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.

Development of Object-Oriented Direct Simulation Monte Carlo Code for Modeling of Rarefied Flow around Geometries of Arbitrary Shapes

2011 ◽  
Vol 110-116 ◽  
pp. 2491-2496
Author(s):  
Sourabh Jain ◽  
Prabhu Ramachandran
Keyword(s):  
Monte Carlo ◽  
Heat Conduction Problem ◽  
Direct Simulation Monte Carlo ◽  
Object Oriented ◽  
Navier Stokes ◽  
Monte Carlo Code ◽  
Direct Simulation ◽  
Rarefied Flow ◽  
Simulation Monte Carlo ◽  
Arbitrary Shapes

Rarefied flows cannot be accurately simulated using Navier-Stokes (N-S) equations. The Direct Simulation Monte-Carlo (DSMC) technique is a particle based method for accurate simulation of flows under such conditions. A DSMC code is developed using an object-oriented (OO) approach which can simulate flows around arbitrary shapes. Hence, the flux from such boundaries can be correctly predicted. The object-oriented approach enables for easy modification of the code. For example, it is easy to use different collision models to implement different relaxation algorithm. The code is validated for the one-dimensional Fourier heat conduction problem. Results for the development of a shock due to supersonic flow over a 15 degree wedge are also presented. Inclined boundary of the wedge is correctly captured as the particles interact with the the exact shape of the boundary. Shock angle is found more than expected due to rarefaction effects.

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.

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