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CFD Simulation of Natural Draught Cooling Tower Wind-Covering Masoud Darbandi1,a, Hossein Salemkar1,b, Ali Behrouzifar1,c, Bagher Abrar1,d 1Department of Aerospace Engineering, Sharif University of Technology, Tehran, Iran adarbandi@sharif.edu, bsalemkar@mehr.sharif.edu, cbehrouzifar@ae.sharif.edu, dbagher_abrar@ae.sharif.edu Key words: Natural draught cooling tower- Industrial chimney- Wind covering effect- CFD Abstract.
Meroney [4] also utilized CFD and elaborated some more points on the wind covering effects.
Cooling tower modeling and simulations To start the computational fluid dynamics simulation, we should construct a cooling tower model.
Behnia: The performance of natural draft dry cooling towers under crosswind: CFD study.
Meroney: CFD Prediction of Cooling Tower Drift Prepared.

University of Feres Yahia, Medea, Algeria aboualemlaribi@yahoo.com, blmp2m_cum@yahoo.fr Keywords: Turbulence, CFD, flow meter, flow conditioner, Navier-Stokes, k-ε.
For the simulation, code CFD Fluent was used.
The numerical analysis is conducted by the CFD Fluent code [7].which is based on the resolution of the Navier-Stokes equations with k-ε like turbulence model.
Experimental Facility for the Simulation Our installation, Fig. 1, consists of an inlet pipe length 10D, followed by disturbers 90° double bend, or a valve, or a Tee, Fig. 2.
The effectiveness of CFD code Fluent to predict flow development in different installations is done where good predictions are presented.

The "CFD" is used to determine the pressure, temperature and velocity fields in the lubricant film, the stress intensity and displacement field is obtained by "FSI" simulation.
Thus, a parametric study on the one hand it makes the calculation of the fields of pressure and temperature in the lubricant film "CFD".
Using one hand, the numerical simulation Computational Fluid Dynamics "CFD", this allowed us to determine the pressure field and temperature in the lubricant film.
Journal of Tribology International 44 380-395 [4] Shenoy B.S., Pai R.S., Rao D.S. and Pai R. 2009 “Elasto-hydrodynamic lubrication analysis of full 360° journal bearing using CFD and FSI techniques”, World journal of modeling and simulation, 5, pp. 315-320 [5] Wang Y, Zhang C, Liu G.
Vienne, Autriche 3-7 September [6] Ouadoud A., Boutammachte N. and Mouchtachi A. 2011 “Numerical simulation CFD, FSI of a hydrodynamic journal bearing”, Journal of Advanced Research in Mechanical Engineering (JARME).

A 2D CFD numerical method based on loose coupling algorithms was adopted to simulate vortex induce vibration of a spring-mounted cylinder.
Obviously, two-dimensional numerical simulation is the basis of "strip theory approach".
Much of the numerical errors mainly result from aspects of the problem solution, such as the procedure of iteration, the grids and time step size in most CFD simulation cases.
The hydrodynamics in each sub-step of CFD calculation can be worked out by the integral form of the surface force passed to the rigid body motions.
A 2D CFD numerical method based on loose coupling algorithms was adopted to simulate vortex induce vibration of a spring-mounted cylinder.

Fluent is one of the comercial CFD softwares used widely.
It is common that CFD simulation results and the building regulations are combined to assess the built wind environment.
Blocken and Persoon [5] have combined the CFD simulation results and the the Netherland building regulation to assess the wind pedestrian comfort around a large football stadium in Amsterdam.
The CFD simulation results are affected by many issues such as wind direction,velocity,building location,building shape,building material etc.[8-10].
Pedestrian wind comfort around a large football stadium in an urban environment: CFD simulation, validation and application of the new Dutch wind nuisance standard.

It is verified that this method is valid to mesh molding and CFD experiment.
Support Software of CFD-Modeling We could gain the numerical solutions of the governing equations representing the flow field by the method of CFD.
The numerical experiments of flow field are based on the mathematic models that include of 3 D physical model, grid model and CFD model.
Grid model of the flow field for the control valve The grid model in not only a geometric representation of CFD model but also is the support simulation and analysis.
(In Chinese) [5] Zaizhong Han : Simulation Examples and Application of FLUENT (Beijing Institute of Tech- nology Press, Beijing 2005).

