20-11-2025 - Lecture Hall L

PhD presentations

Can blowing water make a boat fly?

Vasu Krishnan

Hydrofoil craft have gained significant attention in recent years because they offer fast and efficient transport, both in dense urban waterways and in offshore environments. A key challenge for commercial use, however, is ensuring comfortable and safe operation in both calm water and waves. This requires maintaining a stable ride height, which in turn demands an effective control strategy.
One promising lift-control approach uses the Coandă effect: water is blown from a modified trailing edge of the hydrofoil to increase lift. While this mechanism has been studied under steady, idealised conditions, its behaviour in waves remains largely unknown. This research investigates how unsteady inflow conditions—specifically waves—affect the forces on the hydrofoil and the performance of the blowing-based lift-enhancement mechanism.
Current experiments show that the blowing mechanism increases lift in both steady water and wave conditions, and that the increase remains approximately linear within the tested range. However, challenges remain when applying this approach as a practical control method, particularly due to limitations in current theoretical models, which do not fully capture the complexities observed in real operating conditions.