Numerical and experimental investigation on the behaviour of biomimetic tubercles in a fully turbulent flow channel at high Reynolds numbers

Biomimetic tubercles, inspired by those on humpback whales (Megaptera Novaeangliae), have been shown to have a remarkable effect on the flow feature around a foil structure when applied to its leading edge.
The effect of biomimetic tubercles on marine vessels is addressed in the present study through their capacity to manipulate the flow characteristics on the flat surfaces to which they are attached. A numerical investigation was conducted to identify the most relevant combinations and configurations of tubercles for physical testing in the Fully Turbulent Flow Channel (FTFC) at the University of Strathclyde. The CFD simulations were conducted using a commercial RANS code to determine the behaviour of tubercles on a flat panel and their interactions in various configurations.
The tubercles configurations were subsequently tested at high Reynolds numbers in an extensive experimental campaign in the FTFC. The results were corrected for the 3D effect of tubercles in the channel’s measuring section, with the correction factors being extrapolated from the CFD simulations.
The tubercles’ effect on the friction coefficients of the panels was studied and compared to the numerical predictions. The EFD and CFD results could not be directly compared, due to the intrinsic differences between the two models, however, the consistency of results allows the use of RANS simulations to calculate the correction factors to be applied to the EFD results.
The physical tests proved that the tubercles have a generally positive effect on the flat panels, with their distribution and combination affecting the results more than their total number.