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CFD is a handy tool capable of reasonable predicting of air-flows.
If the shape of building isn’t involved any standards a wind tunnel experiment would be required and here the CFD simulations can provide alternative solution.
There are three turbulent flow simulation methods RANS (Reynolds Averaged Navier-Stokes Simulations), SRS (Scale Resolving Simulations) and DNS (Direct Numerical Simulation) and several commercial and non-commercials software packages offering CFD simulations.
Wilcox, Turbulence Modeling for CFD, third ed., La Canada CA: DCW Industries, Inc., 2006
Menter, Best Practice: Scale-Resolving Simulations in ANSYS CFD, Version 1.0, 2012.

The pedestrian level wind environment including wind comfort and wind safety was assessed with the Computational Fluid Dynamics (CFD) method.
The aerodynamic information of the entire flow field was obtained using CFD software.
By CFD numerical simulation, the ratio (rM) of the measuring point wind speed (Uz) to the standard wind speed in meteorological data (U10) can be obtained.
Process of the assessment of pedestrian level wind environment CFD numerical simulation Geometric model and meshing.
Numerical simulation results of eight typical directions Fig.8.

Four different riser pipe exit configurations were modelled and the flow across them analysed using STAR CCM+ CFD codes.
CFD codes have proven to be a more efficient tool in recent times for simulation of riser design and VIV analyses for risers through CFDs due to its ability to analyse large number of nodes in full-scale simulation [11].
This paper therefore intend to corroborate the present body of knowledge available on the riser design using CFD analysis.
A summary of the physics for the flow simulation in STAR CCM+ is shown in Table 1.
Ogiemudia, Computational Fluid Dynamics (CFD) Simulation in Air Duct Channels Using STAR CCM+.

The Analysis of Aerodynamic Load for High Speed Centrifugal Compressor Blade Zhu Guihua1,a, Qiu Tuanhui1,b and Xie Min2,c 1College of Mechanical and Electrical Engineering,Central South University,Changsha,P.R.china 2Valin Steel,Xiangtan, P.R.china azhuguihuaok@163.com,bqiutuanhui@163.com,cxm54289@sina.com Keywords: Centrifugal Compressor; Blade; Aerodynamic Load; CFD; flow rate Abstract: With the ANSYS Workbench software,the 3D fluid model of the impeller for the centrifugal compressor is set up,whose design flow is 3.2kg/s,rotating speed is 32473r/min,pressure ratio is 3.8,and then with the method of CFD,the k-ε two equations model is selected as the turbulence model,in the condition of design speed,the fluid region of the impeller is simulated under eight different flow rate,the aerodynamic load of the impeller blade and its distribution is acquired under different flow rate,the results showed that the location of the largest aerodynamic load is in the blade that near the outlet
method,then the aerodynamic load is studied. 1 Numerical simulation 1.1 Turbulence model The internal flow of centrifugal compressor is mainly affected by the pressure difference between the inside and outside wall, the centrifugal force of rotation, the curvature of the flow channel; it is a complex three-dimensional flow[5].
to simplify the model,A gap between the vane and the volute value is set to 0 for simulation.The mesh quality directly affect the stability of the numerical simulation of the process,convergence,speed and accuracy.Grid type selected as unstructured grid,Total 123952 nodes and 401204 units,as shown in Fig 2.
Fig 1 The impeller Fig 2 The fluid grid 1.3 Boundary condition Select the boundary conditions of the inlet total pressure and mass flow,the reference pressure is 1 atm,the total temperature and total pressure is given in the importing location,the mass flow is given in the experot location;set periodic boundary condition in the circumferential boundary of the impeller’s upstream and downstream extended aero.Set impermeable,no-slip and adiabatic wall boundary conditions for the solid wall in order to make the mass flux,momentum flux and the energy flux is zero,which is through the grid surface coincides with the solid boundary.The rotation speed is set to be 32473r/min, a temperature of 25℃ air was selected as the fluid medium,the high-level solving mode is selected as the solving format.The calculation convergence criterion is that RMS residual error is less than 1×10-5. 2 The CFD Simulation results and analysis 2.1 Relationship between the aerodynamic loads and
[8] Xie Longhan, Zhao Xinyu,Zhang Jiongming, ANSYS CFX Fluid analysis and simulation, beijing, Publishing House of Electronics Industry. 2012.

