• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.1
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• pp.82-93
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• 2002

The effects of the interaction between the flow and temperature field and a boundary layer due to a variety of the height of a vortex generator are experimentally investigated. The test facility consists of a boundary-layer wind tunnel with the vortex generator protruding from the bottom surface. In order to control the strength of the longitudinal vortices, the angle of attack and the spacing distance of the vortex generator are 20 degree and 40 mm, respectively. The height of the vortex generator (H) is 15 mm, 20 mm and 30 mm and the cord length of it is 50 mm. Three-component mean velocity measurements are made using a 5-hole probe system and the surface temperature distribution is measured by the hue capturing method using thermochromatic liquid crystals. By using the method mentioned above, the following conclusions are obtained from the present experiment. The boundary layer is thinned in the downwash region where the strong downflow and the lateral outflow of the boundary layer fluid occur and thickened in the upwash re,3ion where the longitudinal vortex sweeps low momentum fluid away from the bottom surface. In case that the height of the vortex generator increases, the averaged circulation and the maximum vorticity of the vortex pair decrease. The contours of the non-dimensional temperature show the similar trends fur all the cases (H=15 mm, 20 mm and 30 mm). The peak augmentation of the distribution of the local non-dimensional temperature occurs in the downwash region near the point of minimum boundary-layer thickness.

• Ocean and Polar Research
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• v.30 no.2
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• pp.129-140
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• 2008

As a preliminary effort to establish a data assimilative ocean forecasting system, we reviewed the theory of the Ensemble Kamlan Filter (EnKF) and developed practical techniques to apply the EnKF algorithm in a real ocean circulation modeling system. To verify the performance of the developed EnKF algorithm, a wind-driven double gyre was established in a rectangular ocean using the Regional Ocean Modeling System (ROMS) and the EnKF algorithm was implemented. In the ideal ocean, sea surface temperature and sea surface height were assimilated. The results showed that the multivariate background error covariance is useful in the EnKF system. We also tested the sensitivity of the EnKF algorithm to the localization and inflation of the background error covariance and the number of ensemble members. In the sensitivity tests, the ensemble spread as well as the root-mean square (RMS) error of the ensemble mean was assessed. The EnKF produces the optimal solution as the ensemble spread approaches the RMS error of the ensemble mean because the ensembles are well distributed so that they may include the true state. The localization and inflation of the background error covariance increased the ensemble spread while building up well-distributed ensembles. Without the localization of the background error covariance, the ensemble spread tended to decrease continuously over time. In addition, the ensemble spread is proportional to the number of ensemble members. However, it is difficult to increase the ensemble members because of the computational cost.

• 한국해양학회지
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• v.25 no.4
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• pp.161-181
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• 1990

A numerical model is established in order to simulate the storm surges which were observed in the seas around Korea during typhoon and winter storm periods. The typhoons are Brenda (1985), Vera (1986) and Thelma (1987). the winter storm period is January 1-6, 1986. The simulated surges for the typhoon periods show good agreements with the recorded ones for the periods at the Korean coasts, but those for the winter storm show fair agreements in general tendencies, not in details. The model simulation in open sea shows a positive sea level near the typhoon center and a native sea level behind the typhoon. the positive surge seems to be due to the low pressure near a typhoon center and the negative on due to the wind stresses of the typhoon. The negative sea level is usually in the form of an elongated gyre. In the gyre, there is a cyclonic circulation of sea water, in which the pressure gradient force induced by the circular depression of the sea surface is balanced by the Coriolis force in readjusting stage.

• The Journal of Internal Korean Medicine
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• v.15 no.2
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• pp.148-162
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• 1994

