Bank erosion and accretion dynamics explored by GIS techniques in lower Ramganga river, Western Uttar Pradesh, India

Rameswar Mukherjee,Ram Bilas,Sumantra Sarathi Biswas,Raghunath Pal 대한공간정보학회 2017 Spatial Information Research Vol.25 No.1

The rivers of Indo-Ganga–Brahmaputra (IGB) plain are widely known for their dynamicity and hazard proneness. All of the large rivers that originated from Himalaya and flowing into the IGB plain (like Ganga, Ghagra, Ramganga, Rapti, Bagmati, Koshi, Teesta, Brahmaputra, etc.), shift their position vigorously and create massive kind of bank erosion. In the present study, we have selected 35.30 km alluvial reach of lower Ramganga river which is one of the major tributaries of the Ganga River. The study aims to quantify the amount and rate of bank erosion and accretion phenomena, also to find out the nature of bank erosion and accretion. In the present paper, we assessed the bank erosion and accretion of 91 years. We have taken 1923 toposheets, and Landsat images of 1972, 1981, 1993, 2003, and 2014 for the study. Demarcation of bank lines and estimation of bank erosion and accretion areas (for left and right bank separately) were done by using ArcGIS. Detailed field works were also done for investigating the nature of bank erosion and accretion as well as for bank line demarcation. The study reveals that in all of the evaluated periods, the river has experienced differential rates and amounts of bank erosion and accretion. The widening of channel, extension of meander bends along with lateral movements of the channel and chute cutoff are mainly responsible for bank erosion and accretion, while liquefaction and flowage of bank materials and shear failure were the principle mechanisms for that.

Multi-physics CFD simulation of ice accretion and shedding on fan rotor

Makoto Yamamoto 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.11

Ice accretion is a phenomenon where super-cooled water droplets impinge and accrete on a body. When ice layer is formed on an aircraft wing and fuselage, it affects on the performance by increasing drag and decreasing lift, and it can cause a serious accident. On a jet engine, ice accretion disturbs the inlet flow and separated ice pieces can damage to the compressor and casing. Actually, there have been a lot of instances of accidents due to ice accretion. The estimation of ice formation is essential to avoid such accidents, and it can be useful to reduce the cost and design period in the development of an aircraft and a jet engine. The fan rotor blade of a jet engine is one of aircraft components where severe ice accretion occurs. However, few experimental and computational researches on rotor blade icing have been carried out. In the present study, we focus on ice accretion of a fan rotor blade. 3-dimensional multi-physics computational fluid dynamics (CFD) simulations are conducted, to investigate the icing formation and the ice shedding phenomena. Moreover, icing characteristics of linear and swept blades are numerically clarified.

ACCRETION-JET MODEL FOR THE HARD X-ray Γ - L_X CORRELATION IN BLACK HOLE X-ray BINARIES

YANG, QI-XIANG,XIE, FU-GUO,YUAN, FENG,ZDZIARSKI, ANDRZEJ A.,GIERLINSKI, MAREK,HO, LUIS C.,YU, ZHAOLONG The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2

In this work, we study the correlation between the photon index (${\Gamma}$) of the X-ray spectrum and the 2-10 keV X-ray luminosity ($L_X$) for black hole X-ray binaries (BHBs). The BHB sample is mainly from the quiescent, hard and intermediate states, with values of $L_X$ ranging from ${\sim}10^{30.5}$ to $10^{37.5}$ erg $s^{-1}$. We find that the photon index ${\Gamma}$ is positively or negatively correlated with the X-ray luminosity $L_X$, for $L_X$ above or below a critical value, ${\sim}10^{36.5}$ erg $s^{-1}$. This result is consistent with previous works. Moreover, when $L_X{\leq}{\sim}10^{33}$ erg $s^{-1}$, we found that the photon index is roughly independent of the X-ray luminosity. We interpret the above correlations in the framework of a coupled hot accretion flow - jet model. Besides, we also find that in the moderate-luminosity region, different sources may have different anti-correlation slopes, and we argue this diversity is caused by the different value of ${\delta}$, which describes the fraction of turbulent dissipation that directly heats electrons.

