• Title/Summary/Keyword: Weir

Search Result 649, Processing Time 0.032 seconds

Park-Weir Excision for Flaring Alar Correction (넓어진 콧방울의 교정을 위한 Park-Weir 절제술)

  • Han, Sung-Bum;Park, Beyoung-Yun
    • Archives of Plastic Surgery
    • /
    • v.38 no.5
    • /
    • pp.674-678
    • /
    • 2011
  • Purpose: Straight closure line of classic Weir excision leaves visible scars and makes it difficult to precisely approximate resection margins. Hence this study introduces Park-Weir excision that effectively reduces alar width with minimal alar rim scar by 3-dimensional zigzag incision and properly controls the approximation of edges. Methods: From 2008 to 2010, 14 patients underwent Park-Weir excision, crossed wedge excision on alar rim not exceeding 5 mm in width. Each patient was photographed in the same position. Alar width and columellar height against intercanthal distance was compared preoperatively and postoperatively, using image analysis software. Results: Five patients were female and nine were male. Average follow up period was 8 month. Alar width was reduced by 50.50% to 45.96%, original alar width reduced by 8.98% without significant changes in columellar height which was reduced by 0.39%. No visible scar was reported during outpatient follow-up. Conclusion: Park-Weir excision effectively reduces alar width and corrects the flaring of alar without affecting the columellar height. Zigzag incision of Park-Weir excision leaves aesthetically more pleasant scar than straight single incision of classical Weir excision.

A Study on Hydraulic Characteristics for Labyrinth Weir of Triangle Single Type (삼각형 단일 Labyrinth 위어의 수리특성 연구)

  • Im, Jang-Hyuk;Park, Young-Jin;Baek, Kyung-Won;Song, Jai-Woo
    • 한국방재학회:학술대회논문집
    • /
    • 2008.02a
    • /
    • pp.191-194
    • /
    • 2008
  • Labyrinth weir is a hydraulic structure that can maintain constant water depth and increase overflow rate by increasing overflow width of weir through complicated displacement of its cross section. The labyrinth weir can be widely applied to various hydraulic facilities such as dam spillway, irrigation facilities, and canal structures. To date, however, few labyrinth weirs were applied to hydraulic facilities in Korea. Hence, in-depth research on labyrinth weir is highly required to efficiently apply the labyrinth weir to hydraulic facilities. This study was performed to analyze the hydraulic characteristics according to triangle labyrinth weir using hydraulic model experiments. The hydraulic characteristics provided in this study, which make it feasible to increase the overflow rate, and are expected to be widely applied to design of hydraulic facilities such as dam spillway and irrigation system.

  • PDF

A Study on the Efficiency Improvement of Existing Pool-and-Weir Type Fishway in Namgang Weir (남강수중보의 기존 전면월류형 계단식 어도의 효율성 개선에 관한 연구)

