잠제설치에 따른 만성리해빈에서 해안선의 장기변화 예측

박일흠,강성욱,강태순,Park, Il Heum,Kang, Seong Wuk,Kang, Tae-Soon 해양환경안전학회 2016 海洋環境安全學會誌 Vol.22 No.5

만성리 해안은 중조차 해빈으로 조립한 해저질으로 구성되어 있으며, 외해에 대해 남동쪽으로 열려있어 조석 조류보다 파랑에 의한 해빈변형이 우세하게 나타났다. 파랑은 춘계와 하계에 강하여 유의파고가 2~3m에 달하는 폭풍파가 자주 출현하였으나 추계와 동계는 고파랑이 출현하지 않는 정온한 해상상태를 보였다. 관측된 해안선변화의 계절적 특징은 입사파와 깊은 관계를 나타내었다. 춘계와 하계의 고파랑시에 해안선이 침식하였고 추계과 동계의 정온시에 침식을 회복하였다. 이런 현장자료를 바탕으로 실측해안선자료를 사용하여 해안선변화의 검증수치실험을 수행하였는데, 검증매개변수 $C_1=0.2$와 $C_2=1C_1$일 때 사후예측된 해안선은 실측해안선과의 RMS 오차가 1.26 m 정도로 만족스러웠다. 이 값을 사용하여 잠제와 도류제 등이 완공된 10년 후 만성리 해빈의 해안선을 예측한 결과, 잠제배후역에서 5~15 m 정도 해안선이 전진하며, 잠제배후역 북측에서 5~15 m 정도 해안선이 후퇴하는 결과를 나타내었다. The Manseongri Coast meets the sea on the southeast and is composed of coarse sediment as a mesotidal beach. The waves that strike the beach are stronger than the tides or tidal currents as external forces of beach deformation. Storm waves frequently reach significant wave heights of 2-3m and hit in spring and summer, leaving the sea calm during fall and winter. Incident waves reach remarkable heights that correspond with observed shoreline changes. The shoreline erodes in spring and summer due to these strong waves but recovers in fall and winter as a result of the more moderate waves. On the basis of these observed results, a numerical calibration for experiments on shoreline change was established. Results revealed that according to hindcast data, calculated shoreline changes agreed with the observed shoreline, with a minimum RMS error of 1.26m with calibration parameters $C_1=0.2$ and $C_2=1C_1$. Using these calibration parameters, long-term shoreline change was predicted after the construction of submerged breakwaters and jetties, etc. The numerical model showed that the shoreline would move forward by 5-15m behind the submerged breakwaters and recede by 5-15m north of the structure.

계산시간절약기법이 적용된 수정 POM WAD의 수치실험

박일흠,최흥배,Park, Il Heum,Choi, Heung Bae 해양환경안전학회 2015 해양환경안전학회지 Vol.21 No.1

본 논문에서는 기존의 POM(Princeton Ocean Model) WAD(Wetting and Drying) 모형을 연안역에서 조석조류의 계산에 적합하도록 개경계에서 조석조화상수를 입력하여 사용할 수 있도록 하였고, CTS(Computing Time Saving) 기법을 도입하여 계산시간을 단축할 수 있도록 개선하였다. 이와 같이 수정된 모형은 장방형 내만에 하나의 절점을 갖는 정상파에 대한 해석해 실험과 유속 및 열확산에 대한 수리모형 실험결과와 비교하여 좋은 결과를 얻었다. 그리고 간석지가 발달한 광양만의 현지해역에 이 CTS 기법을 적용하여 계산시간이 39.4% 단축되는 결과를 얻었다. In order to effectively and economically apply the previous POM(Princeton Ocean Model) WAD(Wetting And Drying) to the coastal area, the POM WAD was modified such as the water elevation input of tidal harmonics in the open boundaries was included and a CTS(Computing Time Saving) technique was introduced to the model. The modified model was tested to the standing waves in the rectangular bay and the hydraulic experiments for the flow and heat diffusion in the 3D basin. The numerical results showed a good agreement with the analytical solutions of the standing waves and the observed values by the hydraulic experiments, respectively. And also when the modified model with the CTS technique was applied to Gwangyang Bay of Korea, the computing time was decreased by as much as 39.4%.

