before treatment （P〈0.05, P〈0.01）, the descending degree in group A was greater than that in group B and group C, and the difference was statistically significant （P〈0.O1, P〈O.05）; while the difference was not statistically significant when compared the descending degrees between group B and group C （P〉0.05）. The contents of CGRP in plasma of patients in the three groups after treatment were markedly higher than that before treatment （P〈0.05, P〈O.O1）, the increasing degree in group A was greater than that in group B and group C, and the difference was statistically significant （both P〈0.05）; while the difference was not statistically significant when compared the increasing degrees between group B and group C （P〉0.05）. Conclusion Three vertigo-stopping needles, acupuncture and medication can regulate the contents of NPY, ET and CGRP in plasma of patients with cervical vertigo, while three vertigo-stopping needles is significantly superior to acupuncture and medication in reducing ET and increasing CGRP.

l^1-error estimates on the immersed interface upwind scheme for linear convection equations with piecewise constant coefcients: A simple proof

A linear convection equation with discontinuous coefficients arises in wave propagation through interfaces. An interface condition is needed at the interface to select a unique solution. An upwind scheme that builds this interface condition into its numerical flux is called the immersed interface upwind scheme. An ι1-error estimate of such a scheme was first established by Wen et al. （2008）. In this paper, we provide a simple analysis on the ι1-error estimate. The main idea is to formulate the solution to the underline initial-value problem into the sum of solutions to two convection equations with constant coefficients, which can then be estimated using classical methods for the initial or boundary value problems.

Clinical Study on Puncturing Renying （ST 9） to Treat Poststroke Dysphagia

Objective： To observe the clinical efficacy of puncturing Renying （ST 9） in the treatment of poststroke dysphagia. Methods： Sixty cases of poststroke dysphagia were randomized into two groups, a control group in which 30 cases were given rehabilitation training, and a treatment group in which 30 cases were treated by puncturing Renying （ST 9） and rehabilitation training, with a course of four weeks. Results： The total effective rate for dysphagia was higher in the treatment group than in the control group （P〈0.05）. Conclusion： Puncturing Renying （ST 9） is quite effective for poststroke dysphagia.

A parameter-free upwind scheme for all speeds' simulations

With the rapid development of the computational fluid dynamics(CFD),a parameter-free upwind scheme capable of simulating all speeds accurately and efficiently is in high demand.To achieve this goal,we present a new upwind scheme called AUSMPWM in this paper.This scheme computes the numerical mass flux as the AUSMPW+and computes the interfacial sound speed in a different way.Also,it computes the pressure flux by limiting the dissipation if the Mach number is less than 1.Series of numerical experiments show that AUSMPWM can satisfy the following attractive properties independent of any tuning coefficient:(1)Robustness against the shock anomaly and high discontinuity’s resolution;(2)high accuracy on hypersonic heating prediction and capability to give smooth reproductions of heating profiles;(3)low dissipation at low speeds;and(4)strong grid,reconstruction scheme,and Mach number independence in low speeds’simulations.These properties suggest that AUSMPWM is promising to be widely used to accurately and efficiently simulate flows of all speeds.

UPWIND FINITE VOLUME ELEMENT METHODS FOR ONE-DIMENSIONAL SEMICONDUCTOR DEVICE

This work is supported in part-by Shandong Province Natural Science Foundation under Grant No. ZR2010AQ010 and a Project of Shandong Province Higher Educational Science and Technology Program under Grant Nos. JllLA09 and J10LA01.