Development of a General Parallel Three-Dimensional Direct Simulation Monte Carlo Code

2005 ◽  
Author(s):  
J.-S. Wu
Keyword(s):  
Monte Carlo ◽  
Three Dimensional ◽  
Direct Simulation Monte Carlo ◽  
Monte Carlo Code ◽  
Direct Simulation ◽  
Simulation Monte Carlo

Scale Effects on Rarefied Supersonic Flows in Nanochannels

2008 ◽  
Author(s):  
Nikolaos A. Gatsonis ◽  
Wael G. Al Kouz ◽  
Ryan E. Chamberlin
Keyword(s):  
Monte Carlo ◽  
Supersonic Flow ◽  
Knudsen Number ◽  
Scale Effects ◽  
Three Dimensional ◽  
Direct Simulation Monte Carlo ◽  
Supersonic Flows ◽  
Direct Simulation ◽  
Aspect Ratios ◽  
Simulation Monte Carlo

The supersonic flow of nitrogen into a nanochannel is investigated using a three dimensional unstructured Direct Simulation Monte Carlo (U3DSMC) method. The U3DSMC code is validated by comparisons with previous 2D DSMC simulations of flows in micron-scale channels. Rectangular nanochannels with heights between 100 nm to 1000 nm, and aspect ratios L/H of 1, 10, 100 are used in the U3DSMC investigation. The Mach 5.9 freestream has a pressure of 0. 1atm and Knudsen numbers of 0.481, 0.962 and 4.81. The nanochannel walls are assumed to be diffusively reflecting at the freestream temperature. The simulations show the development of a disturbance region upstream from the inlet that depends on the Knudsen number. For the L/H = 10 and L/H = 100 nanochannels considered the velocity decreases from its freestream value velocity decreases from its freestream value and becomes subsonic inside the nanochannel. The temperature shows an enhancement region near the inlet while the density shows an enhancement region inside the nanochannel.

Direct Simulation Monte Carlo Calculations of Three Dimensional Non-Continuum Gas Flows

2002 ◽  
Author(s):  
Fang Yan ◽  
Bakhtier Farouk ◽  
Jeremy Johnson
Keyword(s):  
Monte Carlo ◽  
Couette Flow ◽  
Three Dimensional ◽  
Direct Simulation Monte Carlo ◽  
Particle Removal ◽  
Direct Simulation ◽  
Transition Flow ◽  
Multiprocessor Computer ◽  
Wide Range ◽  
Simulation Monte Carlo

This paper describes the parallel implementation of a three-dimensional direct simulation Monte Carlo (DSMC) code using the OpenMP procedure on a shared memory multiprocessor computer. A dynamic domain decomposition is performed to maintain load balance among the threads. Performance tests are conducted to evaluate the effect of granularity on efficiency. It is shown that the parallel performance is dependent on the problem size. For larger-scale problems, better efficiency can be expected. Synchronization overhead due to data contention is reduced by re-arranging particle removal procedure. The parallel code is used to simulate flow through a rectangular channel with a high-speed moving wall (Couette flow). For high Knudsen (Kn) numbers, the Couette flow characteristics are found to be very different from their continuum counterparts. ‘Ultimate pressures’ are calculated for a wide range of Kn number flows. The variation of the ultimate pressure with Kn number is computed for given wall speed. Maximum compression ratio is obtained in the transition flow region.

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.

Modelling Rarefied Hypersonic Reactive Flows Using the Direct Simulation Monte Carlo Method

2015 ◽  
Vol 18 (4) ◽  
pp. 1095-1121 ◽  
Author(s):  
Ming-Chung Lo ◽  
Cheng-Chin Su ◽  
Jong-Shinn Wu ◽  
Kun-Chang Tseng
Keyword(s):  
Monte Carlo ◽  
Hypersonic Flow ◽  
Direct Simulation Monte Carlo ◽  
Test Cases ◽  
Monte Carlo Code ◽  
Direct Simulation ◽  
Reactive Flows ◽  
Flow Past ◽  
Flow Past A Cylinder ◽  
Simulation Monte Carlo

AbstractThis paper presents the implementation, validation and application of TCE (total collision energy) model for simulating hypersonic reactive flows in a parallel direct simulation Monte Carlo code, named PDSC++, using an unstructured grid. A series of benchmarking test cases, which include reproduction of theoretical rate constants in a single cell, 2D hypersonic flow past a cylinder and 2D-axisymmetric hypersonic flow past a sphere, were performed to validate the implementation. Finally, detailed aerothermodynamics of the flown reentry Apollo 6 Command Module at 105 km is simulated to demonstrate the powerful capability of the PDSC++in treating realistic hypersonic reactive flow at high altitude.

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