Implications of Structural and Buoyancy Constraints on the Design of Marine Hydrokinetic Energy-Harvesting Kites

Marine hydrokinetic kites have the potential to efficiently exploit energy from the ocean by extracting energy from currents. To ensure efficiency in energy harvesting, these devices must be optimally sized for the operating conditions they will be deployed under. Kites experience significant structural loading on their wings due to their high flight speeds. It follows that the allowable sizing of these kites is driven by a structural constraint on the wing's deflection, which is dictated by the lift forces on the wing, and the need to satisfy neutral buoyancy, which limits the mass and rigidity of the wing. For this work, a thorough study of how the structural constraint activity changes under different operating conditions, and how this affects design optimization feasibility was performed. Additionally, the feasible design range was studied for various kite payloads. The results indicate that as the wing span increases, the structural constraint activity increases. Moreover, as flow speed increases and the distance from the kite's base station to centerpoint of the kite's path decreases, the structural constraint is unable to be satisfied while meeting the neutral buoyancy requirement. Furthermore, the characterization of when the optimization becomes infeasible as the payload changes was studied.