pectoral fin splash
CFD-analysis of the flow around a humpback whale's pectoral fin - start: 2004
whale pages

Why does the humpback whale (megaptera novaeangliae) have knobs (tubercles) on his pectoral fin?

Welcome to our slightly different whale-pages!

These pages accompany our science-project of conducting simulations of the flow around the pectoral fins of a humpback whale.

Ulterior motives and pivotal questions of this project

The project described here was launched to answer a simple question:

Why does the humpback whale have humps on his pectoral fins?

Our opener-photo shows the pectoral fin of the whale (among non-biologists better known as the flipper). The peculiar knobs (so-called tubercles) at it's leading edge are easily discernible. These tubercles are unique to humpbacks, as is the flipper's enormous length of up to one third of the whales body. An assumption suggests itself: Maybe nature gave the genus megaptera this feature for a reason. 

Unlike the fluke (tail fin) the flipper contains bones similar to that of a human arm. It seems to be equally agile and flexible, too - which is a royal pain in the bum if you want to conduct flow simulations by the way.

Despite its size (10-15m, 25-45t) the humpback whale is a versatile and dexterous swimmer. The extraordinarily long flippers seem to play an important role with that. Thanks to their sophisticated hydrodynamic layout they allow manoeuverability that other, similarly sized whales cannot match. The conclusion suggests itself that the tubercles on the flippers play a crucial role in the fluid mechanic quality of this one-of-a-kind appendix. The humpback whale would suffer severely from having a suboptimal shape as he migrates approximately 8000km per year, much of the distance without feeding-opportunities.

From the flow-physicists point of view the flipper gives rise to a number of interesting questions:

  • The knobs seem to be beneficial to the hydrodynamics of the whale. Is it possible to confirm this hypothesis scientifically?

  • Assuming a beneficial hydrodynamic mechanism can indeed be identified, are there technical applications that would profit from it, e.g. improved airfoils or turbine blades?

We are always looking for pictures!
If you can provide us with pictures or photographs of HBW pectoral fins, kindly mail them to: (max. size allowed 5 MB)
Thanks a lot!

News: BCBMM Cape Town
Part of our work was presented by Jens at the 17th BCBMM in Cape Town.

Click -> here for further information!

*** translation-update ***
work in progress...

As promised in Capetown we're currently translating our page to English - but it turns out to be quite an effort. If you have any suggestions or questions feel free to contact us by mail. Thanks.

by Kirsten 2006