  • Lee, Hyeong-Rae;Kim, Ki Heung;Park, Ho Chul
    • Journal of the Korean Society of Environmental Restoration Technology
    • /
    • v.17 no.2
    • /
    • pp.61-71
    • /
    • 2014
  • A river fishway is a hydraulic structure enabling fish to overcome stream obstructions such as dams and weirs. The main aim of this paper is to investigate the collectibility of upstream-migrating fishes and hydraulic problems in pool-and-weir type fishway which has been established for upstream-migration at Namgang weir in the downstream of Namgang dam, and to grope for improvement measures which pool-and-weir type fishway can be switched to pool-and-partial weir type fishway through hydraulic field experiment. Exsisting fishway had problems which upstream-migrating fishes can not take a rest due to the seiche and vortex phenomena in pools and migrate to upstream because of height difference in entrance pool. In order to prevent hydraulically the seiche and vortex phenomena and establish rest area for fishes in each pool, we carried out hydraulic field experiments. In the fishway, it was to improve pool-and-weir into pool-and-partil weir, to decrease the height difference in entrance pool, and to reduce oriffice velocity of each pool. Also, we investigated fishes collectibility of after improving fishway for 6 days in September 2013. To resolve chronic problems(seiche-vortex phenomena and rest area for fishes), as weirs were remodeled into partial weir only which central part of weirs was part of non-overflow weir, we confirmed results that pool-and-weir type fishway could be switched to efficient pool-and-partial weir type fishway with relatively simple construction and low cost. Type-B which has the closed oriffices and the parts of non-overflow has the ideal conditions, but this conditions are limited to fishway of Namgang weir used in this study. Representative Ice-habor type fishway is pool-and-partial weir type fishway which has together parts of overflow and oriffices, and has excellent ability of upstream-migration. To switch from pool-and-weir type fishway to pool-and-partial weir type fishway, the size of oriffice has to be regulated by the discharge of fishway and the dimension on parts of non-overflow and overflow in weirs. Entrance pool is important facility which upstream-migrating fishes have to not only be collect but also charge with energy. In this study, entrance-pool is temporary and roughly-built, but fishes gather together more than the case of no entrance-pool. In the case of fishway which was protruded to downstream, as entrance of fishway turns toward or parallels to weir, the collectibility of fishway was excellent by attraction water.

Seasonal Variation of Water Temperature Before and After Weir Construction Using Satellite Image in the Nakdong River (낙동강유역에서 위성영상을 이용한 보 건설 전후 수온의 계절변화)

  • Kim, Sang-Woo;Kim, Hae-Dong;Lim, Jin-Wook;Ahn, Ji-Suk
    • Journal of Environmental Science International
    • /
    • v.24 no.11
    • /
    • pp.1417-1430
    • /
    • 2015
  • In this study we were to explore the seasonal variation of water temperature distributions before and after weir construction at Gumi, Chilgok, Gangjung(Goryung), Dalsung in the Nakdong River using Landsat satellite images. Relationship between in-situ water temperature and radiance values of Landsat-5, 7, 8 satellite images showed high correlation. Seasonal variation of water temperature in Nakdong River showed that the fluctuation ranges of water temperature before weir construction were larger than those after weir construction. This indicated that the variation of water temperature is due to the difference of heat storage volume by weir construction and dredging work. In particular, the water temperature after weirs construction in autumn was 4-8 times lower than that before weirs construction. Water temperature after weir construction decreased in spring and summer at the downstream of Gumi weir and Gangjung(Goryung) weir, and the upstream of Dalsung weir. In autumn and winter, the water temperature after weir construction increased in the upstream and downstream of the whole weirs except upstream of Gumi weir. Relationship between water temperature and meteorological elements (air temperature, wind speed, sunshine, radiation) showed high correlation of above 94% in air temperature, and then radiation was high correlation before and after 65%.

Analyzing the Effect of a Weir Construction on the Groundwater Flow System (보 건설이 주변지역 지하수 흐름계에 미치는 영향)

  • Jeong, Soo-Jeong;Koo, Min-Ho
    • Journal of Soil and Groundwater Environment
    • /
    • v.17 no.3
    • /
    • pp.39-48
    • /
    • 2012
  • Visual MODFLOW, a three dimensional groundwater flow model, was used to analyze effects of a weir construction in an alluvial stream on the nearby groundwater flow system. A hypothetical conceptual model was developed to investigate how the groundwater level and the water budget could change after a weir construction depending on the location of tributary streams. A site example, dealing with the Juksan weir installed in the Yeongsan River, was also demonstrated to predict the effects of the weir construction. Model results show that impacts of a weir construction on the groundwater flow system greatly vary depending on how far a tributary is located and whether it is located downstream or upstream from the weir. Therefore, consideration of the location of tributaries in planning the location of a weir could effectively minimize the impacts of a weir construction on the groundwater flow system. It is also demonstrated that model results are highly dependent upon how the model is dealing with small tributaries and agricultural drainage channels, which can be easily found nearby the main streams, acting as major water bodies for groundwater discharge. The model for the Juksan area shows that the weir construction will change the direction of groundwater flow in some areas, leading to changes of groundwater quality and interaction of the Yeongsan River to the aquifer from a gaining to a losing stream. The model also predicted the areas where rise of groundwater level caused by the Juksan weir could adversely affect plant growth, and thereby suggested installing new drainage channels as a countermeasure to drawdown the groundwater level.

