• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.74-87
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• 2015

A numerical parametric study has been accomplished to figure out the effect of grille shape built in a small passenger car on the aerodynamic performance such as drag and mass flow rate through CRFM(Condenser Radiator Fan Module). Three grille opening parameters and three grille mesh parameters are selected and adopted to a simple shape passenger car model. This research will provide a design guideline for grille opening geometry and mesh shape in the grille. FLUENT, which is very well known commercial code, hires k-${\epsilon}$ turbulence model at the driving speed of 110km/h with moving wall boundary condition. A porous media condition is prepared to estimate the pressure drop amount through CRFM parts.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.94-100
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• 2005

This paper describes the changes of Shinkansen vehicles' nose shape by increasing train speed and according to the stream of time. As the speed increases, the length of the nose trends to lengthen longer. But the nose length does not increase as speed improves by optimized nose shape to reduce aerodynamic drag and micro-pressure wave in tunnels. Shinkansen vehicles nose shape can be classified into Advanced paraboloid type, Sharp-nosed type, Organic double-edged type and Flat-nosed type. In addition, it trends to be diversified and characterized more and more. In the near future, nose designs will be emphasized by the design concept including identity of each JR company based on optimized aerodynamic shape.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.499-505
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• 2000

The shape of the KHST, and of the power car in particular, is largely determined by aerodynamic considerations. At high speeds, air resistance accounts for the major part of overall resistance to forward motion. Further points to be considered are environmentally undesirable acoustic phenomena and pressure waves. Minimizing power requirements and environmentally-unfriendly noise and pressure waves are thus major objectives in the development of the KHST. When deciding on the aerodynamic design of the power car, the entire train set has to be taken into consideration. This paper describes the design process and results about the front shape of the KHST.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.115-120
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• 1999

The shape of the KHST, and of the power car in particular. is largely determined by aerodynamic considerations. At high speeds, air resistance accounts for the major part of overall resistance to forward motion. Further points to be considered are environmentally undesirable acoustic phenomena and pressure waves. Minimizing power requirements and environmentally-unfriendly noise and pressure waves are thus major objectives in the development of the KHST. When deciding on the aerodynamic design of the power car, the entire train set has to be taken into consideration. This paper describes the design process and results about the front shape of the KHST.

• The KSFM Journal of Fluid Machinery
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• v.3 no.4 s.9
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• pp.30-37
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• 2000

Several reverse design methods are developed and applied to the suction or pressure surface for finding design values of blade geometry for a given axial turbine blade. Re-designed blade profiles using shape parameters are compared with measured blade data. Essential shape parameters for blade design are induced by the procedure of reverse design for best fitting. Characteristics of shape parameters are evaluated through the system design method and restriction conditions of structural stability or aerodynamic flow loss. Some of shape parameters i.e blade radius or exit blade angle etc., are classified to weakly adjustable shape parameters, otherwise strongly adjustable shape parameters which would be applied for controlling blade shape. Average deviation values between the measured data and re-designed blade using shape parameters are calculated for each design method. Comparing with the average deviation for a given blade geometry, minimum shape parameters required to design a blade geometry are obtained.

• Wind and Structures
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• v.18 no.2
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• pp.135-154
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• 2014

Aerodynamic characteristics of crescent and D-shape bundled conductors were measured by high frequency force balance technique in the wind tunnel. The drag and lift coefficients of each sub-conductor and the whole bundled conductors were presented under various attack angles of wind. The galloping possibility of bundled conductors is discussed based on the Den Hartog criterion. The influence of icing thickness, initial ice accretion angle and sub-conductor on the aerodynamic properties were investigated. Based on the measured aerodynamic force coefficients, a computationally efficient finite element method is also implemented to analyze galloping of iced bundled conductors. The analysis results show that each sub-conductor of the bundled conductor has its own galloping feature due to the use of aerodynamic forces measured separately for every single sub-conductors.

• Journal of Aerospace System Engineering
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• v.4 no.2
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• pp.26-31
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• 2010

Reduction of the aerodynamic drag is one of the most hot issues of car industries. Many researchers have studied in the area of drag reduction methodology using experimental tools or numerical tools. In general, car shape design is the main focus to reduce the drag in aerodynamic research area. However, not many people have studied the aerodynamic interference between running cars to figure out the drag variation. In this research, the aerodynamic interference between two running cars have been analyzed by using numerical tools, FLUENT 6.2. Several different models of cars and two different distances between two running cars are considered.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.31-39
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• 1996

The effect of rear-spoiler attached at rear end of automobile trunk on the aerodynamic characteristics of a MIRA reference car model was experimentally investigated. For different shapes and positions(G/H) of the rear-spoiler, the aerodynamic forces on the automobile were measured at various flow speed(ReL). The effect of rear-spoiler on the wake structure behind the automobile was also investigated using flow visualization and hot-wire anemometer. The rear-spoiler modifies the near wake structure and decreases aerodynamic drag and increases driving stability compared with those of the conventional automobile without rear-spoiler. From the experimental results, rear-spoiler of airfoil shape installed at the position of G/H=0.084 shows the best aerodynamic performance.

• Journal of Aerospace System Engineering
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• v.3 no.3
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• pp.7-12
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• 2009

Reduction of the aerodynamic drag is one of the most hot issues of car industries. Many researchers have studied in the area of drag reduction methodology using experimental tools or numerical tools. In general, car shape design is the main focus to reduce the drag in aerodynamic research area. However, not many people have studied the aerodynamic interference between running cars to figure out the drag variation. In this research, the aerodynamic interference between two running cars have been analyzed by using numerical tools, FLUENT 6.2. Several different models of cars and two different distances between two running cars are considered.

• Journal of the Korea Society for Simulation
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• v.29 no.3
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• pp.49-55
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• 2020

A goal of improving projectile is to increasing achievable range. The shape of a projectile is generally selected on the basis of combined aerodynamics and structural considerations. The choice of body, nose and boattail shape has a large effect on aerodynamic design. One of the main design factors that affect projectile configuration is aerodynamic drag. The aerodynamic drag refers to the aerodynamic force that acts opposite to the relative motion of a projectile. An investigation was made to predict the effects of nose, boattail and body shapes on the aerodynamic characteristics of projectiles using a semi-empirical technique. A parametric study is conducted which includes different projectile geometry. Performance predictions of achievable range are conducted using a trajectory simulation model. The potential of extending the range of a projectile using optimization of projectile configuration is evaluated. The maximum range increase is achieved due to the combination of optimal body shapes.