• 한국전산유체공학회:학술대회논문집
• /
• 2010.05a
• /
• pp.308-314
• /
• 2010

In this study, NASA test model with four cruciform fins is utilized to validate the in-house code. Sur face pressure distribution and aerodynamic coefficients are compared with experimental data. Through extensive validation work, it is verified that the code has capability to predict aerodynamic characteristics of missile configuration. In inviscid analysis through a relatively low computational time, analysis result close to experimental data can be confirmed. However, at high angle of attack more than 20 degree, the accuracy of analysis is gradually decreased due to massive separation. In addition, it has been seen that Reynolds number, turbulence model and numerical method have effects on body vortices and aerodynamic characteristics.

• Proceedings of the KSME Conference
• /
• 2002.08a
• /
• pp.87-90
• /
• 2002

Computational study has been undertaken to investigate the aerodynamic influence of side jet on a supersonic missile and to find a similarity condition between the flight condition and the wind tunnel testing. Tasks were performed to validate the existing Raytheon test body with side jet, to simulate the flow inside the supersonic wind tunnel, and to compare the flow fields between the missile in free flight and that in the wind tunnel. Then sub-scale model of body-tail configuration was analyzed to estimate the influence of the side jet on the missile components. It Is found that the influence of side Jet is not as significant on the tail region as on the body surface and a simple algebraic formula for aerodynamic coefficients accounting for the side jet as a point force may be cautiously utilized in setting up control logic.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.2
• /
• pp.169-173
• /
• 2011

Crash box is introduced to vehicle design to improve the impact performance and reduce the damage of vehicle body at impact speed. The crash box behind bumper can absorb impact energy effectively to improve vehicle safety. Repair cost at collision accident can be cut down by use of this box. The configuration of car body must be designed by considering the characteristic of material due to the deformation of car body happened at impact. Many papers have been published about material of crash box all over the world. The study of crash box with tube expansion type has been going on Korea. This study is done by the simulation analysis about front collisions against 5 kinds of aluminum crash boxes with the basic structure of square section.

• 한국전산유체공학회:학술대회논문집
• /
• 2002.05a
• /
• pp.41-46
• /
• 2002

Computational study has been undertaken to investigate the aerodynamic influence of side jet on a supersonic missile and to find a similarity condition between the flight condition and the wind tunnel testing. Tasks were peformed to validate the existing Raytheon test body with side jet, to simulate the flow inside the supersonic wind tunnel, and to compare the flow fields between the missile in free flight and that in the wind tunnel. Then sub-scale model of body-tail configuration was analyzed to estimate the influence of the side jet on the missile components. It is found that the influence of side jet is not as significant on the tail region as on the body surface and a simple algebraic formula for aerodynamic coefficients accounting for the side jet as a point force may be cautiously utilized in setting up control logic.

• Smart Structures and Systems
• /
• v.21 no.2
• /
• pp.225-234
• /
• 2018

E-Health allows you to supersede the central patient wireless healthcare system. Wireless Body Sensor Network (WBSN) is the first phase of the e-Health system. In this paper, we aim to understand e-Health architecture and configuration, and attempt to minimize energy consumption and latency in transmission routing protocols during restrictive latency in data delivery of WBSN phase. The goal is to concentrate on polling protocol to improve and optimize the routing time interval and schedule communication to reduce energy utilization. In this research, two types of network models routing protocols are proposed - elemental and clustering. The elemental model improves efficiency by using a polling protocol, and the clustering model is the extension of the elemental model that Destruct Supervised Decision Tree (DSDT) algorithm has been proposed to solve the time interval conflict transmission. The simulation study verifies that the proposed models deliver better performance than the existing BSN protocol for WBSN.

• Advances in aircraft and spacecraft science
• /
• v.3 no.3
• /
• pp.259-269
• /
• 2016

In this work results from an underwater experiment on flow-induced noise in the interior of a towed body generated from a surrounding turbulent boundary layer are presented. The measurements were performed with a towed body under open sea conditions at towing depths below 100 m and towing speeds ranging from 2.4 m/s to 6.2 m/s (4 kn to 12 kn). Focus is given in the experiments to the relation between (outer) wall pressure fluctuations and the (inner) hydroacoustic near-field on the reverse side of a flat plate. The plate configuration consists of a sandwich structure with an (thick) outer polyurethane layer supported by an inner thin layer from fibre-reinforced plastics. Parameters of the turbulent boundary layer are estimated in order to analyse scaling relations of wall-pressure fluctuations, interior hydroacoustic noise, and the reduction of pressure fluctuations through the plate.