A Literature study was done for identifying the effects of Bloodletting on C.V.A. The major results of the study were as follows. 1. The frequency of points of Bloodletting on C.V.A. were in order Twelve well point, Ship son, Gold SalivaJade Fluid, Paekoe, Chungchung, Sugu, Sosang, Taechu, Wijung, Kwanchung, etc. 2. The frequency of meridians of Bloodletting on C.V.A. were in order Extra-point, Tongmaek-kyong, Su-gworum-Shimpo-Kyong, Susoyang-Samcho-Kyong, Sutaeum-Pye-Kyong, Choktaeyang-Panggwang-Kyong. ete. 3. The frequency of the site of points of Bloodletting on C.V.A. were in order four extremities, face, neck and head, etc. 4. The effects of Bloodletting on C.V.A. is clear away heat and alleviate pain, therapy for waking up a patient from unconsciousness, dredge the meridian passage, expel wind-evil and promote blood circulation, emergency treatment for collapse, etc, 5. The effects of Bloodletting on the early stage of C.V.A. were wake up the patient from unconsciousness by clearing away the heat and The effects of Bloodletting on sequence of C.V.A. were dredge the meridian passage, 6. The frequency of points and meridians of Bloodletting on Hemiplegia were in order Twelve well point, Kyonjong, Extra-point, Chok soyang-Tam-Kyong, etc. 7. The frequency of points and meridians of Bloodletting on Aphasia were in order Gold Saliva Jade Fluid, Amun, Extra-point, Tongmaek-Kyong, etc. 8. The frequency of points and meridians of Bloodletting on Quadriplegia were in order Ship son, Twelve well point, Koktaek, Wijung, Extra-point, Chok soyang-Tam-Kyong, etc. 9, The frequency of points and meridians of Bloodletting on Vertigo were in order Four Gods Cleverness, Tuyu. Chanjuk, Paekoe, Taeyang, Extra-point, Yang-Kyong, etc. 10. The frequency of points and meridians of Bloodletting on Headache were in order Taeyang, Paekoe, Taechu, Extra-point, Tongmaek-Kyong, Yang-Kyong, etc. 11. The points and meridians of Bloodletting on Bells palsy were Chichang, Hyopko in Yangmyong-Kyong.

• Korean Journal of Acupuncture
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• v.31 no.4
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• pp.208-217
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• 2014

Objectives and Methods : This study is to understand the properties and functions of twelve meridians. It aims to understand the meaning of the meridian names, and to study the properties of the six qi and the method of movement of the meridians by analyzing the six qi of the three yin and three yang from a meteorological perspective. The functions of twelve meridians based on the relationship between the operation of the internal organs and the meridians are then examined. Results and Conclusions : (1) The three yin and three yang includes the properties of six qi at the meridians. (2) The fundamental qi at reverting yin meridian lesser yin meridian and greater yin meridian has the properties of wind, heat and dampness, respectively, which are yang qi, while the fundamental qi at lesser yang meridian, yang brightness meridian and greater yang meridian has the properties of ministerial fire, dryness and cold, respectively, which are yin qi. (3) In the circulation of meridian qi, yang qi ascends at yin meridians while yin qi descends at yang meridians. (4) Three yin meridians belonging to the viscera help the function of intestines, which saves essence qi and then makes it go upward, while three yang meridians belonging to the bowels help the function of converting foodstuff and making it go downward. (5) In the human body, the internal organs play the primary role, and the meridians serve as helpers of the functioning of the internal organs by controlling the six qi.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.30.2-30.2
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• 2010

It is a mistaken impression that the midlatitude ionosphere was a very stable region with well-known morphology and physical mechanism. However, the large disturbances of midlatitude ionospheric contents in response to global thermospheric changes during geomagnetic storms are reported in recent studies using global GPS TEC map and space-born thermospheric UV images, and its importance get higher with the increasing application areas of space navigation systems and radio communication which are mostly used in the midlatitudes. Positive and negative storm phases are used to describe increase and decrease of ionospheric electron density. Negative storms result generally from the enhanced loss rate of electron density according to the neutral composition changes which are initiated by Joule heating in high-latitudes during geomagnetic storms. In contrast, positive ionospheric storms have not been well understood because of rare measurements to explain the mechanisms. The large enhancements of ground-based GPS TEC in Korea were observed on 8 and 10 November 2004. The positive ionospheric storm was continued except for dawn on 8 November, and its maximum value is ~65 TECU of ~3 times compared with the monthly mean TEC values. The other positive phase on 10 November begin to occur in day sector and lasted for more than 6 hours. The O/N2 ratios from GUVI/TIMED satellite show ~1.2 in northern hemisphere and ~0.3 in southern hemisphere of the northeast Asian sector on 8 and 10 November. We suggest the asymmetric features of O/N2 ratios in the Northeast Asian sector may play an important role in the measured GPS TEC enhancements in Korea because global thermospheric wind circulation can globally change the chemical composition during geomagnetic storms.

• Journal of Korean Society of Rural Planning
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• v.23 no.4
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• pp.153-168
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• 2017

