Study on Aerodynamic Layout of Two-Dimension Trajectory Correction Projectile

2014 ◽  
Vol 945-949 ◽  
pp. 1619-1622
Author(s):  
Jia Yi Zhang ◽  
Xiao Yu Wang ◽  
Yong Ping Hao ◽  
Yu Yang Guo
Keyword(s):  
Two Dimensional ◽  
Two Dimension ◽  
Flight Stability ◽  
Trajectory Correction ◽  
Simulation Results ◽  
Aerodynamic Simulation ◽  
Ballistic Model

To research aerodynamic layout of the two-dimensional correct projectile, the model of projectile under different aerodynamic layout was established. Various kinds of aerodynamic dates were obtained through aerodynamic simulation. Through the establishment of suitable for two-dimensional modified ballistic model of the projectile, the capability of correcting has been received for the different layouts of the rudder. The simulation results show, to meet the aerodynamic layout of the two-dimensional correct projectile and flight stability, the rudder is closer to the head of the projectile, the correction ability is better.

Design of finite-time guidance law based on observer and head-pursuit theory

2021 ◽  
pp. 095441002098456
Author(s):  
Chenqi Zhu
Keyword(s):  
Finite Time ◽  
Three Dimensional ◽  
Hypersonic Vehicle ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Reaching Law ◽  
Guidance Law ◽  
Fast Power ◽  
Simulation Results ◽  
Guidance Laws

In order to improve the guiding accuracy in intercepting the hypersonic vehicle, this article presents a finite-time guidance law based on the observer and head-pursuit theory. First, based on a two-dimensional model between the interceptor and target, this study applies the fast power reaching law to head-pursuit guidance law so that it can alleviate the chattering phenomenon and ensure the convergence speed. Second, target maneuvers are considered as system disturbances, and the head-pursuit guidance law based on an observer is proposed. Furthermore, this method is extended to a three-dimensional case. Finally, comparative simulation results further verify the superiority of the guidance laws designed in this article.

Direct simulation of evolution and control of three-dimensional instabilities in attachment-line boundary layers

1995 ◽  
Vol 291 ◽  
pp. 369-392 ◽  
Author(s):  
Ronald D. Joslin
Keyword(s):  
Boundary Layer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Plate Boundary ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Computationally Efficient ◽  
Simulation Results ◽  
Dimensional Simulation ◽  
Attachment Line

The spatial evolution of three-dimensional disturbances in an attachment-line boundary layer is computed by direct numerical simulation of the unsteady, incompressible Navier–Stokes equations. Disturbances are introduced into the boundary layer by harmonic sources that involve unsteady suction and blowing through the wall. Various harmonic-source generators are implemented on or near the attachment line, and the disturbance evolutions are compared. Previous two-dimensional simulation results and nonparallel theory are compared with the present results. The three-dimensional simulation results for disturbances with quasi-two-dimensional features indicate growth rates of only a few percent larger than pure two-dimensional results; however, the results are close enough to enable the use of the more computationally efficient, two-dimensional approach. However, true three-dimensional disturbances are more likely in practice and are more stable than two-dimensional disturbances. Disturbances generated off (but near) the attachment line spread both away from and toward the attachment line as they evolve. The evolution pattern is comparable to wave packets in flat-plate boundary-layer flows. Suction stabilizes the quasi-two-dimensional attachment-line instabilities, and blowing destabilizes these instabilities; these results qualitatively agree with the theory. Furthermore, suction stabilizes the disturbances that develop off the attachment line. Clearly, disturbances that are generated near the attachment line can supply energy to attachment-line instabilities, but suction can be used to stabilize these instabilities.

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 modeling of microwave heating

2010 ◽  
Vol 42 (1) ◽  
pp. 99-124 ◽  
Author(s):  
A.K. Shukla ◽  
A. Mondal ◽  
A. Upadhyaya
Keyword(s):  
Thermal Conductivity ◽  
Numerical Modeling ◽  
Temperature Distribution ◽  
Microwave Heating ◽  
Two Dimensional ◽  
Conventional Furnace ◽  
Microwave Furnace ◽  
Simulation Results ◽  
Heating Behavior ◽  
Cylindrical Samples

The present study compares the temperature distribution within cylindrical samples heated in microwave furnace with those achieved in radiatively-heated (conventional) furnace. Using a two-dimensional finite difference approach the thermal profiles were simulated for cylinders of varying radii (0.65, 6.5, and 65 cm) and physical properties. The influence of susceptor-assisted microwave heating was also modeled for the same. The simulation results reveal differences in the heating behavior of samples in microwaves. The efficacy of microwave heating depends on the sample size and its thermal conductivity.

