• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.4
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• pp.33-38
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• 2003

The Physics of the Plume-induced shock and separation Particularly at a high Plume to exit pressure ratio and supersonic speeds up to Mach 3.0 with and without a passive control method, porous extension, were studied using computational techniques. Mass-averaged Navier-Stokes equations with the RNG $\kappa$-$\varepsilon$ turbulence model were solved using a fully implicit finite volume scheme and a 4-stage Runge-Kutta method. The control methodology for plume-afterbody interactions is to use a perforated wall attached at either the nozzle exit or the edge of the missile base. The Effect of porous wall length on plume interference is also investigated The computational results show the main effect of the porous extension on plume-afterbody interactions is to restrain the plume from strongly underexpanding during a change in flight conditions. With control, a change in porous extension length has no significant effect rut plume interference.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.1
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• pp.12-20
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• 2002

An integrated analysis of kerosine/LOX based KSR-III rocket body/plume flowfield has been performed. The analysis has been executed employing three kind of gas thermo-chemical models including calorically perfect gas, multiple species chemically reacting gas, and chemically frozen gas models and their effect on rocket flowfield has been accessed to provide the most appropriate gas thermo-chemical model which meets a specific purpose of performing rocket body and plume analysis. The finite-rate chemically reacting flow solution exhibited higher temperature throughout the flowfield than other gas models due to the increased combustion gas temperature caused by the chemical reactions within the nozzle. All the reactions were dominated only in the shear layer and behind the barrel shock reflection region where the gas temperature is high and the effect of finite-rate chemical reactions on the flowfield was found to be minor. However, the present plume computation including finite-rate chemical reactions revealed major reactions occurring in the plume and their reaction mechanisms and as well.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.254-257
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• 2011

Two types of thrusters(Descent Control Thruster (DCT) for reducing landing speed and Attitude Control Thruster (ACT) for attitude control) are mounted on the propulsion system of Ground test model lunar lander. In this paper, plume impingement effect and ground effect between DCT Modules are analyzed using numerical method when the impact occurred close to the ground.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.399-402
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• 2005

The present numerical study describes the flow physics on the interaction between the supersonic freestream and jet plume. The compressible flow past a simplified afterbody model with a sonic nozzle is investigated using mass-averaged Navier-Stokes equations, discretized by a fully implicit finite volume scheme, and the standard $k-{\omega}$ turbulence model. The results obtained through the present study are discussed specifically regarding the effect of the plume pressure ratio, freestream Mach number and base dimensions on the location of the plume-induced shock wave generated on the afterbody by the underexpansion of the jet plume.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.95-98
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• 2003

The physics of the plume-induced shock and separation particulary at a high plume to exit pressure ratio and supersonic speeds up to Mach 3.0 with aid without a passive control method, porous extension, were studied using computational techniques. Mass-averaged Navier-Stokes equations with the RNG k-$\varepsilon$ turbulence model were solved using a fully implicit finite volume scheme and a 4-stage Runge-Kutta method. The courol methodology for plume-afterbody interactions is to use a perforated wall attached at either the nozzle exit or the edge of the missile base. The Effect of porous wall length on plume interference is also investigated. The computational results show the main effect of the porous extension on plume-afterbody interactions is to in the plume from strongly underexpanding during a change in flight conditions. With control, a change in porous extension length has no significant effect on plume interference.

• Journal of Welding and Joining
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• v.17 no.1
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• pp.71-76
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• 1999

The real-time holographic interferometer with digital high-speed camera is applied to the experimental study of laser induced plasma/plume in pulsed Nd:YAG laser welding. A pulsed Nd:YAG laser with 1.2 kW average power is applied to generate laser induced plume. The recording speed of the high-speed camera is 3,000 f/s. The high speed photographs of weld plume without another visualization method, are compared with the visualization photographs with holographic interferometer. The radiation intensity from the laser induced plume is recorded by the high speed photographs, which fluctuated during laser radiation and disappeared after laser end. The density distribution of the plume is recorded by the holographic visualization method. The experimental results show the process of generation of the laser induced plasma/plume, and give the feasibility of quantitative measurement of laser induced plume in laser welding.