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Journal articles on the topic 'DSMC'

Author: Grafiati

Published: 4 June 2021

Last updated: 14 March 2023

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1

Zhao, Di, and Haiwu He. "DSMC: Fast direct simulation Monte Carlo solver for the Boltzmann equation by Multi-Chain Markov Chain and multicore programming." International Journal of Modeling, Simulation, and Scientific Computing 07, no. 02 (June 2016): 1650009. http://dx.doi.org/10.1142/s1793962316500094.

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Direct Simulation Monte Carlo (DSMC) solves the Boltzmann equation with large Knudsen number. The Boltzmann equation generally consists of three terms: the force term, the diffusion term and the collision term. While the first two terms of the Boltzmann equation can be discretized by numerical methods such as the finite volume method, the third term can be approximated by DSMC, and DSMC simulates the physical behaviors of gas molecules. However, because of the low sampling efficiency of Monte Carlo Simulation in DSMC, this part usually occupies large portion of computational costs to solve the Boltzmann equation. In this paper, by Markov Chain Monte Carlo (MCMC) and multicore programming, we develop Direct Simulation Multi-Chain Markov Chain Monte Carlo (DSMC3): a fast solver to calculate the numerical solution for the Boltzmann equation. Computational results show that DSMC3 is significantly faster than the conventional method DSMC.

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Karthikeyan, Viji, Anil Kumar Tiwari, Agalya Vedi, and Buvana Devaraju. "Input-output linearization of DC-DC converter with discrete sliding mode fuzzy control strategy." International Journal of Electrical and Computer Engineering (IJECE) 12, no. 2 (April 1, 2022): 1223. http://dx.doi.org/10.11591/ijece.v12i2.pp1223-1232.

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The major thrust of the paper is on designing a fuzzy logic approach has been combined with a well-known robust technique discrete sliding mode control (DSMC) to develop a new strategy for discrete sliding mode fuzzy control (DSMFC) in direct current (DC-DC) converter. Proposed scheme requires human expertise in the design of the rule base and is inherently stable. It also overcomes the limitation of DSMC, which requires bounds of uncertainty to be known for development of a DSMC control law. The scheme is also applicable to higher order systems unlike model following fuzzy control, where formation of rule base becomes difficult with rise in number of error and error derivative inputs. In this paper the linearization of input-output performance is carried out by the DSMFC algorithm for boost converter. The DSMFC strategy minimizes the chattering problem faced by the DSMC. The simulated performance of a discrete sliding mode fuzzy controller is studied and the results are investigated.

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3

Luo, Le, and Ming-Zhong Yang. "Switching Power Supply Control Strategy Based on Monitoring Configuration." Journal of Nanoelectronics and Optoelectronics 16, no. 5 (May 1, 2021): 766–72. http://dx.doi.org/10.1166/jno.2021.2993.

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In this paper, a new discrete-time sliding mode predictive control (DSMPC) strategy with a PID sliding function is proposed for synchronous DC-DC Buck converter. The model predictive control, along with digital sliding mode control (DSMC) is able to further reducing the chattering phenomenon, steady-state error, overshoot, and undershoot of the converter output voltage. The proposed control method implementation only requires output error voltage evaluation. The effectiveness of the proposed DSMPC is proved through simulation results executed by the MATLAB/SIMULINK software. These results demonstrate its performance is superior to DSMC. The selected synchronous Buck converter in this paper has 380 V input voltage and 48 V output voltage that can be applied in sections of DC distribution systems.

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4

Olson, Spencer E., and Andrew J. Christlieb. "Gridless DSMC." Journal of Computational Physics 227, no. 17 (September 2008): 8035–64. http://dx.doi.org/10.1016/j.jcp.2008.04.038.

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5

DE SOCIO, L. M., and L. MARINO. "SIMULATION AND MODELLING OF FLOWS BETWEEN ROTATING CYLINDERS." Mathematical Models and Methods in Applied Sciences 10, no. 01 (February 2000): 73–83. http://dx.doi.org/10.1142/s0218202500000069.

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The equations which govern a number of models for flows between rotating cylinders at different Knudsen numbers are solved numerically by means of the direct simulation Monte Carlo method (DSMCM) to show their limitations. The DSMC code was firstly tested and validated against existing experimental data and then its results represented the reference data base for evaluating the characteristics of each model.

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Zhang, Qing-Wei, La-Mei Teng, Xin-Tian Zhang, Jing-Jing Zhang, Ying Zhou, Zhi-Rui Zhou, Yi-Chao Hou, Zhi-Zheng Ge, and Xiao-Bo Li. "Narrow-band imaging in the diagnosis of deep submucosal colorectal cancers: a systematic review and meta-analysis." Endoscopy 49, no. 06 (May 4, 2017): 564–80. http://dx.doi.org/10.1055/s-0043-103014.

