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The flow simulation emulated the Cedval A1-1 single-building experiment and the concentration distribution for two scenarios was synthetically produced by simulation.
When pollutant releases occur over urban sites Computational Fluid Dynamics (CFD) is usually applied to solve the dispersion model.
CFD can naturally include complicated boundary geometries, initial conditions, chemical reactions, deposition processes, etc.
The model implementation is performed within the CFD commercial software Ansys Fluent.
The flow simulation emulates the Cedval A1-1 single building experiment [7].

The simulation analysis results were tested on a real machine for validation in order to identify the reliability of the simulation.
This study adopted 3D CFD software, and combined the finite volume method, SIMPLE algorithm, and first order upwind difference method for numerical analysis.
Thus, the 180943 mesh was used for this simulation in order to maintain the accuracy and reduce simulation time.
The CFD simulation analysis and the prediction analysis results of the atomization flow field were used for comparison and validation through actual tests, so as to build a reliable computer simulation analysis model for the ultrasonic atomization spray coating process.
E., “REFLEQS-2D: A Computer Program for Turbulent Flows With and Without Chemical Reaction, Volume 2: Validation Manual,” GR-88-4, CFD Research Corporation, Huntsville, AL (1989)

The result is proved by CFD software.
Numerical simulation 4.1 Governing equation Continuity equation of incompressible fluid and RANS equation.
Figures below are the results of simulation.Fig.8 , fig.10 and fig.12 are the resistance coefficient , moment coefficient and lift coefficient in the astern maneuverability.
The model is much more stable in the straight maneuverability. 4.3 Results and Discussion Through the experiment and simulation , the resistance,lift force and moment of astern maneuverability and upright maneuverability are compared , the results show big difference.
And simulation will use the technology of dynamic mesh technique to text the moving model.

Simulation program ANSYS.
There is a new way based on computer simulation.
In my case, the simulation program ANSYS based upon variation method of finite elements supported by FLOTRAN CFD module has been used for this method.
In ANSYS system there are two basic elements for FLORTAN – CFD.
Using the element in FLORTAN – CFD the calculation for fluctuant and thermal distribution through area of elements forming the network is carried out.

CFD simulation of the liquid-column flow field of double contact Lijun Fang1, a, Yanchao Chang2,b 11School of Energy Power and Mechanical Engineering,North China Electric Power University, Baoding 071003,China afanglijun2009@163.com, bchangyanchao12345@163.com Key words: double contact ; liauid-column tower; flow field; pressure drop.
Through the numerical simulation of the particular condition, gas flow condition was described in conditions of different nozzle number and different liquid air ratio.
Guo Ruitang[1] went on numerical simulation of flow distribution in the wet FGD impinge liquid-tower and the SO2 absorption, using CFD software Fluent and non-steady-state mass transfer reaction theory .
The situation of the liquid flow is described under the conditions of different number of nozzles in the tower and different liquid to gas ratio, through numerical simulation of specific conditions.
Mathematical model Simulation of air flow field RNG two-equation model [5] is proposed by Yakhot and Orzag.

However, there was limited research using a CFD tool to predict the flow pattern and develop the flow pattern maps.
Properties of gas and liquid used in simulations.
(a) The computational mesh used in the simulations.
The simulations are performed in commercial CFD solver ANSYS Fluent and the simulations are run in a transient mode.
Therefore, the study also shows that CFD method is a feasible way to draw the two-phase flow patterns map.

Three new shapes of hull bow design for the multipurpose amphibious vehicle were conducted at several speeds to investigate the hydrodynamic phenomena using Computational Fluid Dynamics (CFD, RANS code), which is applied by Ansys-CFX14.0 and Maxsurf.
This research would be done via CFD (ANSYS-CFX 14.0) and analyzed the hydrodynamic resistance.
A significant number of applications of computational fluid dynamics (CFD) tools to hydrodynamic optimization, mostly for reducing calm-water drag and wave patterns, demonstrate a growing interest in optimization.
Pressure drag (i.e., form resistance) and wave resistance are frequently optimized using Computational Fluid Dynamics (CFD) but the total wetted surface remains a given.
CFD will play an important role in determining these causes by providing a detailed understanding of the physical phenomena.

By changing its speed can still achieve the transfer of energy and then generate electricity,although blade is short, and the wind area is reduced.In the study of the blade,high quality grid is the key.This paper discusses the fan blade meshing used ICEM CFD in the rotation of the basin.
Fig.1 The simple figure of scenery tower power generation device. 1.Model Building Using UG software to build the blade model.The fan blade rotation speed is faster, gas particle flow is more complex, so the meshing of flow field directly affect the results of the accuracy of the flow field numerical simulation.
(1) After putting the model into ICEM CFD, name its boundary,the model as shown in figure 3.
As shown in figure 4,5,fluid in the blade surface speed streamline is more well-distributed, calculating the residual curve also gets the convergence, its convergence precision is up to 1e-04(as shown in figure 6),explaining the grid quality is better, that has already reached the simulation requirements.
Fig.6 Residual figure. 4.Summary According to this model,Robust (Octree) method of five methods in ICEM CFD meshing is the best grid generation method,for more complex geometry it can also generate a better quality of the grid.Setting up necessary boundary layer grid to the overall quality of the grid has very great help,and widening the margin of the blades to help reduce the number of grid, so as to further simulation analysis of model lays a foundation.

Design of impeller of centrifugal compressor for water-air engine Yun Wang1, a , Wei Zhang 1, b 1Department of Nanchang Hangkong University aircraft engineering institute, Nanchang 330063, China a wangyun66@163.com, b zhangwei19870923@163.com Keywords: air-water engine, impellor of centrifugal compressor, CFD.
With 3D design and a 3D CFD solver on it and analysis the results of numerical simulation.
Based on the studies of domestic and foreign aeroengine compressor and centrifugal water pump, this paper aims at the water-air engine, makes an aerodynamic design and research on the engine compressor impeller, and with the application of fluent software makes a numerical simulation of air and water model, according to whose results conduct an analysis and evaluation of the designed centrifugal impeller[2-3].
It can be seen from the results of numerical simulation and post-processing curve, that water-air impeller changes from the original conventional impeller to compound one with compressor and pump taken into account, which meet certain performance requirement.
[4] Tong Yueping, Zhang Shujia and Li Xianhua: Comparison of standard k-ε model and RSM model in 3D simulation in centrifugal pump (2008).

Liu and Kawachi [15, 16] used the CFD method to simulate 2D and 3D dimensional hydrodynamics of Tadpole locomotion.
Fluid loads in structural applications and structural deformation in CFD analysis are considered in FSI.
The displaced shape from CSD is further coupled with computational fluid dynamics (CFD), from which new loadings are determined.
Fig. 4 shows CFX simulation model with defined boundary conditions (BC).
Dynamic analysis of the fluid, surrounding the assembly, is conducted by CFD.