Top view of velocity vector fields at three heights inside the P. meandrina colony.

The vector fields were obtained at heights z = 0.3H (left), 0.5H (top right), and 0.7H (bottom right) above the base of the coral colony, where H is the colony height. The figures show higher velocity magnitudes at the anterior end of the colony and allow one to gauge how far the oncoming flow can penetrate easily into the colony before it is slowed substantially by frictive contact with the coral branches.