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Abstract Background and aims Magnifying endoscopy with narrow-band imaging (M-NBI) has been widely used in the differential diagnosis of deep submucosal colorectal cancers (dSMCs) from superficial submucosal cancers (sSMCs) and intramucosal neoplasms. We aimed to pool the diagnostic efficacy of M-NBI and compare it with that of magnifying chromoendoscopy (M-CE) in diagnosing colorectal dSMC. Methods PubMed, EMBASE, and the Cochrane Library were searched to identify eligible studies. Meeting abstracts were also searched. A bivariate mixed-effects binary regression model was used in the meta-analysis to calculate the pooled diagnostic efficacy of M-NBI and compare it with that of M-CE in the diagnosis of dSMC. Subgroup analyses and meta-regression were conducted to explore sources of heterogeneity. Results We included 17 studies: 14 full texts and 3 meeting abstracts. The pooled sensitivity, specificity, and area under the summary receiver operating characteristic curve (AUC) with 95 % confidence intervals (CIs) in diagnosing dSMC were 74 % (66 % – 81 %; I2 = 84.6 %), 98 % (94 % – 99 %; I2 = 94.4 %), and 0.91 (0.88 – 0.93), respectively, for M-NBI. The pooled sensitivity, specificity and AUC (95 %CI) were 84 % (76 % – 89 %; I2 = 76.9 %), 97 % (94 % – 99 %; I2 = 90.2 %), and 0.97 (0.95 – 0.98), respectively, for M-CE. M-NBI had lower sensitivity (P < 0.01) than M-CE with similar specificity (P = 0.32). Subgroup analyses and meta-regression indicated that endoscopic diagnostic criteria, study type, endoscope type, risk of index test bias, and histopathological diagnostic criteria might be the sources of heterogeneity. Conclusions M-NBI and M-CE had comparable specificities in diagnosing dSMC, but the sensitivity of M-NBI was slightly lower than that of M-CE.

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7

Xiao, Hong, Yuhe Shang, and Di Wu. "DSMC Simulation and Experimental Validation of Shock Interaction in Hypersonic Low Density Flow." Scientific World Journal 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/732765.

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Direct simulation Monte Carlo (DSMC) of shock interaction in hypersonic low density flow is developed. Three collision molecular models, including hard sphere (HS), variable hard sphere (VHS), and variable soft sphere (VSS), are employed in the DSMC study. The simulations of double-cone and Edney’s type IV hypersonic shock interactions in low density flow are performed. Comparisons between DSMC and experimental data are conducted. Investigation of the double-cone hypersonic flow shows that three collision molecular models can predict the trend of pressure coefficient and the Stanton number. HS model shows the best agreement between DSMC simulation and experiment among three collision molecular models. Also, it shows that the agreement between DSMC and experiment is generally good for HS and VHS models in Edney’s type IV shock interaction. However, it fails in the VSS model. Both double-cone and Edney’s type IV shock interaction simulations show that the DSMC errors depend on the Knudsen number and the models employed for intermolecular interaction. With the increase in the Knudsen number, the DSMC error is decreased. The error is the smallest in HS compared with those in the VHS and VSS models. When the Knudsen number is in the level of 10−4, the DSMC errors, for pressure coefficient, the Stanton number, and the scale of interaction region, are controlled within 10%.

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8

Yan, T. H., B. Wu, B. He, W. H. Li, and R. B. Wang. "A Novel Fuzzy Sliding-Mode Control for Discrete-Time Uncertain System." Mathematical Problems in Engineering 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/1530760.

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This paper considers the sliding-mode control problem for discrete-time uncertain systems. It begins by presenting a discrete variable speed reaching law and a discrete-time sliding-mode controller (DSMC) designed using the proposed reaching law, followed by an analysis of their stability and dynamic performance. A sliding-mode controller with simple fuzzy logic is then proposed to further strengthen the dynamic performance of the proposed sliding-mode controller. Finally, the presented DSMC and the DSMC with fuzzy control for adjusting the parameters in this paper are compared with one of the previous proposed classic DSMC systems. The results of this simulation show that the DSMC presented here can suppress chatter and ensure good dynamic performances when fuzzy logic is used to tune the parameters.

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Burt, Jonathan M., and Iain D. Boyd. "Convergence Detection in Direct Simulation Monte Carlo Calculations for Steady State Flows." Communications in Computational Physics 10, no. 4 (October 2011): 807–22. http://dx.doi.org/10.4208/cicp.090210.311210a.

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AbstractA new criterion is presented to detect global convergence to steady state, and to identify local transient characteristics, during rarefied gas flow simulations performed using the direct simulation Monte Carlo (DSMC) method. Unlike deterministic computational fluid dynamics (CFD) schemes, DSMC is generally subject to large statistical scatter in instantaneous flow property evaluations, which prevents the use of residual tracking procedures as are often employed in CFD simulations. However, reliable prediction of the time to reach steady state is necessary for initialization of DSMC sampling operations. Techniques currently used in DSMC to identify steady state convergence are usually insensitive to weak transient behavior in small regions of relatively low density or recirculating flow. The proposed convergence criterion is developed with the goal of properly identifying such weak transient behavior, while adding negligible computational expense and allowing simple implementation in any existing DSMC code. Benefits of the proposed technique over existing convergence detection methods are demonstrated for representative nozzle/plume expansion flow, hypersonic blunt body flow and driven cavity flow problems.

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Di Staso, G., H. J. H. Clercx, S. Succi, and F. Toschi. "Lattice Boltzmann accelerated direct simulation Monte Carlo for dilute gas flow simulations." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, no. 2080 (November 13, 2016): 20160226. http://dx.doi.org/10.1098/rsta.2016.0226.

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Hybrid particle–continuum computational frameworks permit the simulation of gas flows by locally adjusting the resolution to the degree of non-equilibrium displayed by the flow in different regions of space and time. In this work, we present a new scheme that couples the direct simulation Monte Carlo (DSMC) with the lattice Boltzmann (LB) method in the limit of isothermal flows. The former handles strong non-equilibrium effects, as they typically occur in the vicinity of solid boundaries, whereas the latter is in charge of the bulk flow, where non-equilibrium can be dealt with perturbatively, i.e. according to Navier–Stokes hydrodynamics. The proposed concurrent multiscale method is applied to the dilute gas Couette flow, showing major computational gains when compared with the full DSMC scenarios. In addition, it is shown that the coupling with LB in the bulk flow can speed up the DSMC treatment of the Knudsen layer with respect to the full DSMC case. In other words, LB acts as a DSMC accelerator. This article is part of the themed issue ‘Multiscale modelling at the physics–chemistry–biology interface’.