Analysis of Hydraulic Characteristics by Sediment Protection Weir on Natural River Estuary (자연하도 하구부의 방사보에 의한 수리학적특성 해석)

  • Ahn, Seung-Seop;Choi, Yun-Young
    • Journal of the Korean Society of Industry Convergence
    • /
    • v.4 no.1
    • /
    • pp.51-60
    • /
    • 2001
  • This study examines the effects of removal of the sediment protection weir at Taehwa river mouth on hydraulic and around river environment considering the fact that the effects of the sediment protection weir which is installed to protect water level drop of Ulsan harbor caused by sediments according to flood in Taehwa river, Dong-chun, and so forth may add water quality contamination by flow stagnance in normal and drought period and accumulation of pollutants. The result is as follows. First, it is estimated from the examination of variation characteristics water depth and level for Taehwa river before and after removal of the sediment protection weir that about 0.01m of water depth down according to removal of the sediment protection weir occurs when low flow runs between the sediment protection weir which is located about 2.3km away from the estuary and Samho-gyo which is about 9.0km away from the sediment protection weir, and about 0.01~0.56m(directly upstream point of the sediment protection weir 0.56m, Myongchon-gyo 0.14m, Ulsan-gyo 0.03m, and Taehwa-gyo 0.02m) downs when design flood flows between the sediment protection weir and the upstream of Taehwa-gyo which is 10km away from the sediment protection weir. Therefore, it is thought that variation of hydraulic characteristics of water depth down and so on according to removal of the sediment protection weir is slight because water depth variation is only about 1cm between directly upstream point of the sediment protection weir and Samho-gyo. Next, it is estimated from the examination of variation characteristics of flow velocity for Taehwa river before and after removal of the sediment protection weir that about 0.0lm/s of flow velocity increase occurs between the directly upstream point of the sediment protection weir which is about 2.4km away from the estuary and the directly upstream point of Samho-gyo when low flow runs, and about 0.01~0.44m/s increases between the sediment protection weir and Samho-gyo when design flood flows. Therefore, riverbed erosion by the increased flow velocity is concerned but it is thought that the concern about riverbed erosion is not great because the mean velocity is about 0.07~1.36m/s when low flow runs, and about 1.02~2.41m/s when design flood flows for the sector which experiences the flow velocity variation.

  • PDF

Hydraulic Characteristics and Upstream Migration of Fish by the Weir Type in a Pool-Weir Fishway (階段式魚道에서 隔壁 形狀에 따른 水理學的 特性 및 魚類의 上流移動)

  • 김진홍
    • Water for future
    • /
    • v.29 no.6
    • /
    • pp.225-235
    • /
    • 1996
  • This study deals with hydraulic characteristics and their effects on upstream migration of fish by the weir type in a pool-weir fishway, and presents an optimal type of weir for an easy upstream migration. Experiment was performed to estimate hydraulic conditions by the weir type and to determine which type was good. The results showed that a rectangular weir with a small rectangular notch installed by a zig-zag type was preferable to a simple weir with no notch or to a trapezoidal weir, since it makes possible for upstream migration even when a water level draws down and moreover, it makes falling flow through a notch which facilitates upstream migration. It was proposed that the notch must be designed that the flow situation may keep the streaming flow so long as the maximum flow velocity does not exceed the critical swiming velocity, i.e., the dimensionless flow rate may exist whthin the range of 0.27 and 0.41.

