scholarly journals Numerical Simulations of Microscale Gas Flows: Continuum Approach

10.5772/7422 ◽  
2009 ◽  
Author(s):  
A. Chaudhuri ◽  
A. Hadjadj ◽  
C. Guha ◽  
T. K.
Keyword(s):  
Numerical Simulations ◽  
Gas Flows ◽  
Continuum Approach

Numerical Simulations of Dynamic Fracture in Thin Pipes

2009 ◽  
Author(s):  
Y. Shie
Keyword(s):  
Numerical Simulations ◽  
Large Deformation ◽  
Dynamic Fracture ◽  
Thin Shell ◽  
Large Scale ◽  
Shell Structures ◽  
Theory Approach ◽  
Continuum Approach ◽  
Ill Conditioning ◽  
High Flexibility

We present a meshless methodology for large scale computations of fractureing thin shell structures subjected to internal pressure loads. The contribution is the first step of an efficient numerical methodology for such kind of events. In this paper, numerical simulations of large deformation dynamic fracture in thin shell structures using 3-D meshfree methods is presented. Due to the smoothness of the meshfree shape functions, they are well suited to simulate large deformation of thin shell structures while avoiding ill-conditioning as well as stiffening in numerical computations. The 3D meshfree representation allows high flexibility since thin structures as well as thick structures can be studied by the same methodology. The meshfree approach makes the methodology more flexible and independent as compared to finite elements, i.e. there is no need for creation of mesh. Dynamic fracture is modeled by a simple criterion, i.e. removing connectivity between adjacent nodes once a fracture criterion is met. The main advantage of such a 3-D meshfree continuum approach is its simplicity in both formulation and implementation as compared to shell theory approach, or degenerated continuum approach. Moreover, it is believed that the accuracy of the computation may increase because of using 3-D exact formulation.

scholarly journals Benchmark numerical simulations of rarefied non-reacting gas flows using an open-source DSMC code

2015 ◽  
Vol 120 ◽  
pp. 140-157 ◽  
Author(s):  
Rodrigo C. Palharini ◽  
Craig White ◽  
Thomas J. Scanlon ◽  
Richard E. Brown ◽  
Matthew K. Borg ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Open Source ◽  
Gas Flows

Numerical simulations of gas flows through an open, non-contact cell for LA-ICP-MS

2011 ◽  
Vol 26 (3) ◽  
pp. 631-634 ◽  
Author(s):  
Dhinesh Asogan ◽  
Barry L. Sharp ◽  
Ciaran J. P. O'Connor ◽  
Damon A. Green ◽  
Jay Wilkins
Keyword(s):  
Numerical Simulations ◽  
Gas Flows ◽  
Icp Ms

scholarly journals Numerical Simulations of Galactic Outflow and Inflow Phenomena

1991 ◽  
Vol 144 ◽  
pp. 407-416
Author(s):  
Kohji Tomisaka
Keyword(s):  
Numerical Simulations ◽  
Galactic Disk ◽  
Gas Flows ◽  
Polar Cap ◽  
Hot Gas ◽  
Numerical Studies ◽  
Dynamical Time ◽  
Density Scale ◽  
Velocity Cloud ◽  
High Velocity Cloud

The recent progress of numerical studies on outflow phenomena from the galactic disk to the halo is summarized. Firstly, a galactic-scale outflow is considered. If the high-velocity cloud is formed from the radiatively cooled gas, which was originally ejected from the disk as a hot gas, the temperature and density at the base of the halo should be ~ 106 K and 10–3 cm–3. Next, recent results of numerical simulations of the evolution of superbubbles, through which hot gas flows out to the halo, are reviewed. In the case of a thin disk whose density scale height is H ≃ 100 pc, the shell begins to be accelerated upwardly after several dynamical time scales. After that, the polar cap of the shell is broken and the hot gas flows away into the halo. In the case of a thick disk (H ≃ 500 pc) or a magnetized disk with a magnetic field parallel to the disk (B ≃ 5μG), the shell is not accelerated and never shows blow-out.

scholarly journals Numerical Studies of Particle-Gas Two-Phase Flowing through Microshock Tubes

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Guang Zhang ◽  
Wei Wei Wang ◽  
Xiang Hui Su ◽  
Xiao Jun Li ◽  
Wen Hao Shen ◽  
...  
Keyword(s):  
Shock Wave ◽  
Drug Delivery ◽  
Shock Waves ◽  
Numerical Simulations ◽  
Free Drug ◽  
Reflected Shock Wave ◽  
Phase Method ◽  
Gas Flows ◽  
Sonic Nozzle ◽  
Reflected Shock

Microshock tubes are always used to induce shock waves and supersonic flows in aerospace and medical engineering fields. A needle-free drug delivery device including a microshock tube and an expanded nozzle is used for delivering solid drug powders through the skin surface without any injectors or pain. Therefore, to improve the performance of needle-free drug delivery devices, it is significantly important to investigate shock waves and particle-gas flows induced by microshock tubes. Even though shock waves and multiphase flows discharged from microshock tubes have been studied for several decades, the characteristics of unsteady particle-gas flows are not well known to date. In the present studies, three microshock tube models were used for numerical simulations. One microshock tube model with closed end was used to observe the reflected shock wave and flow characteristics behind it. The other two models are designed with a supersonic nozzle and a sonic nozzle at the exit of the driven section, respectively, to investigate particle-gas flows induced by different nozzles. Discrete phase method (DPM) was used to simulate unsteady particle-gas flows and the discrete random walk model was chosen to record the unsteady particle tracking. Numerical results were obtained for comparison with those from experimental pressure measurement and particle visualization. Shock wave propagation was observed to agree well with experimental results from numerical simulations. Particles were accelerated at the exit of microshock tube due to the reservoir pressure induced by reflected shock wave. Both sonic and supersonic nozzles were underexpanded at the end of microshock tubes. Particle velocity was calculated to be smaller than gas velocity, which results from larger drag of injected particles.

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