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11

CHAO, LIU, SANG KYU KWAK, and SANTOSH ANSUMALI. "DIRECT SIMULATION MONTE CARLO FOR DENSE HARD SPHERES." International Journal of Modern Physics C 25, no. 01 (December 2, 2013): 1340023. http://dx.doi.org/10.1142/s0129183113400238.

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We propose a modified direct simulation Monte Carlo (DSMC) method, which extends the validity of DSMC from rarefied to dense system of hard spheres (HSs). To assess this adapted method, transport properties of hard-sphere (HS) systems have been predicted both at dense states as well as dilute, and we observed the excellent accuracy over existing DSMC-based algorithms including the Enskog theory. The present approach provides an intuitive and systematic way to accelerate molecular dynamics (MD) via mesoscale approach.

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12

Paul, Satyam, and Ruben Morales-Menendez. "Chatter Mitigation in Milling Process Using Discrete Time Sliding Mode Control with Type 2-Fuzzy Logic System." Applied Sciences 9, no. 20 (October 16, 2019): 4380. http://dx.doi.org/10.3390/app9204380.

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In order to achieve a high-quality machining process with superior productivity, it is very important to tackle the phenomenon of chatter in an effective manner. The problems like tool wear and improper surface finish affect the milling process and are caused by self-induced vibration termed as chatter. A strategy to control chatter vibration actively in the milling process is presented. The mathematical modeling of the process is carried out initially. In this paper, an innovative technique of discrete time sliding mode control (DSMC) is blended with the type-2 fuzzy logic system. The proposed active controller results in a significantly high mitigation of vibration. The DSMC is linked to the time-varying gain which is an innovative approach to mitigate chattering. The theorem is laid down which validates that the system states are bounded in the case of DSMC-type-2 fuzzy. Stability analysis is carried out using Lyapunov candidate. The nonlinearities linked with the cutting forces and damper friction are handled effectively by using the type-2 fuzzy logic system. The performance of the DSMC-type-2 fuzzy concept is compared with the discrete time PID (D-PID) and discrete time sliding mode control for validating the effectiveness of the controller. The better performance of DSMC-type-2 fuzzy over D-PID and DSMC-T1 fuzzy in the minimization of milling chatter are validated by a numerical analysis approach.

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13

Yan, Jun-Juh, and Teh-Lu Liao. "Discrete sliding mode control for hybrid synchronization of continuous Lorenz systems with matched/unmatched disturbances." Transactions of the Institute of Measurement and Control 40, no. 5 (January 24, 2017): 1417–24. http://dx.doi.org/10.1177/0142331216683773.

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This paper is concerned with the hybrid synchronization of master-slave Lorenz systems with uncertainties. A new systematic design procedure to synchronize continuous master-slave Lorenz chaotic systems is proposed by using a discrete sliding mode control (DSMC). In contrast to the previous works, the design of DSMC can be simplified and only a single controller is needed to realize chaos synchronization. The proposed DSMC ensures the occurrence of the sliding mode. When the controlled system is in the sliding manifold, the effect of disturbances including matched and unmatched cases are discussed. The proposed results conclude the synchronization error of controlled master-slave systems with matched disturbances can be fully derived to zero or robustly suppressed in an estimated bound even with unmatched disturbances, which is not addressed in the literature. The numerical simulation results demonstrate the success and effectiveness of the proposed DSMC developed in this paper.

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Ren, Xiang, Junya Yuan, Bijiao He, Mingxing Zhang, and Guobiao Cai. "Grid criteria for numerical simulation of hypersonic aerothermodynamics in transition regime." Journal of Fluid Mechanics 881 (October 24, 2019): 585–601. http://dx.doi.org/10.1017/jfm.2019.756.

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Grid is an important factor in numerical simulation of hypersonic aerothermodynamics. This paper introduces three criteria for determining grid size in the transition flow regime when using the computational fluid dynamics (CFD) method or the direct simulation Monte Carlo (DSMC) method. The numerical relationship between these three criteria sizes is deduced according to the one-dimensional fluid theory. Then, the relationship is verified using the CFD method to simulate the flow around a two-dimensional cylinder. At the same time, the dependence of simulation accuracy on grid size in the CFD and DSMC methods is studied and the mechanism is given. The result shows that the simulation accuracy of heat flux especially depends on the normal grid size next to surfaces, where the $Re_{\mathit{cell},w}$ criterion and the $\unicode[STIX]{x1D706}_{w}$ criterion based on local parameters are applicable and equivalent, while the $Re_{\mathit{cell},\infty }$ criterion based on the free-stream parameter is only applicable under the assumption of constant viscosity coefficient and constant temperature wall conditions. On the other hand, the trend of the heat flux changing with grid size obtained by CFD and DSMC is exactly the opposite. Therefore, the grid size must be strictly satisfied with the grid criteria when comparing CFD with DSMC and even the hybrid DSMC with Navier–Stokes method.

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Misawa, E. A. "Discrete-Time Sliding Mode Control: The Linear Case." Journal of Dynamic Systems, Measurement, and Control 119, no. 4 (December 1, 1997): 819–21. http://dx.doi.org/10.1115/1.2802396.

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This paper discusses the application of a class of discrete-time sliding mode controllers (DSMC) which was previously shown to be robustly stable. Further insight into design and performance of DSMC is obtained considering the case of linear plants. A simple numerical example is used to illustrate the properties of this technique.

