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This study extends the upstream flux‐splitting finite‐volume (UFF) scheme to shallow water equations with source terms. Coupling the hydrostatic reconstruction method (HRM) with the UFF scheme achieves a resultant numerical scheme that adequately balances flux gradients and source terms. The proposed scheme is validated in three benchmark problems and applied to flood flows in the natural/irregular river with bridge pier obstructions. The results of the simulations are in satisfactory agreement with the available analytical solutions, experimental data and field measurements. Comparisons of the present results with those obtained by the surface gradient method (SGM) demonstrate the superior stability and higher accuracy of the HRM. The stability test results also show that the HRM requires less CPU time (up to 60%) than the SGM. The proposed well‐balanced UFF scheme is accurate, stable and efficient to solve flow problems involving irregular bed topography. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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76.
We reduce the solution of contact problems in the interaction of rigid bodies (dies) with thin-walled elements (one-dimensional
problems) to Volterra integral equations. We study the effect of the model describing the stress-strain state of plates on
the type of integral equations and the structure of their solutions. It is shown that taking account of reducing turns the
problem into a Volterra integral equation of second kind, which has a unique solution that is continuous and agrees quite
well with the results obtained from the three-dimensional theory. In the case of a theory of Timoshenko type the problem is
reduced to a Volterra three-dimensional theory. In the case of a theory of Timoshenko type the problem is reduced to a Volterra
integral equation of first kind that has a unique continuous solution; but for dies without corners the Herz condition does
not hold (p(a) ≠ 0), and the contact pressure assumes its maximal value at the end of the zone of contact. For thin-walled
elements, whose state can be described by the classical Kirchhoff-Love theory, the integral equation of the problem (a Volterra
equation of first kind) has a solution in the class of distributions. The contact pressure is reduced to concentrated reactions
at the extreme points of the contact zone. We give a comparative analysis of the solutions in all the cases just listed (forces,
normal displacements, contact pressures). Three figures, 1 table. Bibliography: 5 titles.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 27, 1997, pp. 96–103. Original article submitted March 15, 1997. 相似文献
77.
Francis K. Fong 《Applied Physics A: Materials Science & Processing》1975,6(2):151-166
In this paper, the molecular details of the recently proposed energy upconversion theory of photosynthesis are reviewed. The primary light reactions are explained in terms of aC 2 symmetrical structure of the reaction center involving a (Chl?H2O)2 adduct. It is shown that exciton interaction within the (Chl?H2O)2 complex leads to an antisymmetric triplet state which may act as an energy trap. The presence of the energy trap in the reaction center suggests that the trigger step for the photoionization of active chlorophylls may involve the summation of two red excitation photons. Under normal conditions, the steadystate one-photon-per-electron quantum requirement is obtained. The functional properties of the various molecular constituents of the Chl-a molecule, such as the Ring V β-ketoester group, the phytyl tail, the central Mg atom, and the π-system of the macrocycle are explained within the present theoretical framework. A detailed analysis is given of the postulates and the consequences of the proposed model. The ramifications of the theory are probed, and their biological consequences are suggested for future study. 相似文献
78.
Band structures of SbSBr and SbSeI have been obtained by using the empirical pseudopotential method (EPM) to fit our measured optical reflectivity data and earlier gap measurements. An SbSI band structure has been determined by fitting to earlier reflectivity and Raman spectroscopic data, and the results agree better with the data than do the results of an earlier preliminary EPM calculation. Secondary conduction band minima may in part be responsible for the observed microwave oscillation (Gunn effect) in SbSI. Similar minima in SbSBr and SbSeI are reported, suggesting these crystals might also show microwave properties. The total densities of states are presented. 相似文献
79.
C. F. Chan Man Fong 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1976,27(1):115-118
Summary It has been found that the effect of a radial temperature gradient on the Taylor stability problem for a viscoelastic fluid and for a Newtonian fluid is the same.
Résumé On montre que l'effet d'un gradient de la température radial sur le problème de stabilité de Taylor pour un fluide viscoélastique est semblable à celui d'un fluide Newtonien.相似文献
80.
Alexopoulos T Arenton M Barbosa RF Barker AR Bellantoni L Bellavance A Blucher E Bock GJ Cheu E Childress S Coleman R Corcoran MD Cox B Erwin AR Ford R Glazov A Golossanov A Graham J Hamm J Hanagaki K Hsiung YB Huang H Jejer V Jensen DA Kessler R Kobrak HG Kotera K LaDue J Ledovskoy A McBride PL Monnier E Nelson KS Nguyen H Niclasen R Prasad V Qi XR Ramberg EJ Ray RE Ronquest M Santos E Shanahan P Shields J Slater W Smith D Solomey N Swallow EC Toale PA Tschirhart R Wah YW Wang J White HB 《Physical review letters》2004,93(18):181802
We present a determination of the Cabibbo-Kobayashi-Maskawa parameter |V(us)| based on new measurements of the six largest K(L) branching fractions and semileptonic form factors by the KTeV (E832) experiment at Fermilab. We find |V(us)|=0.2252+/-0.0008(KTeV)+/-0.0021(ext), where the errors are from KTeV measurements and from external sources. We also use the measured branching fractions to determine the CP violation parameter |eta(+-)|=(2.228+/-0.005(KTeV)+/-0.009(ext))x10(-3). 相似文献