Numerical Simulation of Wave Characteristics around Coastal Structures by OLAFOAM

본 연구는 OpenFOAMⓇ을 기반으로한 OLAFOAM을 적용하여 해안구조물의 모델링과 그의 적용을 다루며, 구조물로는 투과성 구조물을 대표하는 잠제와 격자블록으로 결속된 방파제인 원형유공방파제를 대상으로 하였다. 따라서 본문에서는 크게 2가지 주제를 다루며, 첫 번째 주제는 잠제를 대상으로 (1) 파와 흐름의 공존장내 2차원투과성잠제 주변에서의 파랑특성의 수치해석, (2) 3차원투과성잠제 주변에서 수면변동과 내부유속변동의 특성에 관한 수치해석 그리고 (3) 파와 흐름의 공존장내 3차원투과성잠제 주변에서 수면변동과 내부유속변동의 특성에 관한 수치해석과 같이 3개의 부분으로 구성 하였으며, 두 번째 주제는 3차원불규칙파동장하에서 원형유공케이슨 방파제를 대상으로 월파량, 반사율, 파압분포 및 그들의 상호연관성에 대한 수치시뮬레이션이다. 첫 번째 주제의 (1)에서는 먼저 1) 단파하 투과성구조물에서 파의 변형, 2) 규칙파하 잠제에 의한 파의 변형과 모래지반내 과잉간극수압변동 및 3) 흐름하 규칙파의 변형과 연직유속분포에 대해 기존의 각 실험결과와 비교⋅검토하고, 불규칙파를 조파하여 목표한 파의 재현과 주파수스펙트럼을 비교⋅검토하여 OLAFOAM의 타당성을 검증한다. 이로부터 지금까지 거의 검토되지 않은 규칙파와 흐름의 공존장 및 불규칙파와 흐름의 공존장에 설치된 2차원투과성잠제에 대해 배후사면을 모래 혹은 자갈로 고려한 경우 흐름방향 등에 변화에 따른 잠제 주변에서 파고 및 , 주파수스펙트럼, 쇄파, 평균유속 및 난류운동에너지 등의 변동특성을 면밀히 검토하였다. (2)에서는 OLAFOAM의 3차원수치해석의 타당성을 검증하기 위해 1) 3차원투과성직립벽에 의한 파의 변형과 파압변동 및 2) 규칙파동장하에서 3차원불투과잠제에 의한 파의 변형 및 흐름에 대한 기존의 실험결과와의 비교⋅검토를 하였다. 이로부터 규칙파, 불규칙파 및 설상사주 형성조건하에 투과성잠제 주변에서 형성되는 파고 및 분포와 같은 수면변동의 특성과 배후에서 형성되는 설상사주의 주요외력으로 평균유속, 연안류 및 난류운동에너지 등을 포함한 유속장의 특성을 수치적으로 검토하였다. 또한, 연안류에 의한 수송유량으로부터 해안선의 지형변동도 예측하였다. (3)에서는 (1)과 (2)를 확장하여, 파와 흐름의 공존장 및 설상사주의 형성조건하에 설치된 3차원투과성잠제에 관해 흐름방향에 따라 변화되는 잠제 주변에서 파고 및 분포와 같은 수면변동의 특성 및 설상사주의 주요외력으로 작용하는 평균유속, 연안류 및 난류운동에너지 등을 포함한 유속장의 특성을 수치적으로 검토하였으며, 대상파랑은 규칙파와 불규칙파로 하였다. 또한, 연안류에 의한 수송유량으로부터 해안선의 지형변동도 예측하여, 흐름방향에 따른 설상사주의 형성과정에 미치는 영향을 검토하였다. 두 번째 주제에서는 먼저 규칙파랑하 3차원슬리트케이슨방파제에서 파의 파압변동에 대해 기존의 실험결과와 비교⋅검토하여 OLAFOAM의 원형유공케이슨 방파제와 같은 특수방파제에 대한 수치해석의 타당성을 검증하였다. 이로부터 슬리트케이슨제와 유사한 원형유공케이슨 방파제가 설치된 일정수심의 3차원수치파동수조에 불규칙파를 조파하여 유수실 폭과 유의파고 및 유의주기의 변화에 따른 원형유공케이슨 방파제에서 월파량, 반사율, 파압분포 및 그들의 상호연관성을 면밀히 검토⋅분석하였다. 또한, 파압분포는 불투과연직벽체에 대한 Goda 식 및 슬리트케이슨제에 대한 Takahashi 식과 비교하였으며, 반사율은 Tanimoto 식과 비교하였다. |This study deals with the modeling and application of the coastal structures using OLAFOAM based on OpenFOAMⓇ, and the structures were submerged breakwater representing permeable structure and circular perforated caisson breakwater consisting of a bundle of latticed blocks. This paper consists of the two topics. The first topic includes 3 parts: (1) numerical analysis on wave characteristics around 2-dimensional permeable submerged breakwater in wave and current coexisting field, (2) numerical analysis on variation characteristics of water surface and velocity around 3-dimensional permeable submerged breakwater, and (3) numerical analysis on variation characteristics of water surface and velocity around 3-dimensional permeable submerged breakwater in wave and current coexisting field. The second topic is numerical simulation on wave overtopping, reflection, wave pressure acting on circular perforated caisson breakwaters and the interconnectivity between them in a 3-dimensional numerical irregular wave tank. In the first part of the first topic, OLAFOAM was validated for 1) wave transformation inside porous structure under bore conditions, 2) wave transformation and fluctuation of excess pore-water pressure in sand bed by submerged breakwater under regular wave condition, and 3) regular wave transformation and resultant vertical velocity distribution under current by comparison with existing laboratory measurements and the performance for irregular waves was examined from the reproducibility of the target irregular waves and frequency spectrum analysis. Hereafter, this part, which is almost no examination carried out until now, analyzed closely variation characteristics of wave height or , frequency spectrum, breaking waves, averaged velocity and turbulent kinetic energy around 2-dimensional porous submerged breakwater in the wave and current coexisting field for the case of sandy or graveled rear beach. In the second part of the first topic, the comparisons are made with available experimental results on 1) wave transformation and fluctuation of wave pressure by a 3-dimensional permeable upright wall and 2) wave transformation and fluctuation of wave velocities by a 3-dimensional impermeable submerged breakwater to verify its applicability to the 3-dimensional numerical analysis. Hereafter, the characteristics of the water surface variations like wave height or distribution and velocity fields including the average flow velocity, longshore current and turbulent kinetic energy acting as the main external forces formed around the 3-dimensional permeable submerged breakwaters are investigated under regular or irregular waves and salient formation. Shoreline response is also predicted by the