FLUENT 14 software was used to carry out the CFD study in a one-phase flow (liquid), as well as in two-phase flow simulations.
Li et al. [8] carried out a comparison between CFD simulations using two different codes, Phonetics and Fluent,, it was found that Fluent is a reliable as code to study the design of the refrigerant distributor and the maldistribution inside it.
CFD simulations were used to evaluate the performance of both existing and altered designs for refrigerant distributors.
Model Comparisons To evaluate the results obtained by CFD to flow in refrigerant distributors, the simulation results from FLUENT were compared with results from FLUENT and PHOENICS obtained by Li et al. [8], [10].
Dorao, "CFD simulation for steam distribution in header and tube assemblies," Chemical engineering research and design, vol. 90 , p. 487–506, 2012. [16] P.

In this study, moving mesh technique is used to construct an outside flow CFD model around H-vertical axis wind turbine with different types of airfoil.
Numerical simulation method Equation.
Number the three blades of CFD model as yepian 1, yepian 2, yepian 3.
[2] Zhiqian Yang, Wenzhuan Cui: Numerical simulation for 2D unsteady flow around the vertical axis wind turbine (Modern Manufacturing Engineering, 2009)
[3] Congxin Yang, Faming Wu, Yuliang Zhang: Numerical simulation on unsteady rotated flow of a vertical axis wind turbine based on moving meshes (TRANSCATIONS OF THE CHINESE SOCIETY FOR AGRCULTURAL MACHINERY, 2009) [4] Ping He, Danmei Hu: The numerical simulation of offshore wind turbine (Renewable Energy Resource, V01.28 No.4 Aug.2010)

The diffuser potential field acting on the impeller has been studied using CFD by [19,20].
Zhao, Numerical simulations of stall inside a centrifugal compressor, Power and Energy IMechE. 221 (2007) Part A: J
Roger, Dougal, Dynamic centrifugal compressor model for system simulation, Journal of Power Sources. 158 (2006) 1333-1343
Flow simulation using control volumes of arbitrary polyhedral shape.
Peck, Validation of unstructured CFD modelling applied to the conjugate heat transfer in turbine blade cooling.

A three-dimensional numerical model was developed based on CFD software FLUENT to simulate leakage process of liquid ammonia tank.
Numerical simulation analyses 3.1 Diffusion characteristics The gas velocity vector on the Z=45m plane at t=10s shows in Fig.3.
Mochida: CFD prediction of gaseous diffusion around a cubic model using a dynamic mixed SGS model based on composite grid technique[J].
[5] Yoshihide Tominaga, Ted Stathopoulos: CFD modeling of pollution dispersion in a street canyon: Comparison between LES and RANS[J].
[8]TAN Wei, LIU Xiao, LIU Yu-jin, et al: Modeling the two-phase cloud evolution from instantaneous flashing release using CFD[J].

Keywords: Helical inlet port, Port deviation, CFD, Flow characteristic Abstract.
Based on the validation of CFD precision by test, the numerical simulation of flow characteristics in ports-valve-cylinder system is carried out.
This paper investigated the influence of inlet port, structure parameters and their deviation on the performance of the port by use of CFD.
The mass flow test results agree well with that of simulation in all valve lift.
Output Contrasts between Simulation and Test Table 1 Contrast of Port Performance Parameter between Test and Simulation Stable flow test Numerical simulation Error Mean swirl ratio 2. 04787 2. 11228 3. 14% Mean flow coefficient 0. 29357 0. 29133 0. 76% Different Versions of Manufacturing Deviation Axial Deviation of Inlet Port The phenomena of axial deviation of inlet port is mainly caused by the sand core floating during casting.

Introduction The past 50 years have seen a revolution in the entire engineering design process as computational simulation has come to play an increasingly dominant part.
CFD simulations of wing shape have been reported [5, 6] in china.
Our numerical simulation model as followed in the figure 4.
The CFD is most important from this aspect, some countries make great effort has led to major advances.
Coakley.1987.Numerical Simulation of Viscous Transonic Airfoil Flows.