해일 침수범람지역 예측기술 및 재해도(Hazard Map) 작성기술 개발

심재설,윤종주,Sim, Jae-Seol,Yun, Jong-Ju 한국해안해양공학회 2013 해안과 해양 Vol.6 No.1

해양에너지 및 해양공간 활용의 신개념

심재설,정진용,Sim, Jae-Seol,Jeong, Jin-Yong 한국해안해양공학회 2012 해안과 해양 Vol.5 No.2

신기술 - 해상용 풍력발전기 시공을 위한 가설프레임 및 Jacking System 개발

심재설,우찬조,Sim, Jae-Seol,U, Chan-Jo 한국어촌어항협회 2013 어항어장 Vol.104 No.-

Boussinesq 방정식 모델의 수치잡음 제거를 위한 저파수 통과 필터에 대한 고찰

전인식(Chun, In-Sik),심재설(Sim, Jae-Seol) 한국해안해양공학회 2007 한국해안해양공학회 논문집 Vol.19 No.5

Boussinesq 방정식에 의한 파랑전파의 계산과정 중 파랑의 비선형 상호작용 및 쇄파발생에 의하여 수치잡음이 흔히 발생하며 이 잡음을 적절히 제어하지 않을 경우 해가 급속히 발산하게 된다. 본 연구에서는 계산 중간과정에 주기적으로 적용하여 수치잡음을 제거하기 위한 세가지 형태의 저파수통과 필터(FFT 필터, 가우스 필터, 그리고 Shapiro 필터)의 특성에 대하여 고찰하였다. 경사면 파동장에 대한 기존의 수리실험 결과와 본 수치해석 결과를 비교하고 각 필터의 잡음 제거효과, 주 시그널의 보존성, 그리고 계산 소요시간에 대하여 검토하였다. 그 결과, Shapiro 필터의 매개변수(필터 요소수와 통과수, 그리고 필터적용주기)를 적절히 설정함으로써 계산의 정확성과 효율성을 잘 달성할 수 있는 것으로 나타났다. 적정한 매개변수 선정을 위해서는 다소의 시행착오적 계산이 요구되나 대체적으로 필터 요소수 4에 대하여 50이내의 필터 통과수와 100~200 시간스텝 정도의 적용주기가 타당한 것으로 판단된다. In the calculation of wave propagation by Boussinesq equation model, it is very common to experience numerical noises generated from nonlinear interaction and breaking wave occurrence, and the numerical solution is rapidly diverged unless the noises are properly controlled. A comparative study was here undertaken for the characteristics of three different lowpass filters (FFT filter, Gaussian filter and Shapiro filter) which are all designed to be applied to the interim results of numerical calculation. The numerical results obtained with application of respective filter techniques were compared with the results of an existing hydraulic experiment for the aspects of noise suppression, conservation of main signal and altering time. The results show that the Shapiro filter can be best applied with optimal choices of its element number, pass number and filtering tune interval. The combination of the number of filter element off, pass number of 50 or less, and application interval of 100 to 200 time steps generally showed good performance in both accuracy and efficiency of the numerical calculation.

Boussinesq 방정식을 이용한 수중 천퇴에서의 파랑변형 및 파랑류 계산

전인식(Chun In Sik),성상봉(Seong Sang Bong),김귀동(Kim Gui Dong),심재설(Sim Jae Seol) 대한토목학회 2005 대한토목학회 학술대회 Vol.2005 No.10

수중 천퇴에서의 쇄파거동 예측을 위한 Boussinesq 방정식 모델의 적용

전인식(Chun, In-Sik),김귀동(Kim, Gui-Dong),심재설(Sim, Jae-Seol) 한국해안해양공학회 2006 한국해안해양공학회 논문집 Vol.18 No.2

본 연구에서는 수중 천퇴부에서 쇄파가 발생할 시 주변 파랑과 파랑류의 평형계를 직접 해석할 수 있는 Boussinesq 방정식 모델을 수립하고 이 결과를 수리실험 결과와 비교하였다. 사용된 쇄파모델은 쇄파 감쇠항을 모멘텀 방정식에 포함시키는 일종의 와점성 계수 모델이며, 관련된 쇄파 매개변수의 적정 값들을 Vincent and Briggs (1989)의 규칙파 실험자료를 이용한 민감도 분석을 통하여 결정하였다. 구해진 적정 매개변수 값들을 가지고 수치해석을 수행하여 이 결과를 불규칙파 실험결과와 이어도 천연암초의 수리모형실험 결과와 비교하였다. 그 결과, 천퇴부 하류 쪽에 파 진행방향으로 향하는 강한 쇄파유도류가 발생함에 따라 저파고대가 형성되며 전반적으로 계측파고의 분포와 유사함을 확인하였다. In the present study, a numerical model using Boussinesq equation is set up to predict the interacted equilibrium between waves and their induced currents in the occurrence of breaking waves over an underwater shoal, and the numerical results are compared with results of existing hydraulic experiments. A sensitivity analysis has been done to find out appropriate values of breaking wave parameters with the result (regular wave case) of Vincent and Briggs (1989)’ experiment. Then the numerical model is applied to the irregular wave cases of the experiment and the hydraulic model test of Ieodo which is a natural undersea shoal. The results show that a strong current forms in the wave direction at the downstream side of the shoals, causing the attenuation of wave heights there. The calculated wave heights generally show a similar pattern with the measured data.