수조 수치실험에 의한 말뚝구조물의 항력계수 산정

박일흠(Park, Il-Heum),이근효(Lee, Geun-Hyo),조영준(Cho, Young-Jun) 한국해안해양공학회 2009 한국해안해양공학회 논문집 Vol.21 No.1

RNG k?ε 난류모형이 포함된 3차원 동수역학 수치모형(FLOW-3D^R)을 사용하여 수조 수치실험을 통한 항력계수 산정 가능성을 검토하였다. 물리적 실험으로 항력계수가 알려져 있는 말뚝구조물에 대하여, 사각형 말뚝구조물의 수치해에 의한 항력계수값이 1.34~1.52로 물리적 실험값인 1.3~1.5의 범위와 매우 유사한 결과를 보였다. 원형 말뚝구조물은 0.5<h/D<3.5의 범위에서 수조 수치실험치가 0.75~0.78 정도로서 물리적 실험치와 비교적 잘 일치하였다. 그리고 항력계수값이 알려지지 않은 열을 이룬 말뚝구조물의 경우 항력계수값은 구조물 간의 간섭으로 단일 구조물에 비해 항력계수가 크게 나타났으며, 각 구조물간의 거리비가 작아짐에 따라 구조물이 받는 항력계수값은 증가하는 양상을 보였다. A possibility of the drag coefficient estimation in numerical water basins was discussed where the numerical solution were calculated by the 3-dimensional hydro-dynamical model (FLOW-3D^R) with the RNG k?ε turbulence model. On the known cases of the drag coefficients for a rectangle, the numerical drag coefficients got 1.34~1.52 and the wind tunnel values were 1.3~1.5. For a cylinder, the numerical values were calculated as 0.75~0.78 in the range of 0.5<h/D<3.5. Therefore the numerical results showed a good agreement with the physical experiment in a cylinder body runs. On the unknown cases of a row of rectangle, the drag coefficients were more increase than the cases of single body because of the interaction of other structures. And also the drag coefficients had large values as the distance interval ratio of the structures more and more decrease.

해면매립에 따른 도구 해빈의 해안선변화 장기예측

박일흠(Il Heum PARK),이문옥(Moon Ock LEE) 전남대학교 수산과학연구소 1999 수산과학연구소논문집 Vol.8 No.-

The long term prediction of shoreline change around coastal structures due to a reclamation in Dogu Beach is performed. In the calculation of shoreline change, it is important to estimate the breaking wave directions and heights. To solve these problems, the mild slope equation of elliptic type is adopted. The total longshore sediment transport rates are considered with the spatial distribution of wave height and the interaction of seawall. The result of shoreline change shows a qualitatively good agreement with the pattern of wave-induced current. After 5 years, the maximum net change between before and after reclamation increases to be 6m whinin 100m of coast line of the shadow zone.

하천의 영향을 받는 동해안 대왕암 주변의 해안선변화

박일흠 ( Il Heum Park ),이영권 ( Young Kweon Lee ) 한국도서(섬)학회 2010 韓國島嶼硏究 Vol.22 No.1

Bonggil-ri Beach located in the main historical site, Daewangam, has been seriously occurred the beach change in accordance with the variation of sediment rate from river and the construction of large-scale structures such as Wolseong Nuclear Power Plant. In order to investigate the present state of erosion and deposition for this coast and the influence of erosion and deposition caused by the construction of structures, field observations such as long term analysis of aerial surveying photographs and observation with seasonal changes of shoreline and beach profiles were conducted and the results were analyzed. In the basis of these observed data, the long term beach changes were predicted by the numerical model of shoreline change that considered the effect of river, where the empirical parameters were verified with field data. The seasonal variation of beach deformation was strongly represented in Bonggil-ri Beach. The shoreline change was mainly dependent upon the movement of sand spit in the north coast from Daewangam and the south coast was comparatively shown a stable state. In the verification simulations of shoreline change, the calibration parameters to estimate the total longshore sediment transport rate were the lowest errors with, and. Both forward and backward movements of shorelines in the beach were sensitively responsed in accordance with the sediment rate from Daejong Stream and the change of external forces by the structures near the beach.