Dual-mode of topological rainbow in gradual photonic heterostructures

2021 ◽  
Author(s):  
Mingxing Li ◽  
Yueke Wang ◽  
Mengjia Lu ◽  
Tian Sang
Keyword(s):  
Finite Element Method ◽  
Finite Element Method Simulation ◽  
Two Dimensional ◽  
Edge States ◽  
Dual Mode ◽  
Strong Robustness ◽  
Mode Excitation ◽  
Simulation Results ◽  
Photonic States ◽  
Sandwiched Structure

Abstract In this letter, a method to realize the topological rainbow trapping is presented, which is composed of gradual ordinary-topological-ordinary heterostructures based on two-dimensional photonic crystals with C-4 symmetry. In the proposed sandwiched structure, the two coupled topological edge states with different frequencies are separated and trapped in different positions, due to group velocity of near to zero. We have achieved the dual-mode of topological rainbow in one structure, which broadens the bandwidth. Besides, the dual-mode of topological rainbow under one mode excitation is also realized by using a simple bend design. The immunity to defects is also investigated and it is found our slowing light system has strong robustness. Finite Element Method simulation results verify our idea, and our work opens up a new way for frequency routing and broadband operation of topological photonic states.

Which aspects of soundscape can the soundscape attributes measure?

2021 ◽  
Vol 263 (5) ◽  
pp. 1940-1944
Author(s):  
Koji Nagahata
Keyword(s):  
Human Perception ◽  
Basic Structure ◽  
Two Dimensional ◽  
Linguistic Structure ◽  
Two Dimension ◽  
Soundscape Studies ◽  
Dimension Space

The eight perceptual attributes for soundscape assessment provided in ISO/TS 12913-2: 2018 are widely used in recent soundscape studies. Several studies across the language showed that the basic structure of the soundscape appraisal two-dimension space obtained from the attributes are robust. However, this robustness of the basic structure only means the robustness of the linguistic structure of the eight perceptual attributes, and never means those attributes cover the whole human perception of the soundscapes. Some studies suggest there are some appraisal scales which cannot be expressed in the two-dimensional appraisal space. This study discusses which aspects of soundscape can the soundscape attributes measure.

An All Optical OR Gate Using BPSK Technique Inside 2D Photonic Crystals

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Bahman Shahmohammadi ◽  
Alireza Andalib
Keyword(s):  
Phase Shift ◽  
Photonic Crystals ◽  
Destructive Interference ◽  
Two Dimensional ◽  
Phase Shift Keying ◽  
All Optical ◽  
Shift Keying ◽  
Working Principle ◽  
Simulation Results ◽  
Or Gate

AbstractIn this paper, we are going to design simulate an all optical OR gate based on two-dimensional photonic crystals. The proposed structure was designed based on phase shift keying technique. The working principle of the proposed structure is based on constructive and destructive interference of optical beams. The simulation results shows that the rise and fall times are 0.8 and 0.2 ps, respectively.

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.

Optimization for Epoxy/Paper Composites Insulated Tubular Bus Structure

2018 ◽  
Vol 922 ◽  
pp. 169-174 ◽  
Author(s):  
Peng Hu Li ◽  
Ling Ruan ◽  
Cheng Lei Li ◽  
Fan Yang ◽  
Hai Yun Jin ◽  
...  
Keyword(s):  
Structural Design ◽  
Initial Structure ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Insulation Materials ◽  
Copper Pipe ◽  
Two Dimensional Model ◽  
Bus Structure ◽  
Simulation Results ◽  
Paper Composites

Uniform standard in the structural design for insulated tubular bus is not available both at China and abroad, and there are few reports about insulated tubular bus, which causes a waste of resources and even leads to grid failure. In this paper, epoxy/paper composites insulated tubular bus was investigated and a two-dimensional model was preferred in the simulation due to the axial symmetry of insulated tubular bus. The distribution of electric field and temperature in composite insulated materials were studied with the changes of the diameter/thickness of copper pipe and the thickness of insulation materials. According to the results simulation results, the structure of insulated tubular bus was optimized, the thickness of copper pipe conductor and insulation had been greatly reduced. Compared to the non-optimized initial structure, the amount of copper pipe conductor used for the optimized insulated tubular bus was reduced by 48%, the amount of insulation materials were reduced by 52.5%, and the current density of copper pipe conductor increased by 92.2%.

Efficient Optical Localization for Mobile Robots via Kalman Filtering-Based Location Prediction

2016 ◽  
Author(s):  
Jason N. Greenberg ◽  
Xiaobo Tan
Keyword(s):  
Kalman Filter ◽  
Kalman Filtering ◽  
Mobile Agent ◽  
Optical Communication ◽  
Line Of Sight ◽  
Location Prediction ◽  
Two Dimensional ◽  
Optical Communication System ◽  
Search Range ◽  
Simulation Results

Localization and communication are both essential functionalities of any practical mobile sensor network. Achieving both capabilities through a single Simultaneous Localization And Communication (SLAC) would greatly reduce the complexity of system implementation. In this paper a technique for localizing a mobile agent using the line of sight (LOS) detection of an LED-based optical communication system is proposed. Specifically, in a two-dimensional (2D) setting, the lines of sight between a mobile robot and two base nodes enable the latter to acquire bearing information of the robot and compute its location. However, due to the mobile nature of the robot, establishing its LOS with the base nodes would require extensive scan for all parties, severely limiting the temporal resolution and spatial precision of the localization. We propose the use of a Kalman filter to predict the position of the robot based on past localization results, which allows the nodes to significantly reduce the search range in establishing LOS. Simulation results and preliminary experimental results are presented to illustrate and support the proposed approach.

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