longshore-induced flux. The third part of the first topic is expanded first and second parts. This part, which is almost no examination carried out until now, analyzed closely the characteristics of the water surface variations like wave height or distribution and velocity fields including the average flow velocity, longshore current and turbulent kinetic energy acting as the main external forces formed around the 3-dimensional permeable submerged breakwaters are investigated under wave-current coexisting field and the formation condition of salient. The target waves were regular and irregular waves. Shoreline response is also predicted by the longshore-induced flux, and the effect on formation process of salient is investigated as existing current and current direction. In the second topic, to investigate the applicability of OLAFOAM to the specialized breakwater like the circular perforated caisson breakwater, the variations of wave pressure acting on the 3-dimensional slit caisson breakwater were compared to the previous experimental results under the regular wave conditions. As a result, a series of numerical simulations for the circular perforated caisson breakwaters, which is similar to slit caisson breakwater, was carried out under the irregular wave actions. The hydraulic characteristics of the breakwater such as wave overtopping, reflection, and wave pressure distribution were carefully investigated respect to the significant wave height and period, the wave chamber width, and the interconnectivity between them. Also, the wave pressure distribution was compared with the Goda equation for the impermeable vertical wall or Takahashi equation for the slit caisson breakwater, and the reflection coefficient was compared with the Tanimoto equation.ABSTRACT ·························································································································(i) 요약 ·································································································································(iii) 목차 ··································································································································(v) LIST OF FIGURES ·············································································································(viii) LIST OF TABLES ···············································································································(xii) LIST OF PHOTOS ··············································································································(xiii) 제1장 서론 1.1 연구의 배경 및 목적 ·······················································································(1) 1.2 연구의 구성 ·····································································································(9) References ···········································································································(10) 제2장 수치해석이론 2.1 지배방정식 ····································································································(17) 2.2 수치파동수조에 의한 불규칙파 조파 ·······························································(19) References ···········································································································(20) 제3장 파-흐름 공존장내 2차원잠제 주변의 파랑특성 3.1 수치해석의 검증 ··························································································(21) 3.1.1 다공성매질을 통과하는 단파의 수위변화에 대한 검증 ·····························(21) 3.1.2 잠제 주변의 파랑변동과 잠제 내 및 지반 내에서 과잉간극수압변동에 관한 검증 ···(22) 3.1.3 파랑과 흐름의 공존장에 있어서 수위변화와 평균유속변화에 대한 검증 ·····(25) 3.1.4 불규칙파의 조파검증 ·········································································(27) 3.2 계산조건 ········································································································(28) 3.3 규칙파-흐름 공존장내 잠제 주변의 파랑특성의 수치해석 ································(30) 3.3.1 수위변동과 주파수스펙트럼 ·······························································(30) 3.3.2 쇄파형상 ··························································································(34) 3.3.3 파고의 분포 ·····················································································(37) 3.3.4 평균유속 및 평균난류운동에너지의 분포 ···············································(38) 3.4 불규칙파-흐름 공존장내 잠제 주변의 파랑특성의 수치해석 ······························(41) 3.4.1 수위변동과 주파수스펙트럼 ·······························································(41) 3.4.2 쇄파형상 ··························································································(45) 3.4.3 의 분포 ·····················································································(48) 3.4.4 평균유속 및 평균난류운동에너지의 분포 ···············································(49) 3.5 결언 ···············································································································(52) References ···········································································································(53) 제4장 설상사주 형성조건 하에 있는 3차원투과성잠제 주변에서 수면변동 및 내부유속변동의 특성 4.1 수치해석의 검증 ·····························································································(54) 4.1.1 3차원투과성직립벽 주변에서 수위 및 파압에 대한 검증 ···························(54) 4.1.2 3차원불투과성잠제 주변에서 수위 및 유속에 대한 검증 ···························(57) 4.2 계산조건 ········································································································(60) 4.3 규칙파랑하 수면변동 및 내부유속변동의 특성 ··············································(62) 4.3.1 파고의 분포 ·····················································································(62) 4.3.2 평균유속의 공간분포 ··········································································(69) 4.3.3 연안류의 분포 ···················································································(74) 4.3.4 평균난류운동에너지의 분포 ·······························································(77) 4.4 불규칙파랑하 수면변동 및 내부유속변동의 특성 ·········································(81) 4.4.1 의 분포 ·····················································································(81) 4.4.2 평균유속의 공간분포 ··········································································(86) 4.4.3 연안류의 분포 ···················································································(90) 4.4.4 평균난류운동에너지의 분포 ·······························································(91) 4.5 결언 ···············································································································(93) References ···········································································································(94) 제5장 파-흐름공존장 및 설상사주 형성조건 하에 있는 3차원투과성잠제 주변에서 수면변동 및 내부유속변동의 특성 5.1 계산조건 ········································································································(96) 5.2 규칙파-흐름공존장하 수면변동 및 내부유속변동의 특성 ································(97) 5.2.1 파고의 분포 ·····················································································(97) 5.2.2 평균유속의 공간분포 ········································································(101) 5.2.3 연안류의 분포 ··················································································(102) 5.2.4 평균난류운동에너지의 분포 ······························································(104) 5.3 불규칙파-흐름공존장하 수면변동 및 내부유속변동의 특성 ·····························(106) 5.3.1 의 분포 ····················································································(106) 5.3.2 평균유속의 공간분포 ········································································(108) 5.3.3 연안류의 분포 ··················································································(109) 5.3.4 평균난류운동에너지의 분포 ······························································(111) 5.4 결언 ·············································································································(112) References ··········································································································(113) 제6장 원형유공케이슨 방파제의 월파량, 반사율 및 작용파압에 관한 3차원시뮬레이션 6.1 슬리트케이슨에 작용하는 파압(동압)의 검증 ················································(114) 6.2 계산조건 ·······································································································(117) 6.3 수치해석 결과 ·······························································································(119) 6.3.1 월파량의 비교 ··················································································(119) 6.3.2 반사율의 비교 ·················································································(120) 6.3.3 파압분포의 비교 ···············································································(123) 6.4 결언 ·············································································································(131) References ··········································································································(132) 제7장 결론 7.1 제3장 : 파-흐름 공존장내 2차원잠제 주변의 파랑특성 ································(133) 7.2 제4장 : 3차원투과성잠제 주변에서 수면변동 및 내부유속변동의 특성 ···········(135) 7.3 제5장 : 파 -흐름 공존장내 3차원잠제 주변에서 수면변동 및 내부유속변동의 특성 ········(135) 7.4 제6장 : 원형유공케이슨 방파제의 월파량, 반사율 및 작용파압 ····················(136)Maste

