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931.
P. P. Krasnyuk 《International Applied Mechanics》2005,41(12):1357-1367
A mathematical formulation is given and a solution is found to the quasistatic contact problem of thermoelasticity for a rigid
heat-conducting punch moving over an elastic layer with fixed base. The interaction is accompanied by heating due to frictional
forces obeying Amonton’s law. The problem is reduced to a system of integral equations with time-varying limits of integration.
The structure of these equations depends on the type of thermal and physical conditions on the contact surface. An algorithm
is proposed for the numerical solution of this kind of equations. The variation in the contact pressure and contact area with
time is studied
__________
Translated from Prikladnaya Mekhanika, Vol. 41, No. 12, pp. 35–46, December 2005. 相似文献
932.
Numerical modeling of the time-dependent supersonic flow over a compression corner with different roundness radii is performed on the basis of the solution of the two-dimensional Navier-Stokes equations in the regimes corresponding to local boundary layer separation. The development of unstable disturbances generated by local periodic injection/suction in the preseparated boundary layer is calculated. The results are compared with those of similar calculations for a flat plate. It is shown that the natural oscillations of the boundary-layer second mode stabilize in the separation zone and grow intensely downstream of the reattachment point. The acoustic modes excited within a separation bubble are studied using numerical calculations and an asymptotic analysis. 相似文献
933.
添加聚合物对混合层流场特性影响的实验研究 总被引:1,自引:0,他引:1
叙述了适用于粘弹性流体混合层流场的实验装置的设计和研制.采用二维激光多普勒系统对混合层流场进行了测量,得到了平均速度剖面、动量厚度、湍流脉动强度、雷诺应力等一些流场的基本特征量.结果表明,混合层中加入聚合物后流场将有较大的变化,同时也说明本文所研制的实验装置满足实验的要求. 相似文献
934.
935.
本文将两相流动的雷诺方程沿深度方向进行平均,出求了平均后的运动方程、连续方程和能量方程式,在适当的物理假定下,简化得到可适用于考虑固-液流动及气-液流动两种情况下的两相层状流动基本方程. 相似文献
936.
M. A. Gschwendtner 《Heat and Mass Transfer》2004,40(6-7):561-572
The heat transfer from a rotating cylinder in an air-cross flow was investigated by purely optical measuring techniques. Flow velocities were measured by a two-dimensional LDV both in the vicinity of the cylinder and in the boundary layer. A new optical device based on light-deflection in a temperature field was developed to examine local temperature gradients in the boundary layer of the rotating cylinder. Finally, a Michelson-interferometer was installed to produce real-time pictures of isothermal lines around the heated cylinder. The impact of rotation on flow patterns, boundary layer behaviour and heat transfer could be clearly identified. It appears that the velocity-ratio acts like an independent parameter, in that flow patterns correspond to this dimensionless number. Furthermore, it seems that rotation dominates over cross flow, both fluid-dynamically and thermally above = 2.This work was carried out at the University of the Federal Armed Forces in Munich/Germany. 相似文献
937.
A computational study has been carried out to examine the effects of driver gas contamination in the NASA HYPULSE facility at GASL when operating with a detonation driver in reflected-shock tunnel mode. Unlike high-enthalpy shock tunnels which use helium as a driver gas, the driver gas in a detonation driver consists of a mixture of water vapour and argon, which has very different chemical and thermodynamic properties than those of helium. The purpose of the present work is to quantitatively evaluate the effects of driver gas contamination on the flow properties in the test section. Two computational analyses have been performed. The first analysis examined the nozzle flow under the influence of a prescribed level of driver gas contamination. In the second analysis, the transient development of the driver gas leakage in the reflected-shock region in the shock tube is studied. The unique flow features brought about by the detonation-driver gas and the method for detecting the contamination are discussed.Received: 6 August 2002, Revised: 22 September 2003, Published online: 10 February 2004Correspondence to: R.S.M. ChueAn abridged version of this paper was presented at the 23rd International Symposium on Shock Waves at Fort Worth, Texas, July 23 to 27, 2001 相似文献
938.
混合层强化混合的数值研究 总被引:2,自引:0,他引:2
受 Wang & Fiedler(1997)的实验的启发,采用高阶精度的差分格式,通过数值模拟的方法,研究了二维混合层及限于两平板间的二维混合层(二维受限混合层)入口处加振动对提高混合层混合效率的作用.计算结果表明:对二维混合层,振动的频率越低,在混合层中产生的大尺度涡结构的尺度越大,在频率很低时,涡具有相似性;对限于两平板间的二维混合层,在一定的振动频率下,混合层中产生的涡较大而且破碎得也较好,这将有利于混合.这一结论与 Wang & Fiedler(1997)的实验观测到的结果是一致的. 相似文献
939.
This article focuses on the formulation of a hysteretic model used as anisolator restoring force model. The proposed model is based on operatorgoverning input and output functions that depend on the deflection andthe restoring force of the isolator. First, the mathematical formulationis demonstrated, then the hysteretic model proposed is applied toisolators having different types of behavior. The model parameters aresought using the experimental force-deflection loop of each of theisolators studied. Next, the transient response of a flexible structuremounted on an all-metal isolator is predicted by coupling the firstorder differential equation of the restoring force and the second orderdifferential equations of the structure's motion. The experimentalinvestigation validates the proposed hysteretic model applied to theall-metal mount. 相似文献
940.
A combined theoretical and experimental study is presented for the interaction between crossing shock waves generated by (10°, 10°) sharp fins and a flat plate turbulent boundary layer at Mach 8.3. The theoretical model is the full 3-D mean compressible Reynolds-averaged Navier-Stokes RANS) equations incorporating the algebraic turbulent eddy viscosity model of Baldwin and Lomax. A grid refinement study indicated that adequate resolution of the flowfield has been achieved. Computed results agree well with experiment for surface pressure and surface flow patterns and for pitot pressure and yaw angle profiles in the flowfield. The computations, however, significantly overpredict surface heat transfer. Analysis of the computed flowfield results indicates the formation of complex streamline and wave structures within the interaction region.This article was processed using Springer-Verlag TEX Shock Waves macro package 1.0 and the AMS fonts, developed by the American Mathematical Society. 相似文献