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Liu, Bo, De Chun Ba, Li Hua Fan, and Li Nan Zhou. "The Numerical Simulation Research of Disk-Type Molecular Pump Based on DSMC Method." Applied Mechanics and Materials 423-426 (September 2013): 2054–58. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.2054.

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First, the basic principle of the DSMC method is introduced, which include simulating process, calculating of collision and key technique about simulation. Then a detailed process of simulation analysis to Disk-type Molecular Pumps extraction process based on DSMC method, is described, such as establishing geometric model, meshing, selection of collision model, boundary simulation, etc. At last, the ongoing work is pointed out .

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Liang, Tengfei, and Wenjing Ye. "An Efficient Hybrid DSMC/MD Algorithm for Accurate Modeling of Micro Gas Flows." Communications in Computational Physics 15, no. 1 (January 2014): 246–64. http://dx.doi.org/10.4208/cicp.141112.160513a.

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AbstractAiming at simulating micro gas flows with accurate boundary conditions, an efficient hybrid algorithm is developed by combining the molecular dynamics (MD) method with the direct simulation Monte Carlo (DSMC) method. The efficiency comes from the fact that the MD method is applied only within the gas-wall interaction layer, characterized by the cut-off distance of the gas-solid interaction potential, to resolve accurately the gas-wall interaction process, while the DSMC method is employed in the remaining portion of the flow field to efficiently simulate rarefied gas transport outside the gas-wall interaction layer. A unique feature about the present scheme is that the coupling between the two methods is realized by matching the molecular velocity distribution function at the DSMC/MD interface, hence there is no need for one-to-one mapping between a MD gas molecule and a DSMC simulation particle. Further improvement in efficiency is achieved by taking advantage of gas rarefaction inside the gas-wall interaction layer and by employing the “smart-wall model” proposed by Barisiket al.The developed hybrid algorithm is validated on two classical benchmarks namely 1-D Fourier thermal problem and Couette shear flow problem. Both the accuracy and efficiency of the hybrid algorithm are discussed. As an application, the hybrid algorithm is employed to simulate thermal transpiration coefficient in the free-molecule regime for a system with atomically smooth surface. Result is utilized to validate the coefficients calculated from the pure DSMC simulation with Maxwell and Cercignani-Lampis gas-wall interaction models.

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Yang, Fuxiang, Jie Li, Chuanfu Xu, Dali Li, Haozhong Qiu, and Ao Xu. "MPI Parallelization of Numerical Simulations for Pulsed Vacuum Arc Plasma Plumes Based on a Hybrid DSMC/PIC Algorithm." Aerospace 9, no. 10 (September 23, 2022): 538. http://dx.doi.org/10.3390/aerospace9100538.

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The transport characteristics of the unsteady flow field in rarefied plasma plumes is crucial for a pulsed vacuum arc in which the particle distribution varies from 1016 to 1022 m−3. The direct simulation Monte Carlo (DSMC) method and particle-in-cell (PIC) method are generally combined to study this kind of flow field. The DSMC method simulates the motion of neutral particles, while the PIC method simulates the motion of charged ions. A hybrid DSMC/PIC algorithm is investigated here to determine the unsteady axisymmetric flow characteristics of vacuum arc plasma plume expansion. Numerical simulations are found to be consistent with the experiments performed in the plasma mass and energy analyzer (EQP). The electric field is solved by Poisson’s equation, which is usually computationally expensive. The compressed sparse row (CSR) format is used to store the huge diluted matrix and PETSc library to solve Poisson’s equation through parallel calculations. Double weight factors and two timesteps under two grid sets are investigated using the hybrid DSMC/PIC algorithm. The fine PIC grid is nested in the coarse DSMC grid. Therefore, METIS is used to divide the much smaller coarse DSMC grid when dynamic load imbalances arise. Two parameters are employed to evaluate and distribute the computational load of each process. Due to the self-adaption of the dynamic-load-balancing parameters, millions of grids and more than 150 million particles are employed to predict the transport characteristics of the rarefied plasma plume. Atomic Ti and Ti2+ are injected into the small cylinders. The comparative analysis shows that the diffusion rate of Ti2+ is faster than that of atomic Ti under the electric field, especially in the z-direction. The fully diffuse reflection wall model is adopted, showing that neutral particles accumulate on the wall, while charged ions do not—due to their self-consistent electric field. The maximum acceleration ratio is about 17.94.

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USAMI, Masaru, and Hiroyuki FURUKAWA. "DSMC Calculation on Underexpanded Jets." AEROSPACE TECHNOLOGY JAPAN, THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 15 (2016): 117–25. http://dx.doi.org/10.2322/astj.15.117.

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Fang, X., and J. Tang. "A Direct Simulation Monte Carlo Approach for the Analysis of Granular Damping." Journal of Computational and Nonlinear Dynamics 2, no. 2 (November 13, 2006): 180–89. http://dx.doi.org/10.1115/1.2447502.

