Optimization by Numerical Simulation of the Focusing Properties of Self-Magnetically Insulated Ion Diodes

1991 ◽  
Vol 02 (01) ◽  
pp. 536-540
Author(s):  
THOMAS WESTERMANN
Keyword(s):  
Numerical Simulation ◽  
Computer Simulation ◽  
Power Density ◽  
The Self ◽  
Anode Surface ◽  
Two Dimensional ◽  
Simulation Results ◽  
Focusing Properties

We present two-dimensional electromagnetic computer simulation results performed in order to investigate the focusing properties of self-magnetically insulated ion diodes. It has been shown computationally that in the case of the self-magnetically insulated bθ-diode the power density can be improved by a factor 10 by changing the anode surface.

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.

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.

ACTIVE TRACKING CONTROL OF THE HYPERCHAOTIC LORENZ SYSTEM

2008 ◽  
Vol 22 (19) ◽  
pp. 1859-1865 ◽  
Author(s):  
XINGYUAN WANG ◽  
DAHAI NIU ◽  
MINGJUN WANG
Keyword(s):  
Numerical Simulation ◽  
Tracking Control ◽  
Chaotic Systems ◽  
Lorenz System ◽  
The Self ◽  
Hyperchaotic System ◽  
Reference Signals ◽  
Tracking Controller ◽  
Hyperchaotic Lorenz System ◽  
Simulation Results

A nonlinear active tracking controller for the four-dimensional hyperchaotic Lorenz system is designed in the paper. The controller enables this hyperchaotic system to track all kinds of reference signals, such as the sinusoidal signal. The self-synchronization of the hyperchaotic Lorenz system and the different-structure synchronization with other chaotic systems can also be realized. Numerical simulation results show the effectiveness of the controller.

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.

Computer Simulation of a Transportation Package Impacting Concrete and Soil Targets

2004 ◽  
Author(s):  
S. N. Huang ◽  
S. S. Shiraga ◽  
L. M. Hay
Keyword(s):  
Numerical Simulation ◽  
Computer Simulation ◽  
Impact Test ◽  
Impact Behavior ◽  
Test Results ◽  
Hypothetical Accident ◽  
Simulation Results ◽  
Accident Conditions ◽  
The Impact

This paper compares transportation mockup cask impact test results onto real surfaces with FEA numerical simulation results. The impact test results are from a series of cask impact tests that were conducted by Sandia National Laboratories (Gonzales 1987). The Sandia tests were conducted with a half-scale instrumented cask mockup impacting an essentially unyielding surface, in-situ soil, concrete runways, and concrete highways. The cask numerical simulations with these same surfaces are conducted with ABAQUS/Explicit, Version 5.8, The results are then compared and evaluated to access the viability of using numerical simulation to predict the impact behavior of transportation casks under hypothetical accident conditions.

Effects of surface roughness on self-excited cavitating water jet intensity in the organ-pipe nozzle: Numerical simulations and experimental results

2019 ◽  
Vol 33 (27) ◽  
pp. 1950324
Author(s):  
Xiangdong Han ◽  
Yong Kang ◽  
Deng Li ◽  
Weiguo Zhao
Keyword(s):  
Numerical Simulation ◽  
Surface Roughness ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Energy Intensity ◽  
Volume Fraction ◽  
Water Jet ◽  
The Self ◽  
Simulation Results ◽  
Organ Pipe

This study was conducted to investigate effects of surface roughness on self-excited cavitating water jet intensity in an organ-pipe nozzle. Roughness average (Ra) values are 0.8, 1.6, 3.2, 6.3, 12.5, and 25 [Formula: see text]m, respectively. Numerical simulation results indicate that at inlet pressure of 10 MPa, the maximum, minimum, and real-time pressures in the self-excited oscillation chamber reach their respective peak values. The turbulent kinetic energy intensity in the external flow region is also most intense at this point, the vapor volume fraction in orifice is the highest, the vortex distribution scope in the orifice is the largest under [Formula: see text], and the self-excited cavitating water jet intensity is the strongest. The opposite variations emerge at [Formula: see text] compared to those of [Formula: see text], where the intensity is weakest. Pressure varies only slightly as Ra varies from 0.8 [Formula: see text]m to 6.3 [Formula: see text]m. Turbulent kinetic energy intensity behaves similarly as Ra increases from 0.8 [Formula: see text]m to 3.2 [Formula: see text]m. At [Formula: see text], it was weaker than at Ra = 0.8–3.2 [Formula: see text]m. Similarly, there are only slight differences in vapor volume fraction and vortex distribution scope with Ra from 0.8 [Formula: see text]m to 6.3 [Formula: see text]m. The intensities at Ra = 0.8–3.2 [Formula: see text]m are similar, and weaker at Ra = 6.3 [Formula: see text]m. Pressure values are maximal at inlet pressure of 20 MPa, turbulent kinetic energy intensity is most intense, vapor volume fraction is highest, vortex distribution scope is largest under [Formula: see text] [Formula: see text]m, and intensity is strongest. Distinctions among pressure, turbulent kinetic energy intensity, vapor volume fraction, and vortex distribution scope values with Ra from 0.8 [Formula: see text]m to 3.2 [Formula: see text]m are slight. Differences in the corresponding intensities are also slight; all decrease with Ra from 12.5 [Formula: see text]m to 25 [Formula: see text]m as the intensity gradually weakens. Numerical simulation results were validated by comparison against corresponding experimental phenomena.

