Numerical Simulation of Small-Scale Explosion in Dry Sand

2013 ◽  
Vol 705 ◽  
pp. 110-114
Author(s):  
Yu Qing Ding ◽  
Wen Hui Tang ◽  
Xian Wen Ran ◽  
Xin Xu
Keyword(s):  
Numerical Simulation ◽  
Test Data ◽  
Detonation Product ◽  
Material Model ◽  
Small Scale ◽  
Two Dimensional ◽  
Material Models ◽  
Simulation Results ◽  
Dry Sand ◽  
Sand Material

Numerical simulation of small-scale explosion in dry sand using two sand material models including the Sand model and the LA model were carried out in the present study. Three cases were considered which the depths of burial (DOB) of the explosive C4 charge were 0, 30 mm and 80 mm, respectively. The time arrival of the blast-wave front and the maximum overpressure of fixed measuring locations were studied using a two dimensional axisymmetric model in hydrocode ANSYS/AUTODYN. Furthermore, the crater diameters and the heights of detonation product cloud respect to the time were also studied by comparing with the test data. The simulation results indicate that the both sand material models were hardly predict the test data exactly which proves that the sand properties and the material model should be more carefully studied and defined.

Characteristics of Heat Transfer and Flow on a Surface With Small-Scale Concave Spherical Pits

2008 ◽  
Author(s):  
J. S. Wang ◽  
Y. Qiu ◽  
L. Y. Li
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Small Scale ◽  
Heat Transfer Mechanism ◽  
Transfer Enhancement ◽  
Special Effect ◽  
Turbulent Drag Reduction ◽  
Turbulent Drag ◽  
Simulation Results ◽  
Turbulent Coherent Structure

Small-scale concave spherical pits, which have a special effect on heat transfer enhancement and turbulent drag reduction, are investigated by numerical simulation in detail. Two kinds of small-scale concave pits structures are designed on surface of a plate, which are located in the bottom of a rectangle channel. The characteristics of heat transfer and flow in channel are investigated and compared with a same channel with plate bottom by means of LES. Flow structure and temperature distribution near the pits are analyzed. The numerical simulation results indicate that the concave spherical pits disturb the flow field and vortex is induced by the pits. The turbulent coherent structure is affected by the induced vortex. The numerical simulation indicates that small scale pit can generate the vortex in couple. The range of vortex is accord with the array of small scale pit. The small scale pit can enhance the intensity of vortex. As a result, the temperature field near the pit is changed with generation of the vortex. The heat transfer mechanism on plate with small scale concave spherical pit is summarized.

Influence of Engine Cabin Simplification on Aerodynamic Characteristics of Car

2014 ◽  
Vol 1042 ◽  
pp. 188-193 ◽  
Author(s):  
Xing Jun Hu ◽  
Jing Chang
Keyword(s):  
Numerical Simulation ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
Thin Plates ◽  
Average Thickness ◽  
Two Dimensional ◽  
Engine Cooling ◽  
Aerodynamic Drag Coefficient ◽  
Simulation Results ◽  
The Impact

In order to analyze the impact of engine cabin parts on aerodynamic characteristics, the related parts are divided into three categories except the engine cooling components: front thin plates (average thickness of 2mm), bottom-suspension and interior panels. The aerodynamic drag coefficient (Cd) were obtained upon the combination schemes consisting of the three types of parts by numerical simulation. Results show that Cd by simulation is closer to the test value gained by the wind tunnel experiment when front thin plates were simplified to the two-dimensional interface with zero thickness. The error is only 5.23%. Meanwhile this scheme reduces grid numbers, thus decreasing the calculating time. As the front thin plates can guide the flow, there is no difference on the Cd values gained from the model with or without bottom-suspension or interior panels when the engine cabin contains the front thin plates; while only both bottom-suspension and interior panels are removed, the Cd value can be reduced when the cabin doesn’t contain the front thin plates.

scholarly journals Numerical simulation of mixing by Rayleigh–Taylor and Richtmyer–Meshkov instabilities