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Granular damping, which possesses promising features for vibration suppression in harsh environments such as in turbo-machinery and spacecraft, has been studied using empirical analysis and more recently using the discrete element method (DEM). The mechanism of granular damping is nonlinear and, when numerical analyses are employed, usually a relatively long simulation time of structural vibration is needed to reflect the damping behavior. The present research explores the granular damping analysis by means of the direct simulation Monte Carlo (DSMC) approach. Unlike the DEM that tracks the motion of granules based upon the direct numerical integration of Newton’s equations, the DSMC is a statistical method derived from the Boltzmann equation to describe the velocity evolution of the granular system. Since the exact time and locations of contacts among granules are not calculated in the DSMC, a significant reduction in computational time/cost can be achieved. While the DSMC has been exercised in a variety of gas/granular systems, its implementation to granular damping analysis poses unique challenges. In this research, we develop a new method that enables the coupled analysis of the stochastic granular motion and the structural vibration. The complicated energy transfer and dissipation due to the collisions between the granules and the host structure and among the granules is directly analyzed, which is essential to damping evaluation. Also, the effects of granular packing ratio and the excluded volume of granules, which may not be considered in the conventional DSMC approach, are explicitly incorporated in the analysis. A series of numerical studies are performed to highlight the accuracy and efficiency of the new approach.

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AHMADZADEGAN, AMIR, JOHN WEN, and METIN RENKSIZBULUT. "THE ROLE OF THE VELOCITY DISTRIBUTION IN THE DSMC PRESSURE BOUNDARY CONDITION FOR GAS MIXTURES." International Journal of Modern Physics C 23, no. 12 (December 2012): 1250087. http://dx.doi.org/10.1142/s0129183112500878.

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A prescribed pressure is the most common flow boundary condition used in flow simulations. In the Direct Simulation Monte Carlo (DSMC) method, boundary pressure is controlled by the number flux of the simulating molecules entering the domain. In the conventional DSMC algorithm, this number flux is calculated iteratively using sampled values of velocity and number density by means of an expression derived from the Maxwell distribution function. It is known that this procedure does not work well for low speed flows which are of interest in most micro-flow applications and the statistical scatter of the DSMC results is generally stated to be the main reason. However, the Maxwell distribution used in the pressure boundary treatment is valid for equilibrium conditions, and therefore, current implementations of the DSMC pressure boundary treatment are limited to boundaries with sufficiently small rarefaction effects. This is not the case for some practical problems in which highly rarefied flows through the boundaries lead to considerable nonequilibrium effects. In this study, an expression for the species number flux is derived using the Chapman–Enskog velocity distribution to improve the pressure boundary condition. The resulting algorithm is then used for modeling a micro-channel binary gas mixture flow with prescribed pressure boundary conditions.

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Huang, Juan-Chen, Kun Xu, and Pubing Yu. "A Unified Gas-Kinetic Scheme for Continuum and Rarefied Flows III: Microflow Simulations." Communications in Computational Physics 14, no. 5 (November 2013): 1147–73. http://dx.doi.org/10.4208/cicp.190912.080213a.

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AbstractDue to the rapid advances in micro-electro-mechanical systems (MEMS), the study of microflows becomes increasingly important. Currently, the molecular-based simulation techniques are the most reliable methods for rarefied flow computation, even though these methods face statistical scattering problem in the low speed limit. With discretized particle velocity space, a unified gas-kinetic scheme (UGKS) for entire Knudsen number flow has been constructed recently for flow computation. Contrary to the particle-based direct simulation Monte Carlo (DSMC) method, the unified scheme is a partial differential equation-based modeling method, where the statistical noise is totally removed. But, the common point between the DSMC and UGKS is that both methods are constructed through direct modeling in the discretized space. Due to the multiscale modeling in the unified method, i.e., the update of both macroscopic flow variables and microscopic gas distribution function, the conventional constraint of time step being less than the particle collision time in many direct Boltzmann solvers is released here. The numerical tests show that the unified scheme is more efficient than the particle-based methods in the low speed rarefied flow computation. The main purpose of the current study is to validate the accuracy of the unified scheme in the capturing of non-equilibrium flow phenomena. In the continuum and free molecular limits, the gas distribution function used in the unified scheme for the flux evaluation at a cell interface goes to the corresponding Navier-Stokes and free molecular solutions. In the transition regime, the DSMC solution will be used for the validation of UGKS results. This study shows that the unified scheme is indeed a reliable and accurate flow solver for low speed non-equilibrium flows. It not only recovers the DSMC results whenever available, but also provides high resolution results in cases where the DSMC can hardly afford the computational cost. In thermal creep flow simulation, surprising solution, such as the gas flowing from hot to cold regions along the wall surface, is observed for the first time by the unified scheme, which is confirmed later through intensive DSMC computation.

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Schrock, Christopher R., and Aihua W. Wood. "Convergence of A Distributional Monte Carlo Method for the Boltzmann Equation." Advances in Applied Mathematics and Mechanics 4, no. 1 (February 2012): 102–21. http://dx.doi.org/10.4208/aamm.10-m11113.

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AbstractDirect Simulation Monte Carlo (DSMC) methods for the Boltzmann equation employ a point measure approximation to the distribution function, as simulated particles may possess only a single velocity. This representation limits the method to converge only weakly to the solution of the Boltzmann equation. Utilizing kernel density estimation we have developed a stochastic Boltzmann solver which possesses strong convergence for bounded and L∞ solutions of the Boltzmann equation. This is facilitated by distributing the velocity of each simulated particle instead of using the point measure approximation inherent to DSMC. We propose that the development of a distributional method which incorporates distributed velocities in collision selection and modeling should improve convergence and potentially result in a substantial reduction of the variance in comparison to DSMC methods. Toward this end, we also report initial findings of modeling collisions distributionally using the Bhatnagar-Gross-Krook collision operator.

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Kurihara, J., K. I. Oyama, N. Iwagami, and T. Takahashi. "Numerical simulation of 3-D flow around sounding rocket in the lower thermosphere." Annales Geophysicae 24, no. 1 (March 7, 2006): 89–95. http://dx.doi.org/10.5194/angeo-24-89-2006.

