Unified Gas Kinetic Scheme and Direct Simulation Monte Carlo Computations of High-Speed Lid-Driven Microcavity Flows

2015 ◽  
Vol 17 (5) ◽  
pp. 1127-1150 ◽  
Author(s):  
Vishnu Venugopal ◽  
Sharath S. Girimaji
Keyword(s):  
Monte Carlo ◽  
High Speed ◽  
Direct Simulation Monte Carlo ◽  
Kinetic Scheme ◽  
Cavity Flow ◽  
Direct Simulation ◽  
Driven Cavity ◽  
Rarefied Flows ◽  
Simulation Monte Carlo ◽  
Unified Gas Kinetic Scheme

AbstractAccurate simulations of high-speed rarefied flows present many physical and computational challenges. Toward this end, the present work extends the Unified Gas Kinetic Scheme (UGKS) to a wider range of Mach and Knudsen numbers by implementing WENO (Weighted Essentially Non-Oscillatory) interpolation. Then the UGKS is employed to simulate the canonical problem of lid-driven cavity flow at high speeds. Direct Simulation Monte Carlo (DSMC) computations are also performed when appropriate for comparison. The effect of aspect ratio, Knudsen number and Mach number on cavity flow physics is examined leading to important insight.

Modelling of chemical reactions in hypersonic rarefied flow with the direct simulation Monte Carlo method

1996 ◽  
Vol 312 ◽  
pp. 149-172 ◽  
Author(s):  
Michael A. Gallis ◽  
John K. Harvey
Keyword(s):  
Monte Carlo ◽  
Chemical Reactions ◽  
Energy Exchange ◽  
Chemical Reactivity ◽  
Direct Simulation Monte Carlo ◽  
Direct Simulation ◽  
Rarefied Flow ◽  
Rarefied Flows ◽  
Exchange Processes ◽  
Simulation Monte Carlo

In this paper the phenomenon of chemical reactivity in hypersonic rarefied flows is examined. A new model is developed to describe the reactions and post-collision energy exchange processes that take place under conditions of molecular non-equilibrium. The new scheme, which is applied within the framework of the direct simulation Monte Carlo (DSMC) method, draws its inspiration from the principles of maximum entropy which were developed by Levine & Bernstein. Sample hypersonic flow fields, typical of spacecraft re-entry conditions in which reactions play an important role, are presented and compared with results from experiments and other DSMC calculations. The latter use traditional methods for the modelling of chemical reactions and energy exchange. The differences are discussed and evaluated.

Non-equilibrium thermal transport and entropy analyses in rarefied cavity flows

2019 ◽  
Vol 864 ◽  
pp. 995-1025 ◽  
Author(s):  
Vishnu Venugopal ◽  
Divya Sri Praturi ◽  
Sharath S. Girimaji
Keyword(s):  
Thermal Transport ◽  
Direct Simulation Monte Carlo ◽  
Kinetic Scheme ◽  
Driven Cavity ◽  
Rarefied Flows ◽  
Flow Simulations ◽  
Extended Thermodynamic ◽  
Simulation Monte Carlo ◽  
Mach Numbers ◽  
Non Equilibrium

Thermal transport in rarefied flows far removed from thermodynamic equilibrium is investigated using kinetic-theory-based numerical simulations. Two numerical schemes – unified gas kinetic scheme (UGKS) and direct simulation Monte Carlo (DSMC) – are employed to simulate transport at different degrees of rarefaction. Lid-driven cavity flow simulations of argon gas are performed over a range of Knudsen numbers, Mach numbers and cavity shapes. Thermal transport is then characterized as a function of lid Mach number and Knudsen number for different cavity shapes. Vast deviations from the Fourier law – including thermal transport aligned along the direction of temperature gradient – are observed. Entropy implications are examined using Sackur–Tetrode and Boltzmann $H$-theorem formulations. At low Knudsen and Mach numbers, thermal transport is shown to be amenable to both entropy formulations. However, beyond moderate Knudsen and Mach numbers, thermal transport complies only with the Boltzmann $H$-theorem entropy statement. Two extended thermodynamic models are compared against simulation data and found to account for some of the observed non-equilibrium behaviour.

