Physical models and numerical simulation of modern semiconductor lasers

1997 ◽  
Author(s):  
Z-.M. Li
Keyword(s):  
Numerical Simulation ◽  
Semiconductor Lasers ◽  
Physical Models

scholarly journals Experimental and numerical modeling to investigate the riverbank’s stability

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Asad H. Aldefae ◽  
Rusul A. Alkhafaji
Keyword(s):  
Numerical Simulation ◽  
Failure Mechanism ◽  
High Stress ◽  
Physical Models ◽  
Term Condition ◽  
Tigris River ◽  
Soil Settlement ◽  
Failure Angle ◽  
Dangerous Place ◽  
Type Of Failure

AbstractThe purpose of this paper is to assess the failure mechanism of riverbanks due to stream flow experimentally and numerically to avoid recurring landslides by identifying the most dangerous place and treating them by a suitable method. The experiments and the physical models were carried out to study the failure mechanism of riverbank and evaluation of their stability in two cases: short-term condition and long-term condition flow where three models were tested. The Tigris River (Iraq) is considered as a model in this paper in terms of the applied velocity and modeled soil of the banks it was used at the same characteristics in the prototype scale. Also, a numerical simulation was performed using the FLOW-3D program to determine the velocity distribution and to identify the areas subjected to the high stress levels through the water flow. The obtained results in this paper are inspecting of failure mechanism types that occur under the influence of specific limits of flow velocity, which have shown good compatibility with the type of failure in the prototype scale. In addition to calculating the amount of soil erosion, the failure angle, and the amount of soil settlement at the riverbank model is investigated also. The results of experimental work and numerical simulation were well matched, where the standard error rate for Froude number ranged between (1.8%–6.6%), and the flow depth between (2.7%–6.9%).

scholarly journals Numerical Simulation of the Air Cooling System for Scientific Payload Rack on a Space Station

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6145
Author(s):  
Yuan-Yuan Lou ◽  
Ben-Yuan Cai ◽  
Yun-Ze Li ◽  
Jia-Xin Li ◽  
En-Hui Li
Keyword(s):  
Numerical Simulation ◽  
Cooling System ◽  
Space Station ◽  
Thermal Control ◽  
Physical Models ◽  
Air Cooling ◽  
Ansys Fluent ◽  
System A ◽  
Air Cooling System ◽  
Scientific Payload

The space scientific payload rack is a multifunctional experimental platform, and the requirements of the environmental temperature index are different for diversified experimental modules inside. The air cooling system is an important part of the rack thermal control system. A new type of air cooling system with small size and flexible arrangement is proposed in this paper, that is, micro air ducts with pinhole-sized air vents. The rack physical models of new and traditional air cooling modes are established, respectively. The numerical simulation of the inner air flow is carried out by Ansys Fluent CFD software (Ansys Inc., Canonsburg, PA, USA), which verifies that compared with the traditional method, the temperature field and flow field of the new air cooling method are more uniform, and the heat sources located at the edge of the rack can also be cooled better.

Numerical Simulation and Experimental Study of Jet Distance in Abrasive Waterjet Polishing

2012 ◽  
Vol 472-475 ◽  
pp. 2037-2042 ◽  
Author(s):  
Jia Qiang Peng ◽  
Dan Lu Song ◽  
Liang Chao Li
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Theoretical Basis ◽  
Process Research ◽  
Physical Models ◽  
Abrasive Waterjet ◽  
Workpiece Surface ◽  
Cutting Machine ◽  
Simplec Algorithm ◽  
Simulation Results

In this paper, it introduces the work principle of abrasive waterjet polishing (AWJP) and analyzes the jet distance to the influence of the AWJP under a certain pressure, with a numerical simulation and analysis to the jet distance based on jet mechanics and fluid dynamics. By establishing the physical models of the different jet distance of the AWJP and adopting the Realizable k-ε model and the SIMPLEC algorithm, it gains the jet flow field of the AWJP with different jet distance models and the distribution of turbulence intensity and pressure and velocity on the workpiece surface. The numerical simulation results of the different jet distance were analyzed and compared, according to the AWJP to the characteristic requirement of the jet. By doing the polishing experiment with a abrasive waterjet cutting machine, it verifies that the best polishing distance range of AWJP is from 10 times to 13 times of the nozzle diameter, which provides the theoretical basis for the process research of the AWPJ in the future.