  • PDF

Experimental Analysis of Flow Characteristics and Bed Changes Over Oblique Weirs (위어 설치각도에 따른 흐름특성 및 하도 변화의 실험적 분석)

  • Jang, Chang-Lae;Kim, Gi Jung
    • Ecology and Resilient Infrastructure
    • /
    • v.4 no.4
    • /
    • pp.245-254
    • /
    • 2017
  • In this study, the flow characteristics and bed changes in the upstream and downstream of weirs with the variation of the weir angels are investigated quantitatively through the laboratory experiments. As the angle of weir increases, the effective weir length decreases. Delta is developed by the sediments inflow upstream and migrates downstream. Delta migration speed decreases as it approaches to the weir upstream, and the size is getting big. As the dimensionless weir length increases, the dimensionless wave length decreases at the downstream of the weir. However, the dimensionless bar height decreases. The dimensionless wavelength increases with the bar height downstream from the weir.

Numerical Analysis of the Outlet Structure Effect on the Flow and Settling Performance of the Rectangular Clarifiers (장방형 2차 침전지 유출부의 구조가 유동 및 성능에 미치는 영향에 대한 수치 해석적 연구)

  • Kim, Youngchul;Park, Moo Jong;Sheen, Dong-Jin
    • Journal of Korean Society on Water Environment
    • /
    • v.22 no.3
    • /
    • pp.557-565
    • /
    • 2006
  • Proper operation of clarifier partly depends on outlet conditions. Effluent has to be uniformly withdrawn to prevent scouring of settled sludge and carry over of settling sludge from the clarifier. In this paper, 3-D numerical model was employed to analyze the flow and settling performance of the rectangular clarifier. There were two simulation conditions of which in the same clarifier, the first one was assumed to have a 11.5 meter weir length and the second has 8.5 meters. Shape, location and placement of the weir structure were different, but both of those outlets meet weir loading design criteria. Simulation results indicate that clarifier with longer weir generally gave strong and unstable currents at the mid-stream where the weir starts while in the clarifier with short and relatively simple weir, uniform and stable flow was observed in most parts of the settling zone, and especially at the weir region. These flow conditions affected settling performance. Effulent SS concentration from clarifier equipped with the long and complicated placement of weir was 24.5 mg/L, but 7.0 mg/L from the clarfieir having short weir length. From this study, it can be concluded that as reported from other studies, weir loading does not guarantee settling performance and 3-D numerical model can be a useful tool for determining and validating outlet structure.

Numerical Analysis of the Sediment Pass-Through from the Sangju Weir and the Gumi Weir by using CCHE2D (CCHE2D모형을 이용한 보 상류에 퇴적된 토사의 배출 효과 분석 - 상주보와 구미보를 중심으로 -)

  • Lee, Kyung Su;Jang, Chang-Lae;Son, Kwang Ik;Hwang, Man Ha
    • Journal of Korean Society on Water Environment
    • /
    • v.29 no.6
    • /
    • pp.813-824
    • /
    • 2013
  • In this study, sediment pass-through (SPT) from the Sangju Weir and Gumi Weir in the Nakdong River is analyzed numerically using CCHE2D. Sediment delivery is analyzed to predict the sediment discharge rate in the Sangju Weir and Gumi Weir. The sediment discharge from the Sanju Weir is 4,381 tons in the inflow of $3,857m^3/s$, which are 2 year frequency discharge, for 48 hours, and the sediment discharge is 2,766 tons in the inflow of $1,500m^3/s$. The maximum sediment delivery occurs in the immediate downstream of the weir. The sediment discharge from the Gumi Weir is 3,216 tons in the inflow of $5,400m^3/s$, which are 2 year frequency discharge, for 48 hours, and the sediment discharge is 73 tons in the inflow of $3,857m^3/s$. The maximum sediment delivery occurs in the weir. Therefore, the effectiveness of sediment delivery is high in the condition of the 2 year frequency discharge and the gate in the weirs fully are opened.