FIGURE 11.

Quantification of fluid profiles in the bifurcation interray zone (BI) and the primary interray zone (PI), at four equidistant positions of the fin model during a complete period. (A–D) Four key points were selected along a full period of oscillation as indicated in the left column. A schematic depiction of the vertical velocity component (V_y) is represented by the simplified diagrams in the right column, in which the red arrows symbolize the V_y vectors, pointing toward or away from the bifurcation region. The blue symbols represent the resulting fluid motion in the perpendicular direction, namely the V_⊥ vectors, pointing outward (circle with a dot in the middle) or inward (circle with a cross in the middle). The average velocity components parallel and perpendicular to the plate (V_// and V_⊥) are indicated in millimeters per second. They are noted Ave_BI or Ave_PI depending on the averaging surface (BI region or PI region), and the difference between the averages Δ(Ave_BI – Ave_PI) is also shown.