광양만의 섬형태 매립지 주변에서 해수유동과 해수교환

박일흠 ( Il Heum Park ),이문옥 ( Moon Ock Lee ) 한국도서(섬)학회 2008 韓國島嶼硏究 Vol.20 No.1

잔교식 항만구조물 주변에서 해수유동의 평가

박일흠(Il Heum Park) 한국해양환경·에너지학회 2004 한국해양환경·에너지학회지 Vol.7 No.2

영일만에서 해면매립에 따른 반사파의 영향

박일흠(Il Heum PARK),이동수(Dong Soo LEE),이문옥(Moon Ock LEE) 전남대학교 수산과학연구소 1999 수산과학연구소논문집 Vol.8 No.-

The effect of reflection wave due to a reclamation in Youngil Bay is discussed. The numerical experiments are performed with the design waves of 50 years frequency. The system of grid nets is composed of large and small fields. The mild slope equation of elliptic type is adopted in the large field and the unsteady mild slope equation of hyperbolic type is also applied to the small field. The energy equation of wave breaking and bottom friction is incorporated with each other to estimate the energy dumping. After reclamation, the maximum change of wave height increases up to the 1.4 times. But the effective boundary of reflection wave is restricted within a small area.

신지명사십리 해수욕장에서 현장조사에 의한 해빈변화와 퇴적물이동 특성

정승명,박일흠,Jeong, Seung Myong,Park, Il Heum 해양환경안전학회 2021 해양환경안전학회지 Vol.27 No.5

신지명사십리 해수욕장에서 해빈침식의 원인을 파악하기 위해, 2019년 3월부터 2020년 3월까지 조석, 조류 및 파랑과 같은 외력과 표층퇴적물에 대한 현장조사가 계절별로 수행되었다. 그리고 이들 외력에 반응하는 해빈의 변화양상을 파악하기 위해, 정기적으로 해안선 및 해빈표고가 측량되었고, 과거에 간헐적으로 수행되었던 측량자료도 분석에 활용되었다. 대상해역에서 조류는 해빈변화에 영향을 줄 만큼 충분하지 않았으나, 남측으로 열려있는 이 해역에서 유의파고 1m 이상의 입사파들은 모두 S ~ SE 파향으로 춘하추계에 출현하였으며, 유의파고 2m 이상의 고파랑은 하추계에 태풍의 영향으로 나타났다. 이에 따라 태풍의 영향이 2년 동안 없었던 2018년 7월의 해빈면적은 2019년 3월에 비해 30,138m² 증가해 있었고, 이후 2차례의 태풍의 영향을 겪었던 2020년 3월은 해빈면적이 61,210m²가 줄어든 것으로 나타났다. 그리고 2018년 7월 이후 2차례의 태풍 내습이 있었던 2019년 3월은 5.4%의 해빈체적이 감소한 상태였고, 이후 2019년 9월까지 다시 2차례의 태풍내습에 의해 해빈체적이 7.3% 감소하였으며, 2020년 3월은 해빈체적이 4.4% 감소로서 추동계동안 다소 회복되는 경향을 보였다. GSTA에 의한 퇴적물 이동벡터는 해빈중앙의 소하천으로 부터 토사가 약하게 유입되며, 서측해빈에서 이동경향은 두드러지게 나타나지 않으나, 동측해빈에서 육상역의 토사가 바다쪽으로 그리고 동측에서 서측으로 퇴적물이 이동하는 경향이 아주 우세하게 나타났다. 이러한 퇴적물 이동경향벡터는 해빈에 대해 반시계방향으로 24° 기울어져 있어 연평균파향의 파랑이 입사할 때 서향의 해빈류가 발달하는 것으로 설명할 수 있었다. 이에 따라 서측해빈역은 모래가 풍성하지만, 동측해빈역은 표사공급원의 부재로 자갈이 드러나고 곳곳에 사구포락이 발생하는 것과 같은 침식이 심각하였다. 따라서, 이같은 토사이동구조를 가진 동측해빈역에 양빈과 같은 새로운 표사원을 조성하고, 동측해안 끝단역에서 입사파를 저감시키는 것과 같은 노력이 필요할 것으로 판단되었다. To evaluate the causes of beach erosion in Sinji-Myeongsasimni Beach, external forces, such as tides, tidal currents, and waves, were observed seasonally from March 2019 to March 2020, and the surface sediments were analyzed for this period. In addition, the shoreline positions and beach elevations were regularly surveyed with a VRS GPS and fixed-wing drone. From these field data, the speed of the tidal currents was noted to be insufficient, but the waves were observed to af ect the deformation of the beach. As the beach is open to the southern direction, waves of heights over 1 m were received in the S-SE direction during the spring, summer, and fall seasons. Large waves with heights over 2 m were observed during typhoons in summer and fall. Because of the absence of typhoons