[Cys25]hPTH(1-34) 유도체의 생체 내 및 생체 외 효과

Dept. of Medical Science/석사Recently, an arginine (Arg)-to-cysteine (Cys) homozygous mutation at position 25 (R25C) in mature parathyroid hormone (PTH; 1-84) was reported in a Korean patient with hypoparathyroidism. To clarify whether the high bone mass phenotype observed in this patient is related to the hypoparathyroidism itself or a chronic elevation of mutant PTH, a series of in vitro and in vivo experiments were performed in MC3T3E1, ROS 17/2.8 and SAOS2 cells treated with hPTH(1-34), Cys25hPTH(1-34), Ala1Cys25hPTH(1-34) and Bpa1Cys25hPTH(1-34). The synthesized peptides were then subcutaneously delivered to OVX mice as a daily single-dose regimen. Compared to hPTH(1-34) and Ala1Cys25hPTH(1-34), treatment with Cys25hPTH(1-34) or Bpa1Cys25hPTH(1-34) revealed a decreased cAMP response and pCRE luciferase reporter activity. Although cAMP response was sustained with hPTH(1-34) in MC3T3E1 cells, such response was not observed when cells were treated with the three mutated peptides. Meanwhile, all PTH analogues exhibited ERK phosphorylation and cytoplasmic Ca++ signals comparable to hPTH(1-34). Compared to the control OVX mice, trabecular and cortical bone 2 parameters improved after 6 weeks of respective treatments as follows: hPTH(1-34)(80μg/kg) = Ala1Cys25hPTH(1-34)(80μg/kg) = Cys25hPTH(1-34)(80μg/kg) > Bpa1Cys25hPTH(1-34)(80μg/kg) > hPTH(1-34)(40μg/kg). The increment in RANKL/OPG mRNA ratio after 6 hr treatment of Cys25hPTH(1-34), Ala1Cys25hPTH(1-34) and Bpa1Cys25hPTH(1-34) was less than that was obtained after hPTH(1-34) treatment. In conclusion, the high bone mass phenotype observed in a Korean patient with hypoparathyrodism caused by an Arg to Cys mutation at the 25th residue of mature PTH(1-84), may arise from direct and indirect effects exerted by the mutant PTH itself on bone. Cys25PTH(1-34) could be a potential candidate as a second generation PTHope