The main objective of this study was to assess reference evapotranspiration based on multiple GCMs (General Circulation Models) and estimation methods. In this study, 10 GCMs based on the RCP (Representative Concentration Pathway) 4.5 scenario were used to estimate reference evapotranspiration. 54 ASOS (Automated Synoptic Observing System) data were constructed by statistical downscaling techniques. The meteorological variables of precipitation, maximum temperature and minimum temperature, relative humidity, wind speed, and solar radiation were produced using GCMs. For the past and future periods, we estimated reference evapotranspiration by GCMs and analyzed the statistical characteristics and analyzed its uncertainty. Five methods (BC: Blaney-Criddle, HS: Hargreaves-Samani, MK: Makkink, MS: Matt-Shuttleworth, and PM: Penman-Monteith) were selected to analyze the uncertainty by reference evapotranspiration estimation methods. We compared the uncertainty of reference evapotranspiration method by the variable expansion and analyzed which variables greatly influence reference evapotranspiration estimation. The posterior probabilities of five methods were estimated as BC: 0.1792, HS: 0.1775, MK: 0.2361, MS: 0.2054, and PM: 0.2018. The posterior probability indicated how well reference evapotranspiration estimated with 10 GCMs for five methods reflected the estimated reference evapotranspiration using the observed data. Through this study, we analyzed the overall characteristics of reference evapotranspiration according to GCMs and reference evapotranspiration estimation methods The results of this study might be used as a basic data for preparing the standard method of reference evapotranspiration to derive the water management method under climate change.

• Atmosphere
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• v.28 no.4
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• pp.457-467
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• 2018

This study investigated the variability of spring (March-May) forest fire risk in Korea for the period 1991~2017 and analyzed its relationship with large-scale climate factors. The Forest Weather Index (FWI) representing the meteorological risk for forest fire occurrences calculated based on observational data and its relationship with large-scale climate factors were analyzed. We performed the empirical orthogonal function (EOF) analysis on the spring FWI. The leading EOF mode of FWI accounting for about 70% of total variability was found to be highly correlated with total number of forest fire occurrences in Korea. The high FWI, forest fire occurrence risk, in Korea, is associated with warmer atmosphere temperature in midwest Eurasia-China-Korea peninsula, cyclonic circulation anomaly in northeastern China-Korea peninsula-northwest pacific, westerly wind anomaly in central China-Korea peninsula, and low humidity in Korea. These are further related with warmer sea surface temperature and enhanced outgoing longwave radiation over Western Pacific, which represents a typical condition for a La $Ni\tilde{n}a$ episode. This suggests that large-scale climate factors over East Asia and ENSO could have a significant influence on the occurrence of spring forest fires in Korea.

• Ocean and Polar Research
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• v.44 no.3
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• pp.191-207
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• 2022

Using the results of CTD casts made in Spring from 2017 to 2021, in this study we investigated the water mass distribution and occurrence of temperature inversion in the western seas of Jeju Island in spring. The distribution of water masses was characterized by cold and fresh water in the northwest and warm and saline water in the southeast, forming a strong thermohaline front running in the southwest-to-northeast direction. Strong temperature inversion mainly occurred in the frontal boundary when the cold water intrudes beneath the warm water at depths of 30-50 m. Analysis of the mixing ratio demonstrated that Jeju Warm Water is dominantly distributed in the western seas of Jeju Island, but its ratio can be modified depending on the southward extension of Yellow Sea Cold Water (YSCW). Results of in situ measurement showed that in 2020, the YSCW largely expanded to the western seas of Jeju Island, occupying approximately 40 % of the mixing ratio. Due to the expansion of YSCW, a strong thermohaline front was formed in the study area, thereby causing thick and strong temperature inversion. On the other hand, in 2018 the mixing ratio of YSCW was minimum (~18%) during the study period of 2017-2021, and thus a relatively weak frontal boundary was formed, without the occurrence of temperature inversion. The observational results also suggest that the interannual changes of water mass distribution and the associated temperature inversion in the western seas of Jeju Island are closely related with wind-driven Yellow Sea circulation in spring, which is the summer monsoon transition period.

• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.18-22
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• 2022

Photovoltaics (PV) power generation efficiency is affected by meteorological factors such as temperature and wind speed. In general, it is known that the power generation amount decreases because photovoltaics panel temperature rises and the power generation efficiency decreases in summer. Photovoltaics Thermal (PVT) power generation has the ad-vantage of being able to produce heat together with power, as well as preventing the reduction in power generation efficien-cy and output due to the temperature rise of the panel. In this study, the amount of heat collected by season and time was calculated for photovoltaics thermal modules using the International Weather for Energy Calculations (IWEC) data provided by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). Based on this, we propose a method of predicting the temperature of the photovoltaics panel using thermal analysis and then calculating the flow rate of coolant to improve power generation efficiency. As the results, the photovoltaics efficiencies versus time on January, April, July, and October in Jeju of the Republic of Korea were calculated to the range of 15.06% to 17.83%, and the maxi-mum cooling load and flow rate for the photovoltaics thermal module were calculated to 121.16 W and 45 cc/min, respec-tively. Though this study, it could be concluded that the photovoltaics thermal system can be composed of up to 53 modules with targeting the Jeju, since the maximum capacity of the coolant circulation pump of the photovoltaics thermal system applied in this study is 2,400 cc/min.