The effect of the length of mesh pipe on ventilation effect was studied by numerical simulation.
It is important and difficult of model building and settling to study the temperature variation field of storage grain, and computational fluid dynamic (CFD) method is a good way to settle these problems, which have the characteristics of short research cycle, efficient simulation and low cost [4].
CFD technology was already applied for air conditioner, drying, ventilation and transportation and other relevant field [5].
Therefore, compared with experiments, comprehensive results can be obtained by CFD simulation.
Result and discussion Three design projects were adopted in simulation study.

Computational fluid dynamics (CFD) is an important applied research area of scientific computation visualization.
Aiming at the difficult for three-dimensional display in the post-processing of wrap-around fins’ flowfield with commercial CFD software, the visualization techniques of CFD were investigated.
But when applying in the visualization of CFD computational data, it becomes very fussy and has bad repeatability.
The important characteristic of CFD software is mighty repeatability, so this operate mode does not fit for the visualization of CFD computational data.
In the course of numerical simulation, computational results of pressure, temperature and so on status parameters were obtained from FLUENT with UDF program, and saved as *.dat file.

This paper carries out numerical simulation of three-dimensional flow field in mixing process by the compute fluid dynamics (CFD) software FLUENT, uses the multi-reference frame and standard k-ε turbulence model to simulate the density in three different conditions.
In this research the analysis is realized by numerical simulation: Numerical Simulation Model The stirring tank is feature with following characteristics.
Simulation Result The velocity of the impeller is 150rpm, according to real working conditions, three different conditions are analyzed as follows[5][6]: Working Condition One (sand-water ratio 20%) Fluid inlet velocity is 5.48m/s, sand input velocity is 0.2m/s.
Acknowledgments This work is supported by National High Technology Research and Development Program (Project Code: 2009AA063601) Reference [1] Hanchuan Wu and Wenjin Gao: Petroleum Machinery.Vol. 31 (2003), No.s1, p. 63-65 [2] Weetman RJ: Automated Sliding Mesh CFD Computations for Fluidfoil Impellers, Proceedings of 9th European Conference on Mixing, Paris, (1997), p. 195-202 [3] Han Zhanzhong, Wang Jin, Lan Xiaoping: Examples and Applications of Fluid Simulation Based on FLUENT, Beijing Institute of Technology Press, (2006) [4] Wang Junfu: Computational Fluid Dynamics Analysis – CFD Software Theory and Application, Tsinghua University Press, (2004) [5] Dong L, Johansen S T, Engh T A.: Flow Induced by an Impeller in an Unbaffled Tank-II, Numerical Modelling, Chem.
Sci., 49, p. 3511-3518 [6] Murthy J Y,Mathur S R,Choudhury D. : CFD Simulation of Flows in Stirred Tank Reactors Using a Sliding Mesh Technique.

Large Eddy Simulation of Aerodynamic Forces on a Bridge Pylon Xuyong Yinga, Fuyou Xub, Zhe Zhang and Yonggang Tan Faculty of Infrastructure Engineering, Dalian University of Technology, China ayingxuyong@sina.cn, bfuyouxu@hotmail.com Key words: Large eddy simulation (LES), Aerodynamic force, Pylon, Computational fluid dynamic (CFD), Reynolds averaged Navier-Stokes equations (RANS) Abstract.
Accurate prediction of wind loads on such structures using computational fluid dynamics (CFD) is becoming increasing significant.
The techniques of CFD, such as large eddy simulation (LES), Reynolds averaged Navier-Stokes equations (RANS) model etc., have been widely used in wind engineering.
Thus, the results of the numerical simulation can be considered reliable.
From the present study, it is believed that the CFD simulation applying LES turbulence model can be successfully applied to the prediction of wind loads on a bridge pylon, whose wind tunnel tests are expensive.