Application of a Humpback Whale Fin as a Rudder

Abstract

With ships growing larger and larger for each generation the need for better manoeuvrability increases. Previous studies have shown that redesigning the leading edge of the rudder will increase the manoeuvrability. A method for increased manoeuvrability is by mimicking the tubercles on the leading edge of the humpback whales flipper. The tubercles on the leading edge of the flipper will delay the separation, increasing the lift-to-drag ratio which in turn will yield a highly efficient rudder, making manoeuvring easier. A parametric foil with the possibility to easily change the foils chord length, span width and thickness as well as the tubercles amplitude and wave length. Three different validation studies were conducted to confirm that it was possible to recreate the results from previous studies. The investigation conducted by this thesis investigated 16 different foils with different characteristics to see which foil yielded the highest lift-to-drag ratio. From the investigation of the foils it can be concluded that tubercles on the leading edge has a negative influence on the lift-to-drag ratio. Contradicting to our expectations was the foil that yielded the highest lift-to-drag ratio the foil with a flat-leading edge. However, further investigation of the foils at an angle of attack =0° needs to be conducted to examine the drag coefficient. If a foil, yields a high lift coefficient for high angles of attack while not increasing the drag for 0° it might still be beneficial to use that foil. This thesis is the first, to the authors knowledge, computational simulation to have as many wave lengths as 21.