Novel Approach to Aquatic Bodies Locomotion: Part 3: Pectoral Fin Source of Power

The area of fish locomotion is infested with the prevailing and dominating model which violates the first and second laws of thermodynamics. The prevailing model avers that von Karman’s vortices are responsible for fish aquatic bodies propulsion. For the first time, this model was scrutinized and the conceptional errors were exposed in the first paper of this series. In the second paper in this series, the long construction process of building models started which describes the various effects of the tail (caudal fin) and other fins. The current paper inserts science into the modeling of a specific category of pectoral fins. The fourth paper deals with the undulating fins and the reverse “tail” propulsion (like the Trigger fish). Here, the focus is on the pectoral fin. The understanding how fin works and the significance of the various parameters is examined. It seems that if the fin moves in the same speed back and forth, the net thrust is zero since the fin cannot bend during return of the fin. The most intuitive idea to explain the locomotion is the change of the cross area. This idea might be more correct for diving birds like puffins which are not exactly aquatic creatures. For most aquatic creatures like fish, who spend almost all of the time in the water, this statement is not correct. It turned out that the rotating and undulation of the fin do help to improve or create propulsion but not significantly. Yet, the main contributors are different mechanisms. The main mechanisms for most fishes that control the pectoral fin propulsion are the different angular velocity at distinct phases, and the operation angles in the yaw direction range. This explanation becomes obvious after checking the model, but remember that for the last over 100 years of research in this area, no one proposed or considered it.Another breakthrough in the area of fish locomotio