The two-dimensional pair correlation function for the Si(001) surface: computer simulation results

1994 ◽  
Vol 6 (6) ◽  
pp. 1083-1088 ◽  
Author(s):  
Jia Zhengming ◽  
Yang Genqing ◽  
Cheng Zhaonian ◽  
Liu Xianghuai ◽  
Zou Shichang
Keyword(s):  
Computer Simulation ◽  
Correlation Function ◽  
Pair Correlation Function ◽  
Pair Correlation ◽  
Two Dimensional ◽  
Simulation Results

Computer simulation of hopping conductivity in lightly doped two-dimensional semiconductors

1988 ◽  
Vol 66 (2) ◽  
pp. 150-154 ◽  
Author(s):  
Mark R. A. Shegelski ◽  
Robert Barrie
Keyword(s):  
Numerical Simulation ◽  
Computer Simulation ◽  
Low Temperature ◽  
Density Of States ◽  
Asymptotic Form ◽  
Two Dimensional ◽  
Resistor Network ◽  
Temperature Range ◽  
Full Form ◽  
The Difference

We present the results of a numerical simulation of a two-dimensional lightly doped compensated semiconductor. We choose a flat density of states with width Δε. We model the semiconductor as a Miller and Abrahams type resistor network; we use the full form of the resistance and do not take the low-temperature asymptotic form because we carry out the simulation at temperatures for which kT is of order Δε. We find that there is a wide temperature range for which [Formula: see text] with ε3 = 0.28Δε. This value of ε3 is considerably smaller than values found by others. We believe that the difference between our result and those of other workers may be attributed to their use of the low-temperature form of the resistance [Formula: see text] in a temperature range in which kT is of order Δε.

Numerical Simulation Study on Self-Settlement Process of High Embankment

2013 ◽  
Vol 671-674 ◽  
pp. 1221-1224
Author(s):  
Yan Zhang ◽  
Yong Wang
Keyword(s):  
Numerical Simulation ◽  
Simulation Study ◽  
Reference Value ◽  
The Self ◽  
Maximum Settlement ◽  
Simulation Results ◽  
Embankment Height

This paper uses the FLAC software to simulate self-settlement of high embankment. Analysis and discussion on the simulation results are performed. The final results indicate that the self-settlement of high embankment can't be ignored, the maximum settlement within the embankment occurs at about （1/3～1/2）embankment height. This conclusion has a reference value for guiding the actual construction.

scholarly journals Numerical simulation of aerodynamic properties of separable elements of space-rocket systems in the LOGOS software package

2021 ◽  
Vol 2099 (1) ◽  
pp. 012072
Author(s):  
S V Aksenov ◽  
D A Korchazhkin ◽  
A Yu Puzan ◽  
O A Puzan
Keyword(s):  
Numerical Simulation ◽  
Computer Simulation ◽  
Software Package ◽  
Reference Data ◽  
Verification And Validation ◽  
Aerodynamic Properties ◽  
Space Rocket ◽  
Simulation Results

Abstract The work describes simulation results of the aerodynamic properties of split elements of the space-rocket systems in the LOGOS software package: the review of the advanced methods for aerodynamic properties has been carried out, the advantages of the computer simulation when solving such problems were demonstrated, verification and validation computations of the simulation problems for the split elements were performed, the produced results were compared with the reference data from available publications. The analysis of the results confirmed the applicability of the LOGOS software package for computing aerodynamic properties of the split elements.

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