• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.7
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• pp.12-17
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• 2006

Longitudinal static stability and steady aerodynamic characteristics of wings flying over nonplanar ground surfaces (rail and channel) are investigated using the boundary-element method. For a channel with it's fence higher than the wing height, the lift and the nose-down pitching moment increase as the gap between the wingtip and the fence decreases. For a rail with it's width wider than the wing span, the lift and the nose-down pitching moment increase as the rail height decreases. Longitudinal static stability of a single wing flying over nonplanar surfaces is worse than the case of the flat ground. In case of tandem wings, longitudinal static stability of the wings flying over the channel is better than the case of the flat ground. It is believed that the present results can be applied to the conceptual design of high-speed ground transporters.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.3
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• pp.163-172
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• 2017

Porous insulation have been frequently used in a number of industries by minimizing thermal insulation space because of excellent performance of their thermal insulation. This paper devices an effective thermal conductivity prediction model. First of all, we perform literature survey on traditional effective thermal conductivity prediction models and compare each other model with heat transfer experimental results. Furthermore this research defines advanced effective thermal conductivity prediction models model based on heat transfer experimental results, the Zehner-Schlunder model. Finally we verify that the newly defined effective thermal conductivity prediction model has better performance prediction than other models. Finally, this research performs a transient heat transfer analysis of thermal protection system with a porous insulation using the finite element method and confirms validity of the effective thermal conductivity prediction model.