2차원 에어포일에서의 결빙부착 수치해석

신훈범(H.B. Shin),최원(W. Choi),서석주(S.J. Seo),유진복(J.B. Ryu) 한국전산유체공학회 2009 한국전산유체공학회 학술대회논문집 Vol.2009 No.4

Ice accretion is one of the potential hazards in airplane flight, adversely affecting aircraft aerodynamic. There are two distinct icing analysis that can be simulated. One is predicting the effect of ice on the aerodynamic performance of airfoils when ice geometry is known. The other is simulating ice accretion. This work presents the method of icing accretion analysis. This work presents an Eulerian approach to calculate the droplet collection efficiency on the 2D airfoil. The initial flow solution are obtained the FLUENT and copled with droplet motion in the ambient condition.

풍력 블레이드의 결빙에 의한 공력 영향성 전산 예측

박지호(J.H. Park),정기영(K.Y. Jung),명노신(R.S. Myong) 한국전산유체공학회 2013 한국전산유체공학회지 Vol.18 No.3

A significant change in aerodynamic characteristics of wind turbine blade can occur by ice formed on the surface of the blade operated in cold climate. The ice accretion can result in performance loss, overloading due to delayed stall, and excessive vibration associated with mass imbalance. In this study, the impact of ice accretion on the aerodynamic characteristics of NREL 5MW wind turbine blade sections is examined by a CFD-based method. It is shown that the thickness of ice accretion increases from the root to the tip and the effects of icing conditions such as relative wind velocity play a significant role in the shape of ice accretion. In addition, the computational results are used to assess the degradation in the lift and drag coefficients of the blade sections.

풍력 블레이드의 결빙에 의한 공력특성 및 성능 변화

박지호(Ji-Ho Park),명노신(Rho-Shin Myong) 한국항공우주학회 2014 韓國航空宇宙學會誌 Vol.42 No.2

추운 기후에서 운영되는 풍력터빈 시스템의 표면에 발생한 결빙으로 인하여 공기역학적 성능이 크게 저하될 수 있다. 이러한 결빙은 양력감소 및 항력증가를 야기하고, 발전효율에 부정적인 영향을 미치게 된다. 이로 인하여 풍력발전기의 성능저하 또는 과부하, 무게중심의 변화에 따른 과도진동, 결빙파편이 지상으로 떨어질 경우의 안전성 문제, 계기의 결빙으로 인한 계기 측정오차, 최악의 경우 풍력 시스템 정지 등의 문제가 발생한다. 본 연구에서는 결빙증식이 풍력 발전기의 공력특성에 미치는 영향을 CFD 기법을 이용해 분석하였다. 또한 결빙증식 결과를 바탕으로 BEM 기법을 적용시켜 삼차원 블레이드에 대한 공력성능을 계산하였다. 결빙의 두께는 상대적인 속도차이에 의해 블레이드 중심에서 끝단으로 갈수록 증가함을 알 수 있었고, 공기의 속도가 결빙증식에 미치는 주요 인자임을 확인하였다. A significant degradation in the aerodynamic performance of wind turbine system can occur by ice accretion on the surface of blades operated in cold climate. The ice accretion can result in performance loss, overloading due to delayed stall, excessive vibration associated with mass imbalance, ice shedding, instrumental measurement errors, and, in worst case, wind turbine system shutdown. In this study, the effects of ice accretions on the aerodynamic characteristics of wind turbine blade sections are investigated on the basis of modern CFD method. In addition, the computational results are used to predict the performance of three-dimensional wind turbine blade system through the blade element momentum method. It is shown that the thickness of ice accretion increases from the root to the tip and the effects of icing conditions such as relative wind velocity play significant role in the shape of ice accretion.

Assessment of bank erosion and channel shifting of Padma River in Bangladesh using RS and GIS techniques

Sultana Jahan Ophra,Sameena Begum,Raihanul Islam,Md. Nazrul Islam 대한공간정보학회 2018 Spatial Information Research Vol.26 No.6

