• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.144-153
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• 2009

To study the plume effects in the rarefied region, the Direct Simulation Monte Carlo(DSMC) method is usually adopted because the plume field usually contains the entire range of flow regime from the near-continuum in the vicinity of nozzle exit through transitional state to free molecular at far field region from the nozzle. The objective of this study is to investigate the behaviors of a small monopropellant thruster plume in the rarefied region numerically using DSMC method. To deduce accurate results efficiently, the preconditioned scheme is introduced to calculate continuum flow fields inside thruster to predict nozzle exit properties used for inlet conditions of DSMC method. By combining these two methods, the rarefied flow characteristics of plume such as strong nonequilibrium near nozzle exit, large back flow region, etc, can be investigated.

• 한국전산유체공학회:학술대회논문집
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• 1995.10a
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• pp.241-245
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• 1995

This paper presents the studies on the variation of shape and thickness of a normal shock wave with Mach number and density by using the most useful numerical technique in rarefied gas regime, DSMC(Direct Simulation Monte Carlo). Calculations are peformed for the three different Mach numbers and for one Mach number with different densities. From the obtained results, we find that the shock thickness is decreasing with increasing Mach number, and there are much variations in thickness and shape with decreasing density. Also, there is a noticeable overshoot of the translational temperature near the shock center in the case of a large Mach number.

• International Journal of Aeronautical and Space Sciences
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• v.14 no.3
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• pp.215-221
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• 2013

The basic quantitative tool for the study of hypersonic rarefied flows is the direct simulation Monte Carlo method (DSMC). The DSMC method requires a large amount of computer memory and performance and is unreasonably expensive at the first stage of spacecraft design and trajectory analysis. A possible solution to this problem is approximate engineering methods. However, the Monte Carlo method remains the most reliable approach to compare to the engineering methods that provide good results for the global aerodynamic coefficients of various geometry designs. This paper presents the calculation results of aerodynamic characteristics for spacecraft vehicles in the free molecular, the transitional and the continuum regimes using the local engineering method. Results and methods would be useful to calculate aerodynamics for new-generation hypersonic vehicle designs.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.769-771
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• 2011

The satellite payloaded on the 2nd stage of KSLV-I is planned to perform CCAM(Contamination and Collision Avoidance Maneuver) not to collide with KM(Kick Motor). At the moment, the satellite should pass through low density environment not to be contaminated by KM plume due to residual thrust. Therefore, it is necessary to predict the flow field of KM plume by residual thrust. In this paper, DSMC (Direct Simulation Monte-Carlo) method, which is widely accepted to simulate in rarefied regime, is used to compute the density field of KM plume by residual thrust and the result of DSMC simulation was compared with that of FLUENT to validate it.