• Journal of computational fluids engineering
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• v.15 no.3
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• pp.32-38
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• 2010

Aerodynamic design of the vane type multi-function probe was tried by using CFD and wind tunnel test for the MALE UAV and small business jets. The present multi-function probe can measure total pressure, static pressure and angle of attack by using rotating vane. Therefore, major performances are determined by aerodynamic characteristics of vane. In order to design the sensor compatible to the requirement, aerodynamic characteristics of sensors were investigated by using CFD and dynamic response analysis was also performed for transient performance. The final aerodynamic performance was measured by the wind tunnel test at Aerosonic and the results were compared with the present design. The results showed that the aerodynamic design using the CFD can be successfully used for the design of vane type multi-function air data sensor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3518-3524
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• 2015

Spatial and time variation of the precipitation in Korea is high, therefore, more than 2/3 of the annual precipitation is concentrated during the rainy season. Climate change also causes the intensive rainfall in the area of dense population, thus the occurrence frequency of the heavy flood in the impervious area has been increased. Therefore, the structural food mitigation measures such as the construction of the higher design frequency stormwater pipes, pumping stations, and/or detention ponds. The flood bypass tunnel or retention storage is also one of the efficient structures to mitigate flood damage in the urban area. However, the economic feasibility has been controversial because the flood bypass tunnel might be used once or twice a year. To solve the problem, the multi-functional tunnel for the urban traffic and flooding bypass has been considered. In this study, the design criteria of the road and water tunnel has been analysed and the composite design criteria is proposed for the multi-functional tunnel which is expected to be constructed.

• Tunnel and Underground Space
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• v.33 no.4
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• pp.255-264
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• 2023

As the demand for urban underground space increases recently, urban tunnel planning is actively progressing. In the urban area, a underground station is planned in consideration of the living environment of residents, and 2-arch tunnel is applied for the stability of existing structures and reduction of environmental damage. However, since the depth of weak rock mass is deeply distributed in the urban area due to severe weathering, careful planning is required to secure tunnel stability. In addition, if TBM mechanical excavation is applied as the main tunnel excavation method considering the composite ground in urban area, the construction connectivity with the 2-arch tunnel of the NATM concept may be deteriorated. In this study, the design case of applying TBM pre-excavation type 2-arch tunnel for the first time in Korea was mainly described. The main considerations for the segment design of TBM pre-excavation type 2-arch tunnel were explained for side tunnels. Also, a stability analysis was conducted to verify the effectiveness and adequacy of the TBM pre-excavation type 2-arch tunnel.

• Explosives and Blasting
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• v.23 no.4
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• pp.19-29
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• 2005

Blasting design methods applied in Korea were originally made for foreign rock conditions and blasting environments. Therefore, it has not been fully fitted to the Korean rock renditions. Since 1998, several studies for the automated pattern design of tunnel blasting have been carried out. As the result, a new blasting design method which can settle the problems was developed. Through it is more complex than prior method, it call provide a variety of advantages for us. Through the method, it is possible to vary charge weight according to the changing advance. It ran also be applied to the various design for contour holes. In this study, the newly developed method is introduced.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.4
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• pp.328-336
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• 2008

The shock tunnel as a hypersonic ground test facility was designed, constructed and its performance test was conducted to reproduce the high speed flow which the hypersonic propulsion system is encountered. The design points were understood and the conceptual design was completed using the quasi one dimensional operation analysis code. After that, the specific performance and compartment design were completed using CFD simulation as the part analysis. The facility was then constructed according to those design results and the performance test was conducted for various operation conditions. In this paper, we suggested the compartment design method using CFD analysis, construction process and various performance test results in detail.

• The Journal of the Acoustical Society of Korea
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• v.32 no.3
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• pp.237-246
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• 2013

This paper proposes a hydrophone array design optimization technique for cavitation tunnel noise measurements. The optimization technique comprises of design parameters, an objective function and an optimization algorithm. The design parameters are defined for circular, spiral and multi-spiral arrays. The objective function is defined so as to consider the mainlobe beamwidth and the maximum sidelobe level simultaneously. A global optimization scheme is applied to the array design using very fast simulated reannealing (VFSR). After applying the optimization technique to arrays respectively, the peak sidelobe level and the mainlobe beamwidth of optimum arrays are analyzed. Finally the array patterns considering multiple reflections in the cavitation tunnel are evaluated to validate the proposed method.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.185-192
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• 1999

This paper presents the results of a parametric study on the behavior of tunnel face reinforced with horizontal pipes. A three-dimensional finite element model was adopted in this study to capture the three-dimensional nature of tunnel face behavior under various boundary conditions. A parametric study was peformed on a wide range of boundary conditions with emphasis on the effect of reinforcing layouts on the deformation behavior of tunnel face. The results of analysis such as tunnel face deformation behavior under various conditions were thoroughly analyzed, and a database for the behavior of tunnel face under different reinforcing conditions was established for future development of a semi-empirical design/analysis method for the tunnel face reinforcing technique. The results indicated that there exits an optimum reinforcing layout for a given tunnel condition, which must be selected with due consideration of tunnel geometry and ground condition.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.417-422
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• 2005

The appropriate ventilation system in vehicular tunnel should be the most economical solution with regard to both construction and maintenance. The damages on tunnel lining was affected by formula of ventilation system in long vehicular tunnel. In this study, carbonation, one of main experimental items in precision safety diagnosis, was analyzed by contouring damage area with ventilation system. Considerations of carbonation were also given to the design and maintenance which manage the long-term safety in tunnel.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.87-92
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• 2000

In excavation of tunnels especially located in shallow depth, it is not rare to meet geological change in excavation progress worse than expected in the initial design stage. This paper present a case study on the re-design of excavation and support system of a shallow tunnel under construction where it meets the unexpected bad geological condition during excavation. The detailed geological investigation shows that the rock mass is heavily weathered and fractured with RMR value less than 20. Considering this geological condition, the design concept is focused on the reinforcement of the ground preceding the excavation of tunnel. Two design patterns, LW-grouting & forepoling with pilot tunnelling method and the steel pipe reinforced grouting method, are suggested. Numerical analysis by FLAC shows that these two patterns give the tunnel and roof ground stable in excavation process while the original design causes severe failure zone around the tunnel and floor heaving. In point of the mechanical stability and the degree of construction, the steel pipe reinforced grouting technique proved to be good for the reinforcement of heavily fractured rock mass in tunnelling. This assessment and design process would be a guide in the construction of tunnels in heavily weathered and fractured rock mass situation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.4
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• pp.321-327
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• 2008

The shock tunnel as a hypersonic ground test facility was designed, constructed and its performance test was conducted to reproduce the high speed flow which the hypersonic propulsion system is encountered. The design points were understood and the conceptual design was completed using the quasi one dimensional operation analysis code. After that, the specific performance and compartment design were completed using CFD simulation as the part analysis. The facility was then constructed according to those design results and the performance test was conducted for various operation conditions. In this paper, we suggested the design method of hypersonic shock tunnel including the conceptual and performance design using theoretical analysis and the quasi 1D Multi-species computational fluid dynamics code.