층별 조류 관측자료를 이용한 장죽수도 내 조류 프로파일 특성 분석

Analysis of Vertical Profile Characteristics in Jangjuk Strait using Layered Tidal Field Measurement Data

Various mathematical models have been proposed to estimate the vertical tidal current profile. However, because the parameters of these models depend on specific site conditions such as seabed conditions and viscosity, it is recommended to estimate them using field-measured data. In particular, tidal current energy sites with fast tidal velocities exhibit different vertical tidal current profile characteristics from general sea areas, making it essential to estimate these profiles using field-measured data for practical purposes. In this study, layered tidal currents were measured over two months using an acoustic Doppler current profiler to analyze the vertical tidal current profiles at two sites in Jangjuk Strait, a candidate site for tidal current energy. Based on the field-measured data, the profiles were fitted using power law and logarithmic profile models, and the parameters were estimated for both flood and ebb tides with a velocity bin set at 1 m/s intervals. The analysis results indicated that at JSD-1, the power law parameter was estimated to be 7.50 during flood tide and 9.49 during ebb tide, with an average bed roughness of 0.42. Additionally, the roughness length, which represents seabed roughness in the logarithmic profile, was estimated at 0.022 m during flood tide and 0.011 m during ebb tide, while the friction velocity was estimated at 0.115 m/s during flood tide and 0.073 m/s during ebb tide. At JSD-2, the power law parameter was estimated at 7.40 during flood tide and 10.30 during ebb tide, with an average bed roughness of 0.41. Additionally, the roughness length was estimated at 0.020 m during flood tide and 0.005 m during ebb tide, while the friction velocity was estimated at 0.118 m/s during flood tide and 0.074 m/s during ebb tide. Finally, a correlation analysis between the parameters confirmed a positive correlation between the depth-averaged tidal current velocities and friction velocities. Tidal current energy sites display characteristics different from other sea areas; hence, it is necessary to consider field conditions when analyzing layered tidal characteristics or conducting numerical ocean modeling.