The Influence of Leading-Edge Tubercles on the Sheet Cavitation Development of a Benchmark Marine Propeller

Abstract

Cavitation is an undesirable phenomenon in the maritime industry as it causes damage to the propeller, degrading hydrodynamic performance and increasing the subsequent underwater radiated noise (URN). Therefore, mitigating cavitation on marine propellers is an important area of research in order to reduce carbon emissions emitted from the shipping industry and reduce the rate at which ocean ambient noise levels are increasing. The Humpback whale has provided inspiration to research in the fluid-structure interaction field due to the presence of leading-edge (LE) tubercles on the pectoral fins that allow it to perform acrobatic maneuvers to catch prey. This paper assesses the cavitation containment capability of the LE tubercles on a benchmark marine propeller in both heavy and light cavitating conditions using commercial code STAR-CCM+, unsteady incompressible Reynolds-averaged Navier Stokes (RANS) solver and the Schnerr-Sauer cavitation model to quantify the sheet cavitation present over a range of operating conditions. In summary, in heavy-cavitating conditions, a reduction in sheet cavitation with the inclusion of LE tubercles was observed to a maximum value of 2.75% in all operating conditions considered. A maximum improvement of 3.51% and 1.07% was predicted in propulsive thrust and hydrodynamic efficiency, respectively. In light cavitating conditions, although in some conditions a reduction in cavity volume was observed, this did not result in an improvement in hydrodynamic performance.

Study on Applicability of Energy-Saving Devices to Hydrogen Fuel Cell-Powered Ships

“…The reduction in cavitation results in a reduction in the fluctuating thrust and torque from the propeller, which would be an extra benefit to the hydrogen drivetrain with a steadier load on the shaft compared to the baseline design, reducing negative impacts on the fuel cell. The TAPs have a wide range of applications, being applied to open propeller blades [101] as well as ducted propeller blades [100], with the possibility to provide benefits to various types of marine craft. Further research through model-scale test campaigns and numerical, full-scale investigations in the behind-hull condition is required to confirm the propulsive efficiency improvement and quantity the energy savings in a realistic setting.…”

Cavitation funnel effect: Bio-inspired leading-edge tubercle application on ducted marine propeller blades

“…Additionally, the influence of LE tubercles on marine propellers has been investigated (Charalambous and Eames., 2019;Ibrahim and New., 2015;Stark and Shi., 2021b). Ibrahim and New., (2015) conducted a numerical investigation using CFD to conclude that LE tubercles can improve the total raw power output of the propulsive device in non-cavitating conditions, although an increase in torque results in a lower propulsive efficiency.…”

“…Charalambous and Eames., (2019) used numerical methods to show at a single operating condition, sheet cavitation is influenced by LE tubercles. Stark and Shi, (2021b) showed using CFD that leading-edge tubercles can create a cavitation funnel/fencing pattern which redistributed and reduced the sheet cavity volume present on the propeller blades resulting in an improvement in hydrodynamic efficiency.…”

Marine Ducted Thruster Underwater Radiated Noise Control Through Leading-Edge Tubercle Blade Modifications - a Numerical Hybrid Approach

“…This ability is aided by the small bumps or leading-edge (LE) tubercles located on the pectoral fins of the mammal [7]. LE tubercles have been researched on applications such as aero/hydrofoils, tidal turbines, rudders and marine propulsors [8][9][10][11][12][13][14][15][16]. LE tubercles produce counter-rotating vortex pairs which can influence the local flow-field, and the tubercle modifications have shown to alter the cavitation development on a variety of applications.…”