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ae-mail : guemmadi_samah@yahoo.fr , be-mail : ouibraah@live.fr *Corresponding author : ouibraah@live.fr Key words: Journal bearing, Lubrication, Maxwell model, Viscoelastic fluids, CFD.
Owing to the complexity of the associated hydrodynamic equations, numerical computation is widely used, involving different CFD (Computational Fluid Dynamic) analysis and programs [2, 4, 5, 8, 10, 11], compared to analytical approaches [12].
Boundary Conditions: We use of course the usual well known boundary conditions [1, 4, 5]: a) for the velocity field: (6) h(q) corresponds to a given fluid particle position in the core and is given [1, 4, 5] by : (7) b) for the pressure and the stress field: (8) Numerical Procedure The above equations systems (2) to (5) together with (6) to (8) for given geometric and kinematic characteristics of this 2D flow, are numerically solved using the CFD package Fluent 6.3 completed by UDF.
Papadopoulos, CFD analysis of journal bearing hydrodynamic lubrication by Bingham lubricant, Tribology International, Vol. 41 pp. 1190-1204. (2008)
Clermont, Numerical Simulations of non-Newtonian flow between eccentric cylinders by domain decomposition and stream tube method Journal of Non-Newtonian Fluid Mechanics, 126, pp. 175-158, (2005)

In order to ensure the consistency of simulation and actual condition, simulation of full flow field should be conducted for those impellers.
Results Analysis The pressure and relative velocity distributions inside the impellers are obtained in the CFD-POST of ANSYS.
Three-Dimensional Numerical Simulation of Internal Flow Within the Impeller of Roto-Jet Pump.
Numerical Simulation and Optimization Analysis for Roto-Jet Pump Based on CFD [D].
Analysis of energy losses and numerical simulation of flow field in the roto-jet pump.

Using CFD type grid to mesh the unit, the substrate material is copper, and working fluid is water.
So when the number of mesh exceeds 24400, the simulation has little dependence on mesh.
Numerical simulations were performed by varying the aspect ratio of the micro-channels in the range.
In the range, 12 aspect ratio are selected to numerical simulation.
(2) From the results of the numerical simulation and analysis，the rectangular micro-channel heat sinks have good working performance when the aspect radio between 10 to 20.

Numerical Simulation of Gas Exchange Process in Two Stroke Reverse-loop Scavenging Engines Qing Zhu1,b, Zhaocheng Yuan1,a, Wencui Guo1,c,and Yingxiao Yu1,2,d 1State Key Laboratory of Automotive Simulation and Control of Jilin University, Changchun, China 2Department of Aviation Life-saving, Aviation University of Air Force, Changchun, China ayuanzc0528@126.com,bqingzhu630@126.com,c364590985@qq.com, dloopa@126.com Keywords：Two Stroke Diesel Engine, Reverse-Loop Scavenging, Gas Exchange Process, Numerical Simulation Abstract.
In this model, the piston rings had been left out for making the model simple and no much influence on simulation.
Conclusions (1) Air-exchange problems of two stroke engine is described simply by simulation analysis.
This 3D CFD simulation of two stroke Reverse-Loop scavenging engine in domestic is infrequent
References [1]Jakob.Fredriksson,Ingemar.Denbratt, “Simulation of a Two-Stroke Free Piston Engine”,SAE paper 2004 -01-1871

Reynolds averaged NS equation is the average variable flow control equation, and its associated simulation theory is called turbulence model theory.
Outlet boundary condition is setting to pressure outlet, relative pressure is setting to zero, body boundary is setting to no-slip wall, wall boundary is setting to free-slip wall. 4 The Simulation of low-speed wind tunnel tests by CFD simulation The Simulation of low speed wind tunnel tests used to measure the position force [5-6], designed to test conditions as shown in Table 1.
Fig.4 Simulation of spatial testing curves 5 Simulation of jib tank tests by CFD simulation Simulation of jib tank tests used to measure rotational force and the coupling force, the design of testing conditions as shown in Table 2.
Underwater glider research and real-time simulation platform.
Journal of System Simulation,2008,20(22):75-78

