TY - CONF
TI - The effect of variation of cross-sectional geometry on the performance of a top-hinged wave energy converter
AU - Edwards, E
AU - Whitlam, C
AU - Hughes, J
AU - Hann, M
AU - Yue, D
AU - Greaves, D
T2 - 39th International Workshop on Water Waves and Floating Bodies (IWWWFB Scotland, 2024)
AB - Geometry optimisation of a wave energy converter (WEC) is an excellent way to improve performance of the WEC, since wave-structure interaction and the resulting forces depend strongly on the geometry (Garcia-Teruel & Forehand 2021). In a recent study, a geometry optimisation of a top-hinged WEC was performed, wherein the objective functions were to (i) maximise power and (ii) minimise the power take-off (PTO) force, forming a multi-objective optimisation. The latter objective function was introduced because the PTO equipment can incur up to 50% of the total capital expenditure of the WEC (Bedard et al. 2004). In this previous study, a uniform cross-sectional area for the top-hinged WEC in the x − z plane was considered, as shown in figure 1a. Results were shown to be consistent with relevant far-field theory of radiating waves. It was shown that by introducing minimisation of the PTO force as an objective function, we could significantly lower the PTO force without significantly reducing the extractable power.In the present study, we look to generalise the geometry optimisation further by relaxing the requirement of uniform cross-sectional area. The shape of the x − y plane geometry is changed, and the performance of the WEC is studied (i.e., the extractable power and PTO reaction force).The methodology is outlined in Figure 1. The WEC is a top-hinged WEC, whereby the main WEC absorber is attached to a hinge point (O) via a rigid arm and thus restricted to pitch motion only. In the previous study, we defined curves c1 and c2 to describe the x−z plane curves defining the front and rear face of a top-hinged WEC with uniform cross section. We performed a multi-objective optimisation to find the optimal geometries (that is, the parametric expressions for the curves c1 and c2, as well as parameters r1 and r2, which define the horizontal lengths, as shown in Figure 1a), which (i) maximise power, and (ii) minimise PTO force. Extending this work, here we select five representative cross-sectional areas from the previous optimisation’s Pareto Front of optimal solutions, distinguished by colour in Figure 1c. In this analysis, we define curves c3 and c4 to represent a change in the cross-sectional area along the width of the device. We look at the effect of changing parameters f2 and g2, which are the second-order coefficients of the polynomial basis functions defining c3 and c4, respectively, on the power and force.
DA - 2024/04//
PY - 2024
SP - 4
PB - IWWWFB
UR - http://www.iwwwfb.org/Workshops/39.htm
LA - English
KW - Wave
KW - Oscillating Wave Surge Converter
KW - Hydrodynamics
KW - Performance
ER -