Figure 6
From: An inertial mechanism behind dynamic station holding by fish swinging in a vortex street
Forces acting on the fish in the flow composed of the uniform component and the component added by vortices. The vector sum of lift and drag forces has a positive streamwise component assisting fish propulsion. The cross-stream component of the hydrodynamic force leads to fish following an undulatory trajectory with the acceleration shown in Fig. 5.