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Abstract. Numerical simulations using the Direct Simulation Monte Carlo (DSMC) method are known to be useful for analyses of aerodynamic effects on in-situ rocket measurements in the lower thermosphere, but the DSMC analysis of a spin modulation caused by an asymmetric flow around the rocket spin axis has been restricted to the two-dimensional and axially symmetric simulations in actual sounding rocket experiments. This study provides a quantitative analysis of the spin modulation using a three-dimensional (3-D) simulation of the asymmetric flow with the DSMC method. Clear spin modulations in the lower thermospheric N2 density measurement by a rocket-borne instrument are simulated using the rocket attitude and velocity, the simplified payload structure, and the approximated atmospheric conditions. Comparison between the observed and simulated spin modulations show a very good agreement within 5% at around 100km. The results of the simulation are used to correct the spin modulations and derive the absolute densities in the background atmosphere.

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Zribi, Mohamed, Muthana T. Alrifai, and Nejib Smaoui. "Control of Chaos in a Single Machine Infinite Bus Power System Using the Discrete Sliding Mode Control Technique." Discrete Dynamics in Nature and Society 2018 (June 6, 2018): 1–14. http://dx.doi.org/10.1155/2018/5758324.

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Under certain conditions, power systems may exhibit chaotic behaviors which are harmful and undesirable. In this paper, the discrete time sliding mode control technique is used to control a chaotic power system. The objective of the control is to eliminate the chaotic oscillations and to bring order to the power system. Two discrete time sliding mode control (DSMC) schemes are proposed for a fourth order discrete time chaotic power system. The first DSMC control scheme is based on the well-known exponential reaching law. The second DSMC control scheme is based on the recently developed double power reaching law. It is shown that the states of the controlled system converge to their desired values. Simulation results are presented for different values of the gains of the controllers as well as for different initial conditions. These results indicate that both control schemes work well. However, the simulation results show that the second control scheme gave better results since it was able to greatly reduce the chattering problem.

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Boyd, I. D. "Temperature dependence of rotational relaxation in shock waves of nitrogen." Journal of Fluid Mechanics 246 (January 1993): 343–60. http://dx.doi.org/10.1017/s0022112093000163.

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Computations are presented for one-dimensional Shockwaves of diatomic nitrogen. The direct simulation Monte Carlo method (DSMC) is employed. A model which allows the use of the Sutherland viscosity model in the DSMC technique is further developed to include the modelling of rotational relaxation. This is achieved by employing a temperature-dependent expression for the rotational collision number to simulate the rate of relaxation, in contrast to earlier DSMC studies which employed a constant value for the collision number. The behaviour of the new model is first considered for rotational relaxation in a heat bath. Comparison is made with the more traditional DSMC collision model termed the variable hard sphere (VHS) model in which the viscosity has a fixed temperature exponent. These two models are then applied to a number of shock-wave cases for which experimental data exist. These have Mach numbers ranging from 1.5 to 26, yet the enthalpies involved are sufficiently low to allow omission of vibrational relaxation. It is found that both the VHS and Sutherland viscosity models give excellent agreement with the experimental data for shock-wave thickness, and for profiles of density, rotational temperature, and velocity. The most significant finding of the study is that the reciprocal shock thickness varies with the upstream temperature condition. This variation is observed in the experimental data, and is simulated numerically by employing the temperature-dependent expression for the rotational collision number.

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Karthikeyan, Viji, Anil Kumar Tiwari, and Chitra Kandasamy. "Real time hardware implementation of discrete sliding mode fuzzy controlled buck converter using digital signal processor." International Journal of Electrical and Computer Engineering (IJECE) 12, no. 5 (October 1, 2022): 4801. http://dx.doi.org/10.11591/ijece.v12i5.pp4801-4807.

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This paper deals with the real time hardware implementation of discrete sliding mode fuzzy control (DSMFC) for buck converter using digital signal processor (DSP). Applications like electric vehicle suspension control, flight dynamic control, robot position control and engine throttle position control; sliding mode control (SMC) plays a major role. Hardware realization is difficult with SMC strategy due to the continuous gain change results in chattering problem and actuator or contact may break. To resolve this problem the fuzzy logic (FL) approach has combined with the robust technique discrete sliding mode control (DSMC) to develop a new strategy for DSMFC. The mathematical modeling of the controller is done using MATLAB/Simulink software and practical design of the converter is also realized. The robustness of the controller is proved by introducing sudden change in input voltage as well as load with the help of switching circuit in hardware realization. The obtained practical results are verified by comparing with the simulation output and reference value.

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Jeon, Woojin, Seungwook Baek, Jaehyun Park, and Dongsung Ha. "Rocket Plume Analysis with DSMC Method." Journal of the Korean Society of Propulsion Engineers 18, no. 5 (October 1, 2014): 54–61. http://dx.doi.org/10.6108/kspe.2014.18.5.054.

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29

Furukawa, Yusuke, Yasuhiro Kawano, and Masaru Usami. "0119 DSMC Calculation of Vortex Shedding." Proceedings of the Fluids engineering conference 2009 (2009): 41–42. http://dx.doi.org/10.1299/jsmefed.2009.41.

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30

Lian, Yu-Yung, Yen-Sen Chen, K. C. Tseng, J. S. Wu, Bill Wu, and Luke Yang. "Improved parallelized hybrid DSMC–NS method." Computers & Fluids 45, no. 1 (June 2011): 254–60. http://dx.doi.org/10.1016/j.compfluid.2010.12.015.

