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Blast Wave Mitigation from the Straight Tube by Using Water Part II - Numerical Simulation Yuta Sugiyama1,a*, Tomotaka Homae2,b, Kunihiko Wakabayashi1,c, Tomoharu Matsumura1,d and Yoshio Nakayama1,e 1National Institute of Advanced Industrial Science and Technology, Central 5, Higashi 1-1-1, Tsukuba, Ibaraki, Japan 2National Institute of Technology, Toyama College, 1-2 Ebie-neriya, Imizu, Toyama, Japan ayuta.sugiyama@aist.go.jp, bhomae@nc-toyama.ac.jp, ck-wakabayashi@aist.go.jp, dt-matsumura@aist.go.jp, ey-nakayama@aist.go.jp Keywords: Mitigation, Blast wave, Water, Energy exchange, CFD Abstract.
Numerical simulations are used to assess the effect of water that is put inside the tube.
Because detailed data on the explosion phenomenon are required to clarify the mitigation mechanism, a numerical simulation would be a useful tool.
Cylindrical high explosive (H.E.) is located near the end wall In numerical simulations of explosions and blast-wave propagation, the grid resolution is often determined by the number of grid points in a scaled distance Z [m/kg1/3].
Lines and symbols denote data of the present simulations and the previous experiments [7], respectively.

In this sense, this paper aims to thermally characterize the polymer (epoxy resin) composite reinforced with NiTi SMA wires through numerical simulation using the ANSYS CFX software.
The representation of the computational domain was done with the aid of ICEM-CFD 12.1 through points, curves and surfaces (Figure 2).
(a) (b) (c) Figure 4 - Representation of the hexahedral mesh generated by ICEM-CFD (a) front view, (b) details of the wire region and (c) 3D view of the sample.
In the Ansys CFX software (ICEM-CFD), this subdomain must be specified in mesh generation.
Because the function type used in the experiments (triangular type), the electric current use in the numerical simulation is defined by two functions, as follows: ; s; (9) 194s

The simulations were performed using FLOW-3D AM.
This simulation integrates the Discrete Element Method (DEM) with Computational Fluid Dynamics (CFD) model.
Numerical Configuration, Process Parameters and Case Simulations.
The numerical simulation of the effects of different types and sequences of scanning strategies on molten pool dynamics, and surface quality in the SLM process of Ti-6Al-4V was conducted using Flow-3D AM, which integrates the Discrete Element Method (DEM) with Computational Fluid Dynamics (CFD) modeling.
Ra values were measured based on simulation results across five tracks at the scanning length of 500 µm.

Simulation and analysis of steady and 2D flow field by using ANSYS8.0 and getting the press and velocity contour. omulate the leakage. then through comparison and analysis offering theory evidence for controlling leakage effectively.
Therefore domestic and foreign scholars have done a lot of work in this: literature[1] uses the CFD software to built the numerical simulation on one dimensional flow; literature[3] proposed the dynamic characteristics expression and the calculation method of the element method; literature[4] use of fluid software to built the numerical simulation on fluid flow field and temperature field for mechanical seal cavity.
Numerical Simulation of Flow in Convergent Wedgelike Gap.Lubrication Engineering, 2004.3(163):47-49( In Chinese)

Numerical Simulation of Fluid Flow in a New High efficient Mixer Qing Wu, Yachen Zhang, Xuejun Liu, Baoan Han School of Material and Mechanical Engineering, Beijing Technology and Business University, Beijing 100048, China Email: wuqing@th.btbu.edu.cn; allld2000@yahoo.com.cn ;xj007@yahoo.com;646333407@qq.com Keywords: high efficient mixer, spiral blade, rotating impellor, flow field, numerical simulation Abstract.
In order to determine proper structural parameters of the new high efficient mixer created by the author, the CFD software is applied to simulate numerically three dimensional incompressible turbulent fields for three static mixing units and the mixing unit with rotating impellor.
Numerical Simulation and Analysis Governing Equations Because the fluid flow is characterized with eddy and fluctuation, the turbulent kinetic energy transport model and Reynolds stress model are used to describe the flow state.
The simulation by fluent software is performed to obtain the velocity contour of rotating impellor following single-blade spiral blade (Fig.12) and that of impellor following three-blade spiral blade (Fig.13), which can show the flow state of fluids inside the impellor.
(3) Because of complexity of flow state in the mixer, in addition to simulation and analysis by fluent software for providing some theoretical basis, it is necessary to perform verification by experiments to optimize the structural parameters.

The model simulates operation with and without gas injection and it is developed in the commercial PHOENICS 3.4 CFD code in order to solve all conservation equations governing the process, i.e., continuity, 3D turbulent Navier-Stokes and k-ε turbulence model for a two-phase fluid flow problem using the Inter Phase Slip Algorithm.
Lane et al. [9] developed a model under an Eulerian frame of reference in a CFD code to predict mixing in a ladle equipped with a rotating impeller and a baffle.
The impeller has four nozzles positioned at equal distances from one to the other, making possible to consider only one fourth of the entire ladle as a computational domain for the simulations.
To run the simulations, a PC with a Pentium IV® processor was employed, and each simulation took about five hours to get convergent results.
Simulations without gas purging under standard conditions (a) Flow patterns.

Flow parallel to flat plate had been studied by former researchers with its theory and numerical simulation were quite complete.
The numerical simulation of drag coefficient at high angle of attack based on CFD (Computational Fluid Dynamic) became more and more reliable with the advanced performance of computer though there were still some deviations.
Numerical simulation of two dimensional flow about a normal flat plate based on CFD was carried out by Lisoski[3], whose results had been compared with experiment data, and also the reasons why where were deviations were illustrated.
Flow around a flat plate with Reynolds number of 2×104 and angle of attack of 18°was simulated by Breuer[4] with detached eddy simulation (DES), Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES), the lift and drag coefficients and Strouhal numbers simulated by above methods was compared, the unsteady RANS method of Spalart-Allmaras model could not be able to predict the characteristics of separated flow, while the DES and LES approach reasonably yielded shedding phenomenon and some integral parameters.
Numerical Simulation Method Governing equations.

In addition, Gabriel Salanta[7] published a study on the effect of entirely urea SCR system layout to urea-related deposits by CFD analysis and test.
CFD result for the injection atomization To ensure urea to atomize and decompose sufficiently, the diameter of the down-stream pipe should satisfy the atomization space for the urea, and the distance from injection point to opposite pipe wall should be larger than the penetration distance of the urea spray.
The result of CFD simulation about the integrated injector mountings is given in Figure 8.

Analysis of Thermal Airflow Process of the Annular Cooler Simulation Assumption.
Simulation Process.
(3) Settings of Fluent simulation parameter.
(4) Simulation result.
Wang: Principle and Application of CFD software (Tsinghua University Press 2004).

This study uses FLOW-3D CAST simulations to analyze heat transfer and solidification behavior in two copper mold designs.
The simulations evaluate flow uniformity, thermal dissipation, and cooling rate distribution, aiming to correlate cooling rate with achievable BMG diameter.
To bridge this gap, the present study employs FLOW-3D CAST, a commercial CFD-based casting simulation software, to model mold filling and solidification in two copper mold designs.
The simulation domain is discretized using a finite difference method (FDM) into a single mesh block.
The simulation employs approximately 3.1 million voxels with an optimal mesh size of 1 mm.