An Experimental Analysis on Jet Noise Reduction with Chevron Nozzles on Subsonic Flow

학위논문 (석사)-- 서울대학교 대학원 : 기계항공공학부, 2012. 2. 이수갑.본 연구는 항공기 소음의 주요 소음원 중 하나로 알려진 제트 유동 소음의 저감에 관한 것으로 쉐브론 노즐을 이용하여 아음속 제트 유동에서 발생하는 소음을 줄이고자 하였다. 기존의 쉐브론 노즐에 대한 연구를 보완하고, 소음 저감 효과가 보다 향상된 쉐브론 노즐을 설계하고자 실험적 연구를 수행하였다. 이를 위하여 쉐브론 노즐의 설계 변수를 선정하고 각 변수들에 대한 매개 변수 연구를 수행하였다. 설계 변수는 쉐브론 개수, 길이, 형상으로 선정하였고, 쉐브론 노즐에 대한 추가 연구로서 쉐브론의 크기 변화에 따른 소음 저감 효과에 대해서도 실험을 수행하였다. 실험 결과를 통해 쉐브론 개수가 증가할수록 소음 저감 효과가 커진다는 사실과 특정 쉐브론의 개수에서 그 효과가 최대가 됨을 확인하였다. 쉐브론의 길이 또한 주요한 설계 변수로서 특정 길이 이상 되어야 소음 저감 효과가 있다는 것을 실험적으로 증명하였다. 그리고 쉐브론의 형상은 사각형이나 원형에 비하여 삼각형의 형상이 소음 저감에 좀더 효과적임을 실험을 통해 확인하였다. 본 실험을 통하여 쉐브론의 크기 변화에 따른 소음 저감 효과의 연관성은 찾기가 어려웠지만, 쉐브론 노즐을 설계하는 데 있어서 제트 유동의 소음을 저감하기 위해 고려해야 할 점을 실험 결과를 통해 제안하였다.This study conducts an experimental analysis on jet noise reduction with chevron nozzles. Including base nozzles, ten nozzles are designed and tested at Mach number 0.85. In this experiment chevron count, chevron length, and chevron shape are selected as parametric variables. From the results of this test, as the number of chevron count increase, the nozzle gains reduction of jet noise more. Shortening the chevron length shows ineffectiveness on jet noise reduction. Triangle shape is considered as a proper shape for noise reduction. In this test, it is difficult to find the direct correlation between scaling of chevron nozzle and noise reduction. This study also proposes some considerations on design of chevron nozzle for better noise reduction on subsonic jet flow.Maste

COMPOSITION COMPRISING FARNESOL AND USE THEREOF

A method of increasing PGC-1α gene expression, decreasing PARIS gene expression, or promoting farnesylation of PARIS in a mammalian cell, the method comprising administering an effective amount of farnesol, a pharmaceutically acceptable salt thereof, or a solvate thereof to the cell; and related methods and compositions

COMPOSITION COMPRISING FARNESOL AND USE THEREOF

<p id="p-0001" num="0000">A method of increasing PGC-1α gene expression, decreasing PARIS gene expression, or promoting farnesylation of PARIS in a mammalian cell, the method comprising administering an effective amount of farnesol, a pharmaceutically acceptable salt thereof, or a solvate thereof to the cell; and related methods and compositions.</p&gt

COMPOSITION COMPRISING FARNESOL AND USE THEREOF

A method of increasing PGC-1α gene expression, decreasing PARIS gene expression, or promoting farnesylation of PARIS in a mammalian cell, the method comprising administering an effective amount of farnesol, a pharmaceutically acceptable salt thereof, or a solvate thereof to the cell; and related methods and compositions