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31

Masao, Yusuke, Masaya Okano, and Mitsuhiro Matsumoto. "DSMC scheme to study phonon dynamics." Journal of Mechanical Science and Technology 25, no. 1 (January 2011): 21–26. http://dx.doi.org/10.1007/s12206-010-1111-z.

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32

Mozaffari, Mohammad Sajjad, and Ehsan Roohi. "On the thermally-driven gas flow through divergent micro/nanochannels." International Journal of Modern Physics C 28, no. 12 (December 2017): 1750143. http://dx.doi.org/10.1142/s0129183117501431.

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A detailed study on thermally driven flows through divergent micro/nanochannels is presented. Rarefied gas flow behavior and thermal mass flow rate were investigated with different divergence angles ranging between 0[Formula: see text] and 7[Formula: see text] at two aspect ratios ([Formula: see text]) using particle-based direct simulation Monte-Carlo (DSMC) method. We compare our DSMC solutions for normalized thermal mass flow rate with the numerical solution of the Boltzmann–Krook–Walender (BKW) model and Bhatnagar–Gross–Krook (BGK) model and asymptotic theory over a wide range of Knudsen number in the transition regime. The flow field properties including Mach number, pressure, overall temperature and magnitude of shear stress are examined in detail. Based on our analysis, we observed an approximately constant velocity and pressure distribution at a microchannel with a small opening angle. Our results also demonstrate that the heat lines from weakly nonlinear form of Sone constitutive law and DSMC show good agreement at low Knudsen numbers. Moreover, we show that the effect of divergence angle is influential in increasing normalized thermal mass flow rate at early transition regime.

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33

Karami-Mollaee, Ali, Hamed Tirandaz, and Oscar Barambones. "Dynamic sliding mode position control of induction motors based load torque compensation using adaptive state observer." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 37, no. 6 (November 5, 2018): 2249–62. http://dx.doi.org/10.1108/compel-12-2017-0525.

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Purpose The purpose of this paper is position control scheme for a servo induction motor (SIM) with uncertainty has been designed using a new observer issue and a dynamic sliding mode control (DSMC). Design/methodology/approach In DSMC, the chattering is removed due to the integrator (or a low-pass filter) which is placed before the input control of the plant. However, in DSMC, the augmented system has one dimension bigger than the actual system (if integrator is used) and then, the plant model should be completely known. To solve this problem in SIM, the use of a new adaptive state observer (ASO) is proposed. Findings The advantage of the proposed approach is to maintain the system controlled under the external load torque variations. Then, the load variations do not affect the motor positioning. Moreover, it is demonstrated that the observer error converges to zero based on the Lyapunov stability theory. Originality/value The knowledge of the upper bound for the system uncertainty is not necessary in an adaptive state observer, which is important in practical implementation. Simulation results are presented to demonstrate the performance of the proposed approach.

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34

Guo, Li Dong, Li Xin Yang, and He Ming Jia. "Dynamic Sliding-Mode Control with Backstepping for Underactuated AUV in Diving Plane." Applied Mechanics and Materials 220-223 (November 2012): 1148–52. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.1148.

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A dynamic sliding-mode control (DSMC) with backstepping is proposed for diving control of autonomous underwater vehicle (AUV), where surge force and stern plane are only available for vehicle's 3DOF diving motion. First, an equivalent model of AUV is developed. Then, the DSMC with an asymptotical sliding surface is proposed for the trajectory tracking control of AUV. Moreover, the analysis of stability can be completed by Lyapunov stability theory. Finally, To demonstrate the effectiveness of the proposed method, the simulation results are illustrated in this paper. simulation results show that, the tracking precision and the robustness of the system are improved under the proposed control method.

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35

Anile, Marcello A., Jose A. Carrillo, Irene M. Gamba, and Chi-Wang Shu. "Approximation of the BTE by a Relaxation-time Operator: Simulations for a 50 nm-channel Si Diode." VLSI Design 13, no. 1-4 (January 1, 2001): 349–54. http://dx.doi.org/10.1155/2001/35094.

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In this work we present comparisons between DSMC simulations of the full BTE and deterministic simulations of a relaxation-time approximation for a nowadays size Si diode. We assume a field dependent relaxation time fitted to give the same drift speed (mean velocity) as DSMC simulations for bulk Si. We compute the density, mean velocity, force field, potential drop, energy and I-V curves of both models and plot the pdf of the deterministic relaxation-time model. We also compare the results to augmented drift-diffusion models proposed in the literature to approximate the relaxation time system in the quasi-ballistic regime. The quasi-ballistic and ballistic regimes are distinguished by using local dimensionless parameters.

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36

Latosiński, Paweł, and Andrzej Bartoszewicz. "Zero-Width Quasi-Sliding Mode Band in the Presence of Non-Matched Uncertainties." Energies 14, no. 11 (May 22, 2021): 3011. http://dx.doi.org/10.3390/en14113011.

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Sliding mode control strategies are well known for ensuring robustness of the system with respect to disturbance and model uncertainties. For continuous-time plants, they achieve this property by confining the system state to a particular hyperplane in the state space. Contrary to this, discrete-time sliding mode control (DSMC) strategies only drive the system representative point to a certain vicinity of that hyperplane. In established literature on DSMC, the width of this vicinity has always been strictly greater than zero in the presence of uncertainties. Thus, ideal sliding motion was considered impossible for discrete-time systems. In this paper, a new approach to DSMC design is presented with the aim of driving the system representative point exactly onto the sliding hyperplane even in the presence of uncertainties. As a result, the quasi-sliding mode band width is effectively reduced to zero and ideal discrete-time sliding motion is ensured. This is achieved with the proper selection of the sliding hyperplane, using the unique properties of relative degree two sliding variables. It is further demonstrated that, even in cases where selection of a relative degree two sliding variable is impossible, one can use the proposed technique to significantly reduce the quasi-sliding mode band width.

