Stratification on the Vertical Structure of the Tidal Ellipse and Power Density Estimation in the Larantuka Strait, East Flores Based on ADCP Measurement Data

Abstract

Abstract An understanding of tidal current stratification with a tidal ellipse in coastal oceanography is needed, especially in the development of power density for renewable energy. The movement of the water mass can be converted into power density, by optimizing potential energy (sea level) and kinetic energy (tidal currents). Interaction between tidal current and stratification layer has been of importance to optimize the energy conversion (also turbine selection) at each depth layer. The stratification on the vertical structure can be described by variability of the tidal ellipse, in terms of the semi-major axis, the semi-minor axis, the direction of rotation, ellipticity, inclination angle and phase. ADCP measurement is implemented at Larantuka Strait to examine the tidal behavior on a vertical layer of depth. M2 tidal constituent presents the highest amplitudes among the tidal constituents, predominantly straight line, being the most energetic in Larantuka Strait. M2 constituent the highest major-axis at the near-surface layer when compared with S2 with 243.7 cm/s, 128.9cm/s respectively. Most ellipses rotate clockwise 74° as inclination characterizes the current ellipse orientation. Estimation power density conversion is shown >20.000 kW/m2, with power density average 5014.9 Watt/m2 in spring tide condition. Power density degenerates at the near-surface layer following changes in the depth layer, major-minor axis, inclination angle, and tidal phase of the tidal ellipse.