Numerical simulation of modal gain in electrically pumped organic semiconductor lasers

2004 ◽  
Author(s):  
Christof Pflumm ◽  
Christian Karnutsch ◽  
Martina Gerken ◽  
Uli Lemmer
Keyword(s):  
Numerical Simulation ◽  
Semiconductor Lasers ◽  
Organic Semiconductor ◽  
Modal Gain ◽  
Electrically Pumped

Numerical Simulation of Heat and Fluid Flow in a Basic Pulse-Tube Refrigerator

2004 ◽  
Author(s):  
Takao Koshimizu ◽  
Hiromi Kubota ◽  
Yasuyuki Takata ◽  
Takehiro Ito
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Heat Exchange ◽  
Surface Heat ◽  
Physical Models ◽  
The Other ◽  
Pulse Tube ◽  
Working Principle ◽  
Pulse Tube Refrigerators ◽  
Heat And Fluid Flow

The working principle of refrigeration in basic pulse-tube refrigerators (BPTR) has been explained by the mechanism called surface heat pumping (SHP) that heat is conveyed from the cold end to the hot end of the pulse tube by the successive heat exchange between the working gas and the wall. In this study, a numerical simulation has been performed to clarify the effect of the wall in BPTRs by comparing the numerical results in two physical models; one is the model considering the heat exchange between the working gas and the wall (HE model), and the other is the model ignoring that (AW model). As a result, the importance in the effect of the wall was shown clearly. In addition, the mechanism of refrigeration other than the SHP was made clear in the AW model.

Research on the Phase Distribution of White Blood Cells with Nucleus Model under VirtualLab Technique

2011 ◽  
Vol 52-54 ◽  
pp. 273-278
Author(s):  
Ya Wei Wang ◽  
Qu Wei Yue ◽  
Min Bu ◽  
Guang Cai Han
Keyword(s):  
Numerical Simulation ◽  
Blood Cells ◽  
Phase Distribution ◽  
White Blood Cells ◽  
Physical Models ◽  
Distribution Analysis ◽  
Biological Cell ◽  
Light Phase ◽  
Simulation Techniques ◽  
Testing Techniques

Focusing on the application technique of the phase testing techniques in cell identification, the analysis to the morphological structures of the leucocytes is done, and the physical models with nucleus of white blood cells are built. Based on the VirtualLab and numerical simulation techniques to systematic study on the distribution of the phase of the the leucocytes, the inside and outside morphological structures of the leucocytes and the main characteristics of the models are found. Thus, the phase testing application has been expanded. The light phase distribution analysis of biological cell is expected to become a new tool to detect the biological cell.

Numerical Simulation of Twin-Parachute Inflation Process for Aircraft Ejection Escape

2020 ◽  
Author(s):  
Liwu Wang ◽  
Mingzhang Tang ◽  
Sijun Zhang
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Numerical Model ◽  
Physical Models ◽  
The Other ◽  
Arbitrary Lagrangian Eulerian ◽  
Safe Distance ◽  
Structure Interaction ◽  
Parachute Inflation ◽  
Good Agreement

Abstract In order to study the safe distance between twin-parachute during their inflation process for fighter ejection escape, the fighter was equipped with two canopies and two seats, two types of parachute were used to numerically simulate their inflation process, respectively. One of them is C-9, the other a slot-parachute (S-P). Their physical models were built, then the meshes inside and around both parachutes were generated for fluid-structure interaction (FSI) simulation. The penalty function and the arbitrary Lagrangian-Eulerian (ALE) method were employed in the FSI simulation. To validate the numerical model for FSI simulation, at first the single parachute of the twin-parachute was used for the FSI simulation, the predicted inflation times for both types of parachute were compared with the experimental data. The computed results are in good agreement with experimental data. As a result, the inflation times were predicted with twin-parachute for both kinds of parachute. On the basis of the locations of ejected seats after the separation of seat and pilot, the initial locations and orientations of twin-parachute were also obtained. The numerical simulations for both kinds of parachute were performed by the FSI method, respectively. Our results illustrate that when the interval time for two seats ejected is greater than 0.25s, two pilots attached the twin-parachute are safe, and the twin-parachute would not interfere each other. Moreover, our results also indicate that the FSI simulation for twin-parachute inflation process is feasible for engineering applications and have a great potential for wide use.

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