Bangladesh is a riverine country. Every year it faces many natural hazards due to river. Bangladesh is mainly formed by alluvial deposits. It faces riverbank erosion frequently due to regular shifting of river channels. This research work provides an overview of the trend of riverbank erosion of Padma River of Munshiganj, Madaripur and Shariatpur district. It also shows the land cover change due to riverbank erosion. The riverbank erosion was calculated by using remote sensing and geographic information systems (GIS) techniques. Only secondary data have been used to reach the research goals. Various computer software such as Erdas Imagine, Arc GIS, Google Earth, Environment for Visualizing Images etc. have been used to process and analyze raw data. In this study, using seven selected images of Landsat TM and OLI acquired from 1988 to 2017, the riverbank migration patterns and land dynamics of Padma resulted from accretion/ erosion processes for 29 years were investigated. The migration rates are based on the differences in 1988–1993, 1993–1998, 1998–2003, 2003–2008, 2008–2013 and 2013–2017. The average erosion and accretion rates are 1472.056 and 1610.152 ha/year of Padma, respectively. This study shows Padma got meandered and braided from almost straight channel in the time span.

The Effects of Dietary Lysine Deficiency on Muscle Protein Turnover in Postweanling Pigs

Chang, Yi-Ming,Wei, Hen-Wei Asian Australasian Association of Animal Productio 2005 Animal Bioscience Vol.18 No.9

The main purpose of this study is to investigate the effects of dietary lysine deficiency on protein turnover of porcine muscles. There were 18 LYD three-breed-crossing postweanling barrows from six litters cannulated with gastric tubes through the esophagus at approximate 10 kg of body weight and allocated into three treatment groups. When their body weights reached over 12 kg, one group was sacrificed for determining the initial protein masses of m. masseter, m. longissimus dorsi, m. adductor and m. biceps femoris from the right body side. The others received a diet containing 100% or 61.4% (calculated values) of the lysine requirement (NRC, 1998) multiplied by 1.103 for a period of 17 days. Daily feed provision was computed for each pig according to body weight at the same day. All pigs were infused a flooding dose of $^2$H$_5$-phenylalanine to determine the fractional protein synthesis rates (FSR) of the aforementioned muscles in the end. Their four muscles from the right body side were also dissected for measuring the fractional rates of protein accretion (FAR). As for protein degradation, fractional rates (FDR) were calculated by differences between synthesis and accretion. Results showed that the lysine deficiency resulted in, significantly (p<0.05), lighter body weights, smaller muscles and a slower growth rate. The protein mass, accreted by the muscles, of the deficient group was only 54% averaged of the pigs fed adequately (p<0.05). The FAR of these muscles in the deficient group was significantly lower (p<0.05) and only achieved 61.1% averaged of the control; there was no significant difference (p>0.05), nevertheless, in the amino-acid composition of muscles between two groups. The lysine deficiency reduced significantly (p<0.05) the FSR of m. longissimus dorsi but did not influence its FDR. The m. biceps femoris also presented an inhibited FSR while its FDR reduced only exhibited a very high tendency (p = 0.055) compared to the adequately-fed pigs. As for the m. masseter and m. adductor, both of the FSR and FDR were depressed significantly (p<0.05) by the lysine deficiency, and changes in the FSR were severer than those in the FDR, so that their FAR were significantly slower (p<0.05) in comparison with the control group. The lysine deficiency also inhibited the RNA translation activity of the muscles while the effects on RNA capacity were not significant (p>0.05). In conclusion, the FAR of muscle protein was changed by the current lysine deficiency through the alterations in the FSR and/or FDR.

대변위 풍진동 실험장치를 이용한 송전선 풍동실험

김재민,석철근,이승우 한국풍공학회 2016 한국풍공학회지 Vol.20 No.2

This study was conducted as an effort to find the method to carry out a complete investigation of the gallopingphenomenon of transmission lines under ice and snow accretion. With this study a method and test device that enables simulationof the galloping motion of actual transmission lines in a wind tunnel have been developed. The test apparatus proposed herecomposed of a transmission line section model supported in the wire axis direction by eight elastic cords. This equipment allowsthe section model to vibrate with large amplitudes at low frequencies in the vertical, horizontal, and torsional directions. The windtunnel test results has validated that the test apparatus would be able to confirm the phenomenon of the actual transmission lineGalloping. 착빙 및 착설에 의한 송전선의 갤로핑 발생 메커니즘의 규명을 위해 본 연구에서는 실제규모의 송전선 풍진동 모사를 가능하게 하는 실험방법과 실험장치를 개발하였다. 개발된 실험장치는 8줄의 탄성와이어로 지지되는 송전선단면 모형으로 구성되며, 수직, 수평 및 비틀림 방향으로 저 주파수에서 큰 변위의 진폭으로 진동이 가능하다. 풍동실험을 통하여 본 실험방법의 유효성을 확인 하였고 실제 송전선의 갤로핑현상의 재현이 가능하다는 것을 알 수 있었다.

