• Journal of Ocean Engineering and Technology
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• v.20 no.1 s.68
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• pp.20-25
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• 2006

This paper deals with the design and aerodynamic analysis of a so-called 'ring-type' impulse turbine for wave energy conversion. Numerical analysis was performed using the CFD cock, FLUENT. The main idea of the proposed turbine rotor was to minimize the adverse effect of tip clearance of the turbine blade; the design was borrowed from a ducted propeller with connected ring tip for special purpose marine vehicles. Results show that the efficiency increases up to $10\%$, depending on flaw coefficient, with the higher flaw coefficient yielding better efficiency. Decrease of input coefficient CA was the main reason for higher efficiency. Performance of ring-type rotor at various design parameters, as well as flaw conditions, was investigated, and the advantages and the disadvantages of the present impulse turbine were also discussed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.8
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• pp.72-81
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• 2004

A Wind tunnel test for a high speed ground vehicle was conducted to investigate the aerodynamic interactions between the vehicle and a solid channel. The free stream velocity was 30m/see and Reynolds number per unit length was $3.1{\times}10^5/m$. Experimental devices such as a variable channel ground and guide way were used for the test. As the vehicle was close to the channel ground and guide way, lift was significantly increased, drag was slightly decreased and pitching moments were restricted to augment static stability. Using smoke-wire, flow visualization was made to confirm these results by comparing the channel and non-channel flow characteristics of the vehicle. Under the influence of the channel ground and guide way, the flow beneath the vehicle was not discharged outside wing end plates, which was the major reason of the increase in lift of the vehicle.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.6
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• pp.483-488
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• 2007

The aerodynamic characteristics of FAST(Future Air Speed Transit) combined the body with tandem wing flying over nonplanar ground surface are investigated by using a boundary element method. To validate the present method, results of the present analysis are compared with the experiment and other numerical results. The arrangement of the tandem wing is determined to secure sufficient aero-levitation force and the stability through the analysis of the aerodynamic characteristics of the FAST. The FAST has the maximum lift characteristics when the tandem wing with lower endplate is located at the front side and the rear side of the body. The stability of the FAST can be secured by using the flaperon of the tandem wing.

• The Journal of the Korean bone and joint tumor society
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• v.12 no.1
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• pp.83-88
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• 2006

Osteochondroma is a hyperplasic bony lesion caused by subperiosteal displacement of physeal cartilages, and the most common benign bone tumor. Osteochondromas rarely cause vascular complications, but when encountered, acute ischemia, phlebitis, and arterial puncture are the most common. They are caused by the mass effect or by the sharp end of the tumor. Deep vein thrombosis may be caused by impaired venous blood flow or a hypercoagulable blood state, but sometimes no predisposing cause can be found. We experienced a patient with deep vein thrombosis caused by the mass effect of an asymptomatic osteochondroma, and treated him successfully by excising the osteochondroma and performing a saphenous vein graft after resecting obstructed vein.