• Transactions of the Korean Society of Automotive Engineers
• /
• v.6 no.4
• /
• pp.86-100
• /
• 1998

The impingement of the fuel spray on the wall within the combustion chamber in compact high-pressure injection engines and on the intake port wall in port-fuel-inje- ction type engines is unavoidable. It is important to understand the characteristics of impinging spray because it influences on the rate of fuel evaporation and droplet distrib- ution etc. In this study, the numerical study for the characteristics of spray/wall interaction is performed to test the applicability and reliability of spray/wall impingement models. The impingement models used are stick model, reflect model, jet model and Watkins and Park's model. The head of wall-jet eminating radilly outward from the spray impingement site contains a vortex. Small droplets are deflected away from the wall by the stagnation flow field and the gas wall-jet flow. While the larger droplets with correspondingly higher momentum are impinged on the wall surface and them are moved along the wall and are rolled up by wall-jet vortex. Using the Watkins and Park's model the predicted results show the most reasonable trend. The rate of increase of spread and the height of the developing wall-spray is predicted to decrease with increased ambient pressure(gas density).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.969-973
• /
• 2007

The heavy-weight floor impact sound field of the receiving room in a testing building with bearing wall structure was investigated using bang machine and impact ball. The sound field was investigated through the impact sound pressure level distribution by the field measurement and computational analysis. Predicted sound field using the computational analysis agree with measurement result in the low frequency band. Result shows that standard deviations of the single number rating value are about 2dB in each impact source. Particularly, impact sound pressure level at 120cm height in 63Hz octave band was 5dB lower than spatial averaging value. It was found that receiving positions in the ministry of construction and transportation notice should be reconsidered.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.41 no.1
• /
• pp.1-8
• /
• 2004

We developed a new PDP gray scale implementation method on the basis of the quantized memory addressing(QMA) principle. We defined three wall charge states; 'fully-on', 'off', and 'half-on', by controlling the width of address pulses. With these three wall charge state, we were able to express 255 level gray scale with only 7 sub-fields. Furthermore, in contrast to the conventional driving methods, the sub-field combinations for any two adjacent gray levels differ by only 1 sub-field, at worst, and therefore, eliminate the dynamic false contours. Since this method use 7 sub-field, the sustain discharge Period is increased by more than $70\%$ compared to the 12 sub-field method which reduces the dynamic false contours.

• Korean Institute of Interior Design Journal
• /
• v.22 no.3
• /
• pp.33-42
• /
• 2013

The purpose of this study was to analyze the design trend of the vertical garden design in the indoor space through the examples of green wall in the lobby space. For the analysis, this study looks into the 'Guide for the Building Greening System' to understand the technical consideration for the green wall. After that, the key design elements was drawn from existing green walls through the literature review and field survey and field-survey. The study picked six green walls which was completed after 2000 in the lobby space in Seoul. The major findings of this study were as follows: First, the design factors mainly depend on the plant selection, which leads to the outlook and texture of the vertical walls. The texture is expressed by the two-dimensional or three-dimensional planting methods which is related to the selection of plant species. Second, the vertical walls in the lobby area should be planned for the function of space which could be transition, human traffic, mood and attraction. Third, the vertical wall should be integrated with the surroundings in order to reinforces the dynamic or static space experience.

• Journal of the Korean housing association
• /
• v.27 no.5
• /
• pp.25-35
• /
• 2016

he objective of this study was to investigate home network systems presently applied in multi-housing complexes and resident's usage to improve the utilization of these systems and services as well as maintenance methods. Subjects were 27 housing complexes equipped with home network systems in west Pangyo area. The investigation methods of communal network systems were observed and photographed. Unit systems were investigated through photography, interviews, and observation focusing on the utilization of Wall-Pads by visiting one unit of each housing complex. The results are as follows: (1) Most housing complexes that we investigated were built with high-grade IT infrastructure. Also, remote meter reading, electronic security, vehicle access, and building access systems were established. Wall-Pads with similar functions were installed in 23 housing complexes, excluding private rental housing complexes. (2) Even though people were well aware of the need for common systems within their housing complexes, only 10~20% of Wall-Pad menus were used. (3) Low utilization rates of home network stem from Wall-Pad menus which were user-unfriendly, and a lack of user training for the complex's common system and unit system. Therefore, to promote active use of home network systems, the systems must be diversified in accordance with user characteristics. In addition, the Wall-Pad menus should be reorganized to be user-friendly.