for the previous two years from July 2018, the beach area over datum level (DL) as of July 2018 was greater by 30,138m² compared with that of March 2019, and the beach area as of March 2020 decreased by 61,210m² compared with that of March 2019 because of four typhoon attacks after July 2018. The beach volume as of March 2019 decreased by 5.4% compared with that of July 2018 owing to two typhoons, and the beach volume as of September 2019 decreased by 7.3% because of two typhoons during the observation year. However, the volume recovered slightly by about 3% during fall and winter, when there were no high waves. According to the sediment transport vectors by GSTA, the sediments were weakly influxed from small streams located at the center of the beach; the movement vectors were not noticeable at the west beach site, but the westward sediment transport under the water and seaward vectors from the foreshore beach were prominently observed at the east beach site. These patterns of westward sediment vectors could be explained by the angle between the annual mean incident wave direction and beach opening direction. This angle was inclined 24° counterclockwise with the west-east direction. Therefore, the westward wave-induced currents developed strongly during the large-wave seasons. Hence, the sand content is high in the west-side beach but the east-side beach has been eroded seriously, where the pebbles are exposed and sand dune has decreased because of the lack of sand sources except for the soiled dunes. Therefore, it is proposed that efforts for creating new sediment sources, such as beach nourishment and reducing wave heights via submerged breakwaters, be undertaken for the eastside of the beach.

파랑변형 및 해빈류에 대한 Boussinesq 모형의 적용성 검토

조영준,박일흠,Cho, Young-Jun,Park, Il-Heum 해양환경안전학회 2010 해양환경안전학회지 Vol.16 No.2

Boussinesq 모형을 이용하여 규칙파 조건(Regular wave condition)에서 파랑변형 및 해빈류의 수치모의를 하였다. 파랑변형의 수치결과는 선행 연구에 의한 수리실험 결과와 비교하여 매우 좋은 일치를 보였으며, 검증한 파랑변형 결과를 바탕으로 충분히 안정한 상태 이후의 해빈류를 계산하여 예측하였다. 모형의 현장 적용성을 위해, 실규모해역에서 관측한 선행 연구의 현장자료와 비교하였으며, 파랑변형의 수치결과는 현장자료와 비교적 양호한 일치를 보였다. 해빈류의 수치결과는 연안사주가 발단된 지역에서 다소 과소평가 되었지만, 전반적으로 해빈류의 공간적 분포에 대하여 정도 있게 예측한 것으로 여겨진다. In the present study, wave deformation and wave-induced current were calculated under the regular wave conditions using the Boussinesq model. The model results of the wave deformation showed good agreements with the preceeding laboratory experiments of others. The wave-induced current of the fully developed sea state was calculated. For field application of model, the preceeding field data by others in the real scale of the water area were compared, the numerical result of wave deformation showed a relatively good agreement with the field data. Although the numerical result of wave-induced current was underestimated over the longshore bar developed area, the Boussinesq model is generally suitable to predict the wave-induced current.