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1.
T. S. Lee 《国际流体数值方法杂志》1990,11(8):1113-1126
The flow fields in the neighbourhood of double constrictions in a circular cylindrical tube were studied numerically. The effects on the streamline, velocity and vorticity distributions as the flow passes through the constrictions in the tube were studied in the Reynolds number range 5–200. Double constrictions with dimensionless spacing ratios of 1, 2, 3 and ∞ were studied for a 50% constriction. It is noted that when the Reynolds number is below 10, no recirculation region is formed in the above constricted flow. For Reynolds numbers greater than 10, a recirculation region forms downstream of each of the constrictions. For constriction spacing ratios of 1, 2, and 3, when the Reynolds number is high, a recirculation region spreads between the valley of the constrictions. The recirculation region formed between the two constrictions has a diminishing effect on the generation of wall vorticity near the second constriction area. In general, the peak value of wall vorticity is found slightly upstream of each of the constrictions. When the Reynolds number is increased, the peak wall vorticity value increases and its location is moved upstream. Maximum wall vorticity generated by the first constriction is found to be always greater than the maximum wall vorticity generated by the second constriction. The extent of this spreading of the recirculation region from the first constriction and its effects on the second constriction depend on the constriction spacing ratio and the flow Reynolds number. 相似文献
2.
A semi-analytical streamline-based model, employing stratification and macro physics only, is developed and utilized to simulate
injection/production phases of single-well push–pull tests. Modeling results are compared with experimental field data, giving
an excellent match, without resorting to parameter fitting, simply by putting in known test-site properties, such as stratification
data, hydraulic head gradients, and test parameters. 相似文献
3.
A direct streamline upwind method has been developed for convection-dominated flow problems utilizing quadratic elements. The approach presented retains the curve-sidedness feature offered by these elements. This facilitates the use of boundary conforming elements in domains that possess extreme curvature such as turbomachinery bladed components, for which the method is particularly suited. Three test cases are solved to evaluate the stability and diffusive characteristics of the numerical solution. The results presented clearly demonstrate that the proposed method does not exhibit any non-physical spatial oscillations, nor does it suffer from the traditional problem of excessive numerical diffusion. 相似文献
4.
孙同军 《高校应用数学学报(英文版)》2001,16(1):63-71
Abastract. In this paper,a streamline-diffusion F. E. M. for linear Sobolev equations with con-vection-dominated term is given. According to the range of space-time F. E mesh parameter h,two choices for artifical diffusion parameter are presented,and for the corresponding computa-tion schemes the stability and error estimates in suitable norms are estabilished. 相似文献
5.
对流占优扩散问题的经济型流线扩散有限元法 总被引:6,自引:1,他引:5
In this paper, the economical finite difference-streamline diffusion (EFDSD) schemes based on the linear F.E. space for time-dependent linear and non-linear convection-dominated diffusion problems are constructed. The stability and error estimation with quasi-optimal order approximation are established in the norm stronger than L^2 - norm for the schemes considered. It is indicated by the results obtained that,for linear F.E. space, the EFDSD schemes have the same specific properties of stability and convergence as the traditional FDSD schemes for the problems discussed. 相似文献
6.
7.
Isogeometric analysis (IGA), in combination with the streamline upwind Petrov–Galerkin (SUPG) stabilization, is studied for the discretization of steady-state convection–diffusion equations. Numerical results obtained for the Hemker problem are compared with results computed with the SUPG finite element method of the same order. Using an appropriate parameterization for IGA, the computed solutions are much more accurate than those obtained with the finite element method, both in terms of the size of spurious oscillations and of the sharpness of layers. 相似文献
8.
Wei Boon Yap Beng Ti Tey Noorjahan Banu Mohamed Alitheen Wen Siang Tan 《Journal of chromatography. A》2010,1217(21):3473-3480
Hepatitis B core antigen (HBcAg) is used as a diagnostic reagent for the detection of hepatitis B virus infection. In this study, immobilized metal affinity-expanded bed adsorption chromatography (IMA-EBAC) was employed to purify N-terminally His-tagged HBcAg from unclarified bacterial homogenate. Streamline Chelating was used as the adsorbent and the batch adsorption experiment showed that the optimal binding pH of His-tagged HBcAg was 8.0 with a binding capacity of 1.8 mg per ml of adsorbent. The optimal elution condition for the elution of His-tagged HBcAg from the adsorbent was at pH 7 in the presence of 500 mM imidazole and 1.5 M NaCl. The IMA-EBAC has successfully recovered 56% of His-tagged HBcAg from the unclarified E. coli homogenate with a purification factor of 3.64. Enzyme-linked immunosorbent assay (ELISA) showed that the antigenicity of the recovered His-tagged HBcAg was not affected throughout the IMA-EBAC purification process and electron microscopy revealed that the protein assembled into virus-like particles (VLP). 相似文献
9.
Long Chen Yonggang Wang Jinbiao Wu 《Journal of Computational and Applied Mathematics》2008,220(1-2):712-724
A one-dimensional singularly perturbed problem with a boundary turning point is considered in this paper. Let Vh be the linear finite element space on a suitable grid . A variant of streamline diffusion finite element method is proved to be almost uniform stable in the sense that the numerical approximation uh satisfies u-uh∞C|lnε| infvhVhu-vh∞, where C is independent with the small diffusion coefficient ε and the mesh . Such stability result is applied to layer-adapted grids to obtain almost ε-uniform second order scheme for turning point problems. 相似文献
10.