• Korea-Australia Rheology Journal
• /
• v.19 no.3
• /
• pp.147-156
• /
• 2007

The orientation and deformation of polymer chains in a confined channel flow has been investigated. The polymer chain was modeled as a Finitely Extensible Nonlinear Elastic (FENE) dumbbell. The Brownian configuration field method was extended to take the interaction between the flow and local chain dynamics into account. Drag and Brownian forces were treated as anisotropic in order to reflect the influence of the wall in the confined flow. Both Poiseuille flow and 4 : 1 contraction flow were considered. Of particular interest was molecular tumbling of polymer chains near the wall. It was strongly influenced by anisotropic drag and high shear close to the wall. We discussed the mechanism of this particular behavior in terms of the governing forces. The dumbbell configuration was determined not only by the wall interaction but also by the flow type of the geometric origin. The effect of extensional flow on dumbbell configuration was also discussed by comparing with the Poiseuille flow.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.4
• /
• pp.894-903
• /
• 2014

Insertion loss prediction of large acoustical enclosures using Statistical Energy Analysis (SEA) method is presented. The SEA model consists of three elements: sound field inside the enclosure, vibration energy of the enclosure panel, and sound field outside the enclosure. It is assumed that the space surrounding the enclosure is sufficiently large so that there is no energy flow from the outside to the wall panel or to air cavity inside the enclosure. The comparison of the predicted insertion loss to the measured data for typical large acoustical enclosures shows good agreements. It is found that if the critical frequency of the wall panel falls above the frequency region of interest, insertion loss is dominated by the sound transmission loss of the wall panel and averaged sound absorption coefficient inside the enclosure. However, if the critical frequency of the wall panel falls into the frequency region of interest, acoustic power from the sound radiation by the wall panel must be added to the acoustic power from transmission through the panel.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.5-6
• /
• 2010

In this study, assuming that there is a diagonal uniaxial compression field in combination with triangular homogeneous stress fields in the cracked concrete wall and a tensile stress of a steel plate occurs in the perpendicular to the direction of the diagonal compression field, an ultimate shear strength of a slender composite shear wall is estimated.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.5
• /
• pp.39-45
• /
• 2006

A field instrumentation for a recycled waste concrete geobag wall was performed to investigate the performance of the geobag wall, and uniaxial compression tests for a recycled waste concrete geobag were executed in laboratory. The strength of a recycled waste concrete geobag, the lateral earth pressure of a geobag wall, the horizontal deflection of a geobag wall, and the deformation of a backfill in geobag wall are mainly evaluated in this study. Based on the results of analysis on the measurements, it was found that the geobag wall displacement was within the recommendation for mechanically stabilized earth walls. It was also found that the use of a recycled waste concrete in geobag wall provides economical benefit, construction easiness, and good performance.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.2297-2302
• /
• 2007

Numerical simulations are conducted to analyze conjugate heat transfer characteristics in a ribbed channel. In this simulation, the effects of Reynolds number and heat capacity of the solid channel wall on convective heat transfer are observed in the turbulent flow regime. In the case of the conducting wall against isothermal wall, the relative ratio of the thermal resistance between the solid wall and the flow field varies with Reynolds number. Thus the characteristics of the conjugate heat transfer are changed with the Reynolds number. Heat capacity ratio affects the temperature fluctuation inside solid wall. The temperature fluctuation inside the solid wall decreases with increasing the heat capacity of the solid wall so that the convective heat transfer increases. When the thermal conductivity ratio is smaller than 10, the effects of flow characteristics on heat transfer are changed.