1994 ◽  
Vol 12 (4) ◽  
pp. 725-750 ◽  
Author(s):  
D.L. Youngs
Keyword(s):  
Numerical Simulation ◽  
Turbulence Model ◽  
Turbulent Mixing ◽  
Inertial Confinement Fusion ◽  
Three Dimensional ◽  
Small Scale ◽  
Inertial Confinement ◽  
Two Dimensional ◽  
Confinement Fusion ◽  
Icf Target

Rayleigh-Taylor (RT) and Richtmyer–Meshkov (RM) instabilities at the pusher–fuel interface in inertial confinement fusion (ICF) targets may significantly degrade thermonuclear burn. Present-day supercomputers may be used to understand the fundamental instability mechanisms and to model the effect of the ensuing mixing on the performance of the ICF target. Direct three-dimensional numerical simulation is used to investigate turbulent mixing due to RT and RM instability in simple situations. A two-dimensional turbulence model is used to assess the effect of small-scale turbulent mixing in the axisymmetric implosion of an idealized ICF target.

Effects of Materials on Formation of Double-Layered Liners Shaped Charges

2009 ◽  
Vol 79-82 ◽  
pp. 1277-1280
Author(s):  
Yu Zheng ◽  
Xiao Ming Wang ◽  
Wen Bin Li ◽  
Wen Jin Yao
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Numerical Simulations ◽  
Double Layer ◽  
Two Dimensional ◽  
Materials Properties ◽  
X Ray ◽  
Dimensional Finite Element ◽  
Simulation Results ◽  
Good Agreement

In order to study the effects of liner materials on the formation of Shaped Charges with Double Layer Liners (SCDLL) into tandem Explosively Formed Projectile (EFP), the formation mechanism of DLSCL was studied. Utilizing two-dimensional finite element dynamic code AUTODYN, the numerical simulations on the mechanical phenomenon of SCDLL forming into tandem EFP were carried out. X-ray pictures were obtained after Experiments on SCDLL. Comparisons between experimental results and numerical simulation results have good agreement. It can be concluded from the results that the materials properties and configurations of both liners are crucial to the formation of tandem EFP.

Small-scale structure of two-dimensional magnetohydrodynamic turbulence

1979 ◽  
Vol 90 (1) ◽  
pp. 129-143 ◽  
Author(s):  
Steven A. Orszag ◽  
Cha-Mei Tang
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Three Dimensional ◽  
Scale Structure ◽  
Magnetohydrodynamic Flow ◽  
Small Scale ◽  
Two Dimensional ◽  
Magnetohydrodynamic Turbulence ◽  
Hydrodynamic Turbulence ◽  
Small Scale Structure

The formation of singularities in two-dimensional magnetohydrodynamic flow is investigated by direct numerical simulation. It is shown that two-dimensional magnetohydrodynamic turbulence is not as singular as three-dimensional hydrodynamic turbulence (in the sense that it has a less highly excited small-scale structure) but that it is more singular than two-dimensional hydrodynamic turbulence.

Numerical Simulation of Rigid Cylindric Plate's Sinkage on Soil Based on SPH/FEM Method

2014 ◽  
Vol 1049-1050 ◽  
pp. 483-486
Author(s):  
Ting Xia ◽  
Gang He ◽  
Peng Hu ◽  
Xiao Long Li
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Dynamic Simulation ◽  
Smoothed Particle Hydrodynamics ◽  
Mechanical Design ◽  
Material Model ◽  
Fem Method ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Simulation Results

Based on smoothed particle hydrodynamics (SPH) and FEM method, the dynamic simulation of rigid cylindric plate's sinking process on soil is studied with LS-DYNA software, and MAT 147 material model is used to describe soil's attributes. The stress distribution and flowing trend of the soil are compared at different period. The simulation results show that the SPH/FEM method is useful to analyze large deformation of soil, and our findings can give helps to the mechanical design of the components interacting with soil.

