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Recently, computational fluid dynamics (CFD) was used as an attempt to predict particle impact velocity for a specific machine and system arrangement.
The time of simulation was 60 ns.
Fig. 4(a)-(b) present the example of the coverage area predicted by CFD [20] and obtained from the shot peening process, respectively.
(a) Coverage area showing impact velocity from CFD[20] (b) Coverage area by shot peening process (c) Surface hardness Fig. 4 Coverage area predicted by CFD [2] (a) and obtained experimentally (b) and surfac hardness at different point in the shot peening area (c) The average residual stress and hardness after shot peening for different pressure are presented in Table 3.
Table 3 Surface hardness and residual stress results after shot peening Pressure (MPa) Surface hardness (HV) Residual stress (MPa) X Y 0.35 553.67 ±45.7 -441.8 ±20.87 -436.6 ±16.86 0.6 542.6 ±87.4 -406.8 ±21.92 -440 ±24.43 Simulation.

The 2-D internal steady flow of the scramjet inlet-isolator was numerically simulated by the CFD method.
The numerical simulation results of two kinds of reasons which make the inlet un-start are obtained.
Abundant of flow simulation and experimental research work of the inlet-isolator has been done at home and abroad.
By experimental data and numerical simulation results to the comparison, using the numerical simulation method can better capture the inlet - shock isolator system structure, indicating consistent with the experimental results.
Two-Dimensional Viscous Simulation of a Inlet-isolator flows at Mach Number 4.

Numerical investigation of pneumatic regulating on low-pressure guide vane Yajie Qina School of Jet Propulsion, Beihang University, Beijing 100191, China a569421550@qq.com Keywords: Variable cycle engine, pneumatic regulation, CFD.
A CFD analysis has been carried out to study the impact of jet parameters (jet position, Angle, flow rate and velocity) to the turbine flow.
The numerical analysis was carried out using the ANSYS CFX-12 CFD package.
Fig. 2 Computational grids of the turbine Fig. 3 The jet pipeline location Performance simulation results The jet position.

Viteazu Street, Timisoara, Romania a*alexandru.rus@raal.ro, bvlad.martian@raal.ro, cmihai.nagi@upt.ro Keywords: heat exchanger, pressure drop, CFD Abstract.
The numerical investigation is performed using Autodesk's Simulation CFD 2014.
Simulations are then performed over the so obtained model geometry.
Simulations are done for six different water flows, ranging from 102 [l/min] to 350 [l/min].
This can be explained by the simplified geometry used for the simulation model and the use of the resistance material.

CFD is a useful tool to study the aerodynamics of vehicle [2-5].
Turbulence models play a key role in CFD.
The turbulence models can be divided into three categories: direct numerical simulation (DNS), large eddy simulation (LES) and Reynolds averaged Navior-Stokes simulation (RANS) [4-5].
A hybrid mesh is adopted for the simulation which mainly is hex-blocks.
Large eddy simulation of rotating decaying turbulence.

Investigation of the Unsteady Flow for the Supersonic Jet Element Yong Xu1, a, Guoqing Zhang1, b and Fei Wang2,c 1School of Aerospace Engineering, Beijing Institute of Technology, Beijing, 100081, China 2 School of Mechanical and Electronic Engineering, Beijing Institute of Technology, Beijing, 100081, China axyxuyong@263.net, bzhangguoqing@bit.edu.cn, cwfphd@126.com Keywords: Supersonic Jet Element; Numerical Simulation; Unsteady Flow; Vortex.
Abstract: The unsteady viscous flow of the supersonic jet element (SJE) was simulated numerically based on CFD technology.
Fig.1 The work mechanism of the SJE Fig.2 Computational grids of the SJE Numerical Simulation Grids Generation.
The computational grid for the numerical simulation is shown as Fig.2.
Gravitational body force and external body forces are ignored, at the same time the wall conditions that include insulation and no sliding are assumed. [2] The model of turbulence is Realizable k-epsilon Model, and enhanced wall treatment that combines a two-layer model with enhanced wall functions is employed.[3] FLUENT (a kind of CFD software) is applied to calculate the unsteady flow, and a dual time-stepping scheme and AMG scheme are employed to solve the unsteady flows in SJE.

A three-dimensional grid and the realizable turbulence model are used in this simulation.
In this paper, a three-dimensional computational fluid dynamics (CFD) model has been developed to simulate the airflow characteristics inside the untwisting chamber of the pneumatic splicer and, based on this model, the principle of yarn untwisting is discussed. 1 Numerical Simulation Figure 1 shows the geometry and dimensions of the computational domain of the pipe.
In this simulation, the Cartesian coordinate system is adopted.
The results of the simulation have confirmed the principle of yarn untwisting proposed by the pneumatic splicer makers.
[3] Zhou Jianheng，Qin Pengfei．The CFD Technology for Pneumatic Splicer Virtual Product Development [J] ．Journal of Donghua University．2004,30(1)：49-52

Numerical simulation of unsteady flow and flow-induced sound of an airfoil and a wing/plate junction are performed in the paper by large eddy simulation (LES) and FW-H acoustic analogy.
It shows that the numerical simulation method in the paper is credible.
In addition, CFD is becoming a more reliable prediction tool for unsteady flow field.
Many CFD analysis rely on DES or LES to correctly simulate the unsteady characteristics in turbulent flow and predict the flow induced sound accurately.
The hybrid CFD/acoustic methods or CAA methods are refined for the acoustic field prediction.

ANSYS as finite element software is used to analyze oil film pressure of hydrodynamic oil film bearing, the stress of bearing bush alloy and the simulation movement of shaft and bearing, and then the reasons of oil film bearing failure and the wear mechanism of bearing bush are illustrated in detail.
CFD model is convenient to establish any type of bearing structure.
An important step of FEM simulation is to discretize the continuous body so as to make the discrete grid be more accurately into a continuous area, and the high-quality discrete grid can ensure the FEM calculating results within error range.
Fig. 1 Distribution of film pressure Fig. 2 Dimensionless load curves Compared with the calculation results of CFD method and Reynolds equation, both results are basically the same, but the former seems slightly higher than that of Reynolds equation.
The dimensionless load curves are basically consistent, which indicates the validity of the CFD method .

In the beginning, fire simulations mostly relied on a zone model approach.
Friedman [1] and Olenick and Carpenter [2] have presented a list of CFD packages that employ this approach.
Britter, CFD Simulations of a Tunnel Fire – Part II, Fire Saf.
Rehm, Large Eddy Simulation of Smoke Movement, Fire Saf.
Baum, CFD Fire Simulation Using Mixture Fraction Combustion and Finite Volume Radiative Heat Transfer, J.