수중 천퇴 인근에 설치된 해양구조물에 작용하는 유체력 결정에 대한 고찰

전인식(Chun, In-Sik),민인기(Min, In-Ki),심재설(Sim, Jae-Seol) 한국해안해양공학회 2007 한국해안해양공학회 논문집 Vol.19 No.2

파랑이 수중 천퇴부를 넘어 쇄파하는 경우 파고는 작게 형성되나 강한 이차적 흐름 (쇄파유도류)이 발생한다. 따라서, 임의의 해양구조물이 쇄파대에 위치할 경우에는 단순히 가시적인 파고에만 근거한 파력산정은 과소설계를 초래할 가능성이 있으며 구조물의 안정설계를 위해서는 쇄파유도류의 유속이 가미된 상태에서의 유체력을 정확히 산정하여 반영할 필요가 있다. 본 연구에서는 Boussinesq 방정식 모델을 이용하여 쇄파대내에서의 파고분포와 쇄파유도류를 계산하는 기법을 수립하였으며 과거에 수행하였던 이어도 해양과학기지의 수리모형실험 (1/120)의 모델영역에 적용하였다. 이 계산결과를 이용하여 모형구조물에 작용하는 유체력을 계산하고 수리모형실험 결과와 비교함으로써 쇄파유도류의 영향을 정량적으로 평가하였다. When waves propagating over an underwater shoal break at the top of the shoal, wave heights are drastically decreased in the downstream breaking zone, but a secondary current shooting downstream with strong velocity can be induced by the breaking waves themselves. In the case that an offshore structure is placed in the breaking zone, the estimation of wave farce purely based on the visible wave height may cause an under-design of the structure. Thus, for the safe design of the structure, the breaking wave induced current should be necessarily considered in the comprehensive estimation of design load. In the present study, Boussinesq equation model to calculate the wave height distribution and breaking wave induced current was set up and applied to the scheme of a hydraulic model test previously undertaken. Based on the results of the Boussinesq model, fluid forces acting on the model structure were calculated and compared with the experimental results. The importance of the breaking wave induced current was quantitatively assessed by comparing fluid forces with or without current.

Single Line Theory를 적용한 안목 해변 잠제에 의한 해안선 변화 모델링

장연식(Yeon S. Chang),바스 후이스만(Bas Huisman),위베 데 보어(Wiebe de Boer),심재설(Jae seol Sim),로버트 멕컬(Robert McCall),도기덕(Ki deok Do),유제선(Je seon Yoo) 한국연안방재학회 2017 한국연안방재학회지 Vol.4 No.4

Since a submerged breakwater (SBW) was built and the beach was nourished at Anmok in the east coast of Republic of Korea at October, 2014, the shoreline in the lee of the SBW has accreted about 25 m during the first seven months after construction. The shoreline evolution showed two distinct patterns which were studied in this paper. A strong local accretion behind the submerged breakwater was observed in March 2015 and a smoother shoreline with accretion that extended up to Gangneung Harbor breakwater in May 2015. The UNIBEST coastline model (developed at Delft Hydraulics) was applied for the investigation of the observed shoreline undulation patterns which were generated by alongshore sediment transport gradients that were induced by the SBW and nourishment. Nearshore wave conditions were computed for this purpose at nine locations in the nearshore with the Delft3D-wave model. Two detailed wave scenarios with different crest height of the SBW were taken into account to represent the transmission of waves at the SBW which were validated with field measurements. The coastline model is able to reproduce the observed shoreline evolution patterns when wave transmission at the SBW is represented well, which is the case for a wave scenario with a lowered effective crest level of the SBW. Initially, accretion takes place predominantly at the northern side of the scheme, which was similar to the observed shoreline shape of the March 2015 situation. This local accretion is a result of the low sediment transport capacity behind the SBW due to sheltering of the wave energy, which initially hinders the redistribution of sediment to the South (i.e. area in-between Gangneung Harbor and SBW). After some months, a redistribution of sediment will take place behind the SBW which results in a smoother shoreline pattern which is similar to the May 2015 situation. The rate of change of the shoreline accretion is controlled by the absolute transport rates at the coast (i.e. wave energy), but is often of lesser importance since an adjustment towards a new shoreline equilibrium may take place within relatively short time scales (i.e. months to a few years). In addition to the wave energy, it was found that the relative angle of the incoming waves (α) is most relevant for the final shoreline shape. The shoreline evolution at future SWB structures may therefore be predicted by precisely estimating the α directly after construction of the SBW.