• 한국전산유체공학회:학술대회논문집
• /
• 2008.03b
• /
• pp.456-459
• /
• 2008

In the field of yarn dyeing, the most generally employed method is a type of package dyeing which uses a package cheesesstacked on a spindle made of a perforated tube. Spindles up to now, have been designed without considering the characteristics of dyeing liquid, focusing only on the geometric configuration which cause many problems such as lack of level dyeing. To improve the level dyeing and find the appropriate spindle configuration for the most effective dyeing process, this study examines the spindle flow-field in detail, using a computational method. Flow characteristics inside the spindle have been investigated with varying in porosity, porous diameter and the velocity of the flow. The results show that the total pressure of the flow through the spindle is used to overcome body force. The characteristics of the flow from the porous spindle could also be observed. Based on the results from this study, an effective spindle configuration for level-dyeing has been proposed.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.13 no.4
• /
• pp.8-18
• /
• 2005

Pedestrians involved in traffic accidents manifest unique trajectory characteristics depending on the collision speed, vehicle configuration, and pedestrian postures. However, the existing analytical models for pedestrian movements do not fully include the rotational characteristics of the pedestrians because they assume a two dimensional parabolic trajectory. This faulty assumption in the development of these models limits their applicability and reliability This study investigated the pedestrians movement at collision by computer simulation. The simulations are carried out by using HADYMO, which is a special simulation software system for dynamic movement analysis. Vehicles and pedestrians are modeled and verified via real crash worthiness experiments. Simulations are performed for various collision speeds, vehicle configuration, and pedestrian postures. Since the simulation uses multi-body dynamics, It can express irregular phenomena of the bodies quite well. The results can be exploited for vehicle design and traffic accident reconstruction.

• Journal of the Korean Society of Costume
• /
• v.60 no.10
• /
• pp.133-145
• /
• 2010

The study used four basic formats classified based on the four principles on costumes discussed in the paper 'Human Beings and Arts Phenomena' by Oskar Schlemmer who studied the relationships between stage space and the human body as an analysis tool with regard to analyses on the abstraction of human body in contemporary dance costume. Abstraction of human body expressed in costume for contemporary dance is as follows: Expansions caused by unclear boundary between spaces and costumes, and the principles of three-dimensional abstract spaces based on a geometric cube change heads, trunks, arms and legs to achieve expansions. Similar mechanical shape is a type of shape made in a succession of functional principles of human body in relationships with spaces. As mechanical mechanism is added to the geometric transformation of a specific part of human body, mechanicalness is contained in it. Motion organisms are geometric simplification of moving traces in a space based on conversion into mechanical organisms based on principles of motion, and as mechanical rotation, consecutive speed caused by refraction and directionality are suggested, mobility is achieved. Immaterial shape is based on change into a metaphysical form, and it is converted into animals, plants or a third life that symbolize body parts. It has metaphysical significance in each body part and extends sensibility. As a result of the study, development into abstract succession and a techno art mode has been confirmed. Combination of geometric cubic figures with the organic human body and configuration of the human body pursued by Oskar Schlemmer's geometric abstraction through the proactive accommodation of mechanical aesthetics has been succeeded and expressed in the contemporary dance costumes.

• Journal of Ocean Engineering and Technology
• /
• v.24 no.5
• /
• pp.16-21
• /
• 2010

During the loading/offloading operation of a liquefied natural gas carrier (LNGC) that is moored in a side-by-side configuration with an offshore plant, sloshing that occurs due to the partially filled LNG tank and the interactive effect between the two floating bodies are important factors that affect safety and operability. Therefore, a time-domain software program, called CHARM3D, was developed to consider the interactions between sloshing and the motion of a floating body, as well as the interactions between multiple bodies using the potential-viscous hybrid method. For the simulation of a floating body in the time domain, hydrodynamic coefficients and wave forces were calculated in the frequency domain using the 3D radiation/diffraction panel program based on potential theory. The calculated values were used for the simulation of a floating body in the time domain by convolution integrals. The liquid sloshing in the inner tanks is solved by the 3D-FDM Navier-Stokes solver that includes the consideration of free-surface non-linearity through the SURF scheme. The computed sloshing forces and moments were fed into the time integration of the ship's motion, and the updated motion was, in turn, used as the excitation force for liquid sloshing, which is repeated for the ensuing time steps. For comparison, a sloshing motion coupled analysis program based on linear potential theory in the frequency domain was developed. The computer programs that were developed were applied to the side-by-side offloading operation between the offshore plant and the LNGC. The frequency-domain results reproduced the coupling effects qualitatively, but, in general, the peaks were over-predicted compared to experimental and time-domain results. The interactive effects between the sloshing liquid and the motion of the vessel can be intensified further in the case of multiple floating bodies.