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37

Beckmann, Alexander, Anirudh Rana, Manuel Torrilhon, and Henning Struchtrup. "Evaporation Boundary Conditions for the Linear R13 Equations Based on the Onsager Theory." Entropy 20, no. 9 (September 6, 2018): 680. http://dx.doi.org/10.3390/e20090680.

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Due to the failure of the continuum hypothesis for higher Knudsen numbers, rarefied gases and microflows of gases are particularly difficult to model. Macroscopic transport equations compete with particle methods, such as the Direct Simulation Monte Carlo method (DSMC), to find accurate solutions in the rarefied gas regime. Due to growing interest in micro flow applications, such as micro fuel cells, it is important to model and understand evaporation in this flow regime. Here, evaporation boundary conditions for the R13 equations, which are macroscopic transport equations with applicability in the rarefied gas regime, are derived. The new equations utilize Onsager relations, linear relations between thermodynamic fluxes and forces, with constant coefficients, that need to be determined. For this, the boundary conditions are fitted to DSMC data and compared to other R13 boundary conditions from kinetic theory and Navier–Stokes–Fourier (NSF) solutions for two one-dimensional steady-state problems. Overall, the suggested fittings of the new phenomenological boundary conditions show better agreement with DSMC than the alternative kinetic theory evaporation boundary conditions for R13. Furthermore, the new evaporation boundary conditions for R13 are implemented in a code for the numerical solution of complex, two-dimensional geometries and compared to NSF solutions. Different flow patterns between R13 and NSF for higher Knudsen numbers are observed.

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38

SUGIYAMA, Ken-ichiro, Hideji YOSHIDA, and Ryoji ISHIGURO. "Simulation of Potassium Condensation by DSMC Method." Journal of the Atomic Energy Society of Japan / Atomic Energy Society of Japan 36, no. 10 (1994): 976–80. http://dx.doi.org/10.3327/jaesj.36.976.

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39

Wadsworth, Dean C., and Ingrid J. Wysong. "Vibrational favoring effect in DSMC dissociation models." Physics of Fluids 9, no. 12 (December 1997): 3873–84. http://dx.doi.org/10.1063/1.869487.

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40

Gimelshein, Sergey, and Ingrid Wysong. "DSMC modeling of flows with recombination reactions." Physics of Fluids 29, no. 6 (June 2017): 067106. http://dx.doi.org/10.1063/1.4986529.

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41

USAMI, Masaru, and Tetsuo OGAWA. "Automatic Programming System of the DSMC Method." Proceedings of the JSME annual meeting 2003.6 (2003): 187–88. http://dx.doi.org/10.1299/jsmemecjo.2003.6.0_187.

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42

Wu, J. S., K. C. Tseng, and T. J. Yang. "Parallel Implementation of DSMC Using Unstructured Mesh." International Journal of Computational Fluid Dynamics 17, no. 5 (October 2003): 405–22. http://dx.doi.org/10.1080/1061856031000081497.

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43

Huang, Fei, Xuhong Jin, Wenlong Mei, and Xiaoli Cheng. "A New Parallel Algorithm of DSMC Method." Procedia Engineering 126 (2015): 622–27. http://dx.doi.org/10.1016/j.proeng.2015.11.250.

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44

Bird, G. A. "Recent advances and current challenges for DSMC." Computers & Mathematics with Applications 35, no. 1-2 (January 1998): 1–14. http://dx.doi.org/10.1016/s0898-1221(97)00254-x.

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45

Liou, W. W., and Y. Fang. "Heat transfer in microchannel devices using DSMC." Journal of Microelectromechanical Systems 10, no. 2 (June 2001): 274–79. http://dx.doi.org/10.1109/84.925780.

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46

Matsuda, Takuya, Hiromi Mizutani, and Henri M. J. Boffin. "Application of DSMC method to astrophysical flows." Symposium - International Astronomical Union 208 (2003): 425–26. http://dx.doi.org/10.1017/s0074180900207584.

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The Direct Simulation Monte Carlo (DSMC) method, developed originally to calculate rarefied gas dynamical problems, is applied to continuous flow including shocks assuming that the Knudsen number is sufficiently small. In particular, we study the formation of spiral shocks in the accretion disc of a close binary system. The method involves viscosity and thermal conduction automatically, and can thus simulate turbulent viscosity.

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47

Mohammadzadeh, Alireza, and Henning Struchtrup. "Velocity dependent Maxwell boundary conditions in DSMC." International Journal of Heat and Mass Transfer 87 (August 2015): 151–60. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2015.03.045.

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48

Gallis, M. A., J. R. Torczynski, D. J. Rader, and G. A. Bird. "Convergence behavior of a new DSMC algorithm." Journal of Computational Physics 228, no. 12 (July 2009): 4532–48. http://dx.doi.org/10.1016/j.jcp.2009.03.021.

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49

Berg, J. J., D. B. Goldstein, P. L. Varghese, and L. M. Trafton. "DSMC simulation of Europa water vapor plumes." Icarus 277 (October 2016): 370–80. http://dx.doi.org/10.1016/j.icarus.2016.05.030.

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Wu, J. S., and K. C. Tseng. "Parallel DSMC method using dynamic domain decomposition." International Journal for Numerical Methods in Engineering 63, no. 1 (2005): 37–76. http://dx.doi.org/10.1002/nme.1232.

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