This paper presents for the results of such fully coupled simulations.
In this study, commercial software CFDACE was adopted for the simulation.
Table 1 Material properties used in the micropump simulation.
In addition, the simulation can be extended to three dimensions, allowing the analysis of three dimensional flows.
Chen: Proceedings of SPIE Mechatronics, MEMS and Smart Materials (ChongQing, CHINA, September 20-23, 2005)Vol. 6040, P.60400U [6] CFD Research Corporation: CFD-ACE Theory Manual Ver.4.0 (Huntsville, AL 1998)

Turbulent Model In this paper, Menter F.’s SST k-omega turbulent model was used for the numerical simulation[4].
Therefore, SST k-omega model is suitable for the CFD simulation of bluff body with flow separation phenomenon, and then it is suitable for the CFD simulation of the heavy-duty commercial truck.
Numerical Simulation Mesh of Flow Field.
A hybrid of prism and polyhedron mesh was used for the numerical simulation in this research, and the mesh around the body and bridges is refined.
Gu: A Study on the Numerical Simulation of Car Aerodynamic Characteristics Under Crosswind Conditions.

Moreover, based on solving fluid rigid motion equation, turbine self-starting transient numerical simulation is carried out by using CFX CEL language.
What’s more, CFX CEL language is wrote to realize the turbine transient startup state simulation.
As for transient simulation, referring to two peak (10°and 110°) and two valley (50°and 70°) value of CFX simulation in Fig.4, the turbine self-starting performance at different azimuth angles is obtained as shown in Fig.6.It’s obtained that the final angular velocity is stable around 5rad/s at the azimuth angle of 10°, 50°and 70°, and self-starting time at the azimuth angle of 10° is the shortest.
References [1] L.Zhi-Chuan,Z.Liang,Vertical axis trend turbine numerical simulation research, Acta Energiae Solaris Sinica.Vol.32,No.9(2011) 1321-2-1326
[2] W.Shi-Peng,Numerical simulation of wave impact on the trend, PhD Thesis.Dalian: Dalian University of Technology,2007

Keywords: computer modeling, extrusion, melt, simulations; Abstract.
Numerical simulations Geometries and flow conditions.
The simulation is based on the hypothesis that the flow field is fully filled.
Experiments and simulation results show that materials in the flight zones would be molten first, and solid carcass in the middle of flow channel would be molten at last.
Exprimental and CFD investigation on the solidification processing a co-rotating twin screw melt conditioner.

The computational fluid dynamics (CFD) method is implemented for performing the three-dimensional wind turbine using the simulating software tool of FLUNT.
The three-dimensional simulating model is prepared for the computational fluid dynamics (CFD), which is perform by the simulating software tool of FLUENT.
Table 1 Geometrical parameters of NRELS809 series aerofoil Radius (m) Chord length (m) Established angle (°) Radius (m) Chord length (m) Established angle (°) 0.508 0.218 0 2.867 0.574 2.083 0.66 0.218 0 3.172 0.543 1.15 0.884 0.183 0 3.185 0.542 1.115 1.009 0.349 6.7 3.476 0.512 0.494 1.068 0.441 9.9 3.781 0.482 -0.015 1.133 0.544 13.4 4.023 0.457 -0.381 1.258 0.737 20.04 4.086 0.451 -0.475 1.343 0.728 18.07 4.391 0.42 -0.92 1.51 0.711 14.29 4.696 0.389 -1.352 1.648 0.697 11.9 4.78 0.381 -1.469 1.952 0.666 7.979 5 0.358 -1.775 2.257 0.636 5.308 5.305 0.328 -2.191 2.343 0.627 4.715 5.532 0.305 -2.5 2.562 0.605 3.425 　 　 　 CFD Calculation.
All calculations are performed with the simulation of FLUENT using the finite-difference method.
Three-dimensional model is adopted for the wind turbine to perform the CFD calculation using the simulating software tool of FLUENT.