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991.
A high-Reynolds steady-state viscous incompressible fluid flow is investigated in the neighborhood of a small three-dimensional irregularity located on the smooth surface of a body and oriented almost along the skin-friction lines. The regime in which quasi-two-dimensional flow with a given pressure gradient is realized on the irregularity scale is studied in detail. The numerical solution of the corresponding boundary value problem for the boundary layer equations is obtained. It is shown that, as distinct from the plane case, this solution is unique. 相似文献
992.
The paper presents a solution to the problem of thermal conduction and thermoelasticity for a thin shallow spherical shell
heated by a concentrated or local impulsive heat source moving over the shell surface. It is assumed that temperature is linearly
distributed across the shell thickness and that the shell, on its sides, exchanges heat with the environment in accordance
with Newton’s law of cooling. The Fourier and Laplace transforms are used to find an analytic solution. The dependence of
the temperature field and stress/strain components on the type of heating and the form of heat source is studied
__________
Translated from Prikladnaya Mekhanika, Vol. 42, No. 11, pp. 85–92, November 2006. 相似文献
993.
等达因图象的自动采集与识别 总被引:1,自引:0,他引:1
文中提出了一种机机械扫描系统.小功率激光器、图象板、相移元件、微机和程序软件组成的等达因图象自动采集与处理系统,用灰度值比较的思想实现了等达因图象的跟踪采集。提出了四幅图象相移法实现等达因图象的自动识别。系统能快速、实时、精确和全自动地实现等达因图象的记录和分析。给出与物体内各点应力状态一一对应的位相图。并用来研究了其他实验方法困难的局部三维效应问题。 相似文献
994.
995.
Hans-Otto Walther 《Journal of Dynamics and Differential Equations》2007,19(3):593-622
Automatic soft landing is modeled by a differential equation with state-dependent delay. It is shown that in the model soft
landing occurs for an open set of initial data, which is determined by means of a smooth invariant manifold.
相似文献
996.
997.
A nonlinear Galerkin/ Petrov- least squares mixed element (NGPLSME) method for the stationary Navier-Stokes equations is presented and analyzed. The scheme is that Petrov-least squares forms of residuals are added to the nonlinear Galerkin mixed element method so that it is stable for any combination of discrete velocity and pressure spaces without requiring the Babuska-Brezzi stability condition. The existence, uniqueness and convergence ( at optimal rate ) of the NGPLSME solution is proved in the case of sufficient viscosity ( or small data). 相似文献
998.
999.
曾文平 《应用数学和力学(英文版)》2000,21(9):1071-1078
IntroductionThispaperdealswiththeinitial_boundaryvalueproblemofthree_dimensionalheatconductionequationintheregionD :0≤x,y ,z≤L ,0 ≤t≤T u t= 2 u x2 2 u y2 2 u z2 ,u|x=0 =f1(y,z,t) , u|x=L =f2 (y ,z,t) ,u|y=0 =g1(z,x,t) , u|y=L =g2 (z,x,t) ,u|z=0 =h1(x ,y ,t) , u|z=L =h2 (x ,y ,t) ,u|t=0 =φ(x ,y,z) .(1 )(2 )… 相似文献
1000.
The Effect of C4H and C5H on the Microstructure of Aqueous Solutions of 1‐Alkyl‐3‐methylimidazolium Tetrafluoroborate Ionic Liquids 下载免费PDF全文
As is well‐known, the C2?H proton of 1‐ethyl‐3‐methylimidazolium tetrafluoroborate ([Emim]BF4) and 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([Bmim]BF4) has a strong ability to form hydrogen bonds. The purpose of this work is to evaluate the effect of the interactions of the C4?H and C5?H protons on the microstructure of [Emim]BF4 and [Bmim]BF4 with water by using 1H NMR spectroscopy. The differences between the relative 1H NMR chemical shifts of C2?H, C4?H, and C5?H and between the interaction‐energy parameters obtained from these chemical shifts are minor, thus suggesting that the interactions of C4?H and C5?H may have a considerable effect on the microstructure. To confirm this, the viscosities of the systems are estimated by using the interaction‐energy parameters obtained from the 1H NMR chemical shifts of the three studied aromatic protons and water, showing that the interactions of C4?H and C5?H also play an important role in the microstructure. 相似文献