철재형 이안제의 설계외력 산정기법 검증을 위한 실해역 시험

권혁민,권오균,한유식,윤강훈,Kweon. Hyuck Min,Kwon. Oh Kyun,Han. Yu Sik,Yoon. Kang Hun 한국방재학회 2012 한국방재학회논문집 Vol.12 No.1

철재형 이안제는 구조형식이 단조롭고 설계가 용이하며 퇴적파랑을 통과시키는 등 장점이 많아 기존의 중력식 방파제의 대안으로서 기대된다. 철재형 이안제의 설계기법은 권혁민 등(2011), 권오균 등(2011), 이정렬 등(2011)이 보고한 바 있다. 권혁민 등(2011)은 철재형 이안제의 설계외력을 산정함에 있어서 유의파고에 상당하는 규칙파를 사용하고 말뚝의 심도설계를 위한 연직상향력은 수평판의 지점별 최대압력분포로부터 산정할 것을 제안하였다. 본 연구는 제안된 외력산정기법의 실해역 검증을 위하여 수행되었다. 또한 본 연구에서는 설계상 가능한 구조물에 대하여 실해역 실험을 통하여 축조 과정 기술 확보, 파괴 여부 판정, 철거 가능성을 검증하고자 한다. 철재형 이안제에 사용된 소파판은 <TEX>$9m{\times}12m$</TEX>(길이<TEX>${\times}$</TEX>폭)의 크기이고, 강관말뚝은 직경 711 mm, 두께 12 mm, 길이 23.2 m이다. 실해역 실험 결과, 본 구조물의 축조는 기존의 장비로 약 8시간 만에 1셀의 시공이 가능하고, 유의파고 5.83 m의 외력에 대하여 말뚝의 수평 및 수직 상호변위는 매우 작게 발생하였으며, 철거는 양호한 기후조건에서 2일이 소요되었다. 본 실해역 시험을 통하여 권혁민 등(2011)의 철재형 이안제에 작용하는 외력산정기법이 유용하며 말뚝의 인발력에 대한 마찰 안전율이 약 2.0에 상당하다는 것을 알았다. 또한 철재형 이안제는 설계, 시공, 철거가 간단하며, 소파판의 착탈식 운영방식으로 해안의 사정에 따라 모래포집량 조절이 가능할 수 있다는 기대를 높이게 되었다. The steel-type breakwater has the merits of structural simplicity and passing the long period wave for beach accretion. So, it has been expected to be a key tool for the strategic beach protection technology. The design methodology of the steel-type breakwater was published by Kweon et al.(2011), Kwon et al.(2011), Lee et al.(2011). For the analysis of the resistant friction load acting on the pile, Kweon et al. proposed the estimation method of the design up lift force acting on the dual horizontal plate. With a train of regular wave corresponding to the significant one, they integrated the distribution of the biggest pressure at each point. For the verification of the estimation method of the load on the pile, the study is carried out the experiment in a real sea state. Moreover, the construction procedure, the displacement, joint checking and removal possibility of the steel-type breakwater are discussed. The constructed breakwater has the horizontal wave energy dissipator of <TEX>$9m{\times}12m$</TEX>(<TEX>$length{\times}width$</TEX>) and pile diameter of 711 mm, thickness of 12 mm, length of 23.2 m. The construction took about 8 hours for 1 cell composed of 9 piles and 1 horizontal dual plate. There is a little vertical and horizontal displacement of pile attacked by the maximum wave height of 5.83 m. The removal of 1 cell took about 2 days. This study shows the merits of the easier design, faster construction and simpler removal of the steel-type breakwater. The structure could be estimated as a stable one because it has the horizontal dissipator on which acting a little compression and a little uplift force due to the perforated holes. Moreover, the easier removal could make it possible to manage the coastal line as depending on the conditions of erosion or accretion sand volume.