scholarly journals Simulation of flow in single and double-sided lid driven square cavities by direct simulation Monte Carlo method

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 3031-3045 ◽  
Author(s):  
Deepak Nabapure ◽  
Ram Kalluri
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Wall Motion ◽  
Direct Simulation Monte Carlo ◽  
Current Method ◽  
Cavity Flow ◽  
Direct Simulation ◽  
Complex Flow ◽  
Parallel Wall ◽  
Simulation Monte Carlo

The gaseous flow of monoatomic Argon in a double-sided lid-driven square cavity is investigated using the direct simulation Monte Carlo method for different degrees of rarefaction. The effect of the direction of wall motion and the magnitude of wall velocities on the flow physics are analyzed. Unlike the single-sided cavity flow, the double-sided cavity flow generates different vortex formations especially for the parallel wall motion of the wall. The problem, therefore, merits a thorough study, which is attempted in the present paper using the direct simulation Monte Carlo method. Certain complex flow phenomena which are not captured using the numerical methods for continuum flows are revealed by the current method employed in the study. Two counter-rotating vortices are observed for the parallel wall motion whereas only one primary vortex can be observed for the antiparallel case. The variation in the flow and thermal properties is found to be significant at the onset of the transition regime and much smaller in the free molecular regime.

scholarly journals Kinetic comparative study on Aerodynamic Characteristics of Hypersonic Reentry Vehicle from Near-continuous Flow to Free Molecular Flow

2021 ◽  
Author(s):  
Jin Li ◽  
Dingwu Jiang ◽  
Xiangren Geng ◽  
Jianqiang Chen
Keyword(s):  
Direct Simulation Monte Carlo ◽  
Kinetic Scheme ◽  
Aerodynamic Characteristics ◽  
Molecular Flow ◽  
Direct Simulation ◽  
Scaled Model ◽  
Reentry Vehicle ◽  
Simulation Monte Carlo ◽  
Unified Gas Kinetic Scheme ◽  
Inflow Conditions

Abstract A scaled model of the X38-like configuration was simulated under hypersonic conditions by the direct simulation Monte Carlo method and the unified gas kinetic scheme. The inflow conditions considered several different flow regimes, from the near-continuum though the slip-transitional to the free molecule regime. Flow fields and surface properties were compared in details between two methods. Not only the density and temperature contours distribution but also the surface pressure, heat flux, friction distribution, both kinetic methods give fairly consistent results. Aerodynamics of the model under hypersonic rarefied conditions were also obtained and compared. The results given by both methods agreed with each other very well. The effects of the Knudsen number and angle of attack were assessed. At the absence of experimental results, it is meaningful to carry out comparative studies and accelerate both methods to further progress.

scholarly journals Kinetic Comparative Study on Aerodynamic Characteristics of Hypersonic Reentry Vehicle from Near-Continuous Flow to Free Molecular Flow

2020 ◽  
Author(s):  
Jin Li ◽  
Dingwu Jiang ◽  
Xiangren Geng ◽  
Jianqiang Chen
Keyword(s):  
Continuous Flow ◽  
Direct Simulation Monte Carlo ◽  
Kinetic Scheme ◽  
Free Molecule ◽  
Direct Simulation ◽  
Scaled Model ◽  
Reentry Vehicle ◽  
Simulation Monte Carlo ◽  
Unified Gas Kinetic Scheme ◽  
Inflow Conditions

Abstract A scaled model of the X38-like configuration was simulated under hypersonic conditions by the direct simulation Monte Carlo method and the unified gas kinetic scheme. The inflow conditions considered several different flow regimes, from the near-continuum though the slip-transitional to the free molecule regime. Flow fields and surface properties were compared in details between two methods. Not only the density and temperature contours distribution but also the surface pressure, heat flux, friction distribution, both kinetic methods give fairly consistent results. Aerodynamics of the model under hypersonic rarefied conditions were also obtained and compared. The results given by both methods agreed with each other very well. The effects of the Knudsen number and angle of attack were assessed. At the absence of experimental results, it is meaningful to carry out comparative studies and accelerate both methods to further progress.

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