scholarly journals Prediction and numerical simulation of residual stress in multi-pass pipe welds

2021 ◽  
Author(s):  
Mahmood Hasan Al-Hafadhi ◽  
Gyorgy Krallics
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Residual Stresses ◽  
Hardness Test ◽  
Element Model ◽  
Good Prediction ◽  
Two Dimensional ◽  
Residual Welding Stress ◽  
Welding Stress ◽  
Simulation Results

AbstractA numerical simulation procedure is presented to predict residual stress states in multi-pass welds in oil transportation pipes. In this paper, a two-dimensional thermo-mechanical finite element model is used to calculate the temperature distribution, hardness, and the distribution of residual stresses during multi-pass welding of pipes of dissimilar metals and varying thicknesses. In this model, the temperature dependence of the thermal and mechanical properties of the material was considered. The present model was validated using the hardness measurement. Good agreement was found between the measurement and the numerical simulation results. The simulated result shows that the two-dimensional model can be effectively used to simulate the hardness test and predict the residual stress in the pipe weld. The simulation results and measurements suggest that the model with moving heat source can obtain a good prediction of residual welding stress. Both the two-dimensional and the three-dimensional modeling can be used to estimate the residual stresses in different weld regions and help saving time.

Two-dimensional numerical simulation of dynamics of small-scale irregularities in the near-Earth plasma

2006 ◽  
Vol 44 (5) ◽  
pp. 398-408 ◽  
Author(s):  
O. V. Mingalev ◽  
I. V. Mingalev ◽  
V. S. Mingalev
Keyword(s):  
Numerical Simulation ◽  
Small Scale ◽  
Two Dimensional

Relationship Between Blast Overpressure and Shell Thickness on the Fluid Pressure on a Cylinder Under Blast Loading

2013 ◽  
Author(s):  
Veera Selvan ◽  
Namas Chandra
Keyword(s):  
Numerical Simulation ◽  
Intracranial Pressure ◽  
Blast Wave ◽  
Shell Thickness ◽  
Fluid Pressure ◽  
Human Head ◽  
Two Dimensional ◽  
Blast Overpressure ◽  
Simulation Results ◽  
Mechanical Insult

The mechanics of blast wave-head interaction determines the magnitude of mechanical insult to the human head during a field explosion and subsequent brain injury. In this work, blast overpressure and shell thickness are related to fluid pressure based on experimental and computational methods. A fluid-filled cylinder is idealized as a two-dimensional analog of a skull-brain complex and is subjected to a Friedlander blast wave. Strain and pressure on the surface of the cylinder and pressure in the fluid (analogue of Intracranial pressure) are experimentally measured and compared with numerical simulation results. The validated numerical model shows that fluid pressure increases linearly with increase in reflected overpressures (ROP) for a given shell thickness. When the ROP is kept constant, fluid pressure increases linearly with the decrease in shell thickness. An equation is developed for predicting the fluid pressure for a given ROP and shell thickness.

Rate-Dependent Constitutive Modeling of Polymer Subjected to Dynamic Loading

2012 ◽  
Vol 185 ◽  
pp. 119-121
Author(s):  
Jian Ming Yuan ◽  
Jan Ma ◽  
Geoffrey E.B. Tan ◽  
Jian Fei Liu
Keyword(s):  
Test Data ◽  
Constitutive Modeling ◽  
Dynamic Compression ◽  
Fem Simulation ◽  
Material Model ◽  
Strain Rates ◽  
Compression Tests ◽  
Material Models ◽  
Rate Dependent ◽  
Tension Tests

This paper proposes an effective and systematical method to obtain reliable rate-dependent material models used in FEM simulation for polymers. Compressive stress-strain curves of two types of polymer are obtained at different strain rates. Rate-dependent elastic-plastic models are applied to describe the observed rate-dependent behaviors, whereby the input data of material model are determined from the test data obtained. Verification of the material models is proposed via comparing FEM simulation with test data of quasi-static tension tests and dynamic compression tests of different strain rates.

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