Enhanced Oxygen Transport In Fish Gills – Flow Measurements In A Model

Fish are able to extract oxygen from water effectively and with low energy consumption. In order to understand this trait, we investigated the fl ow in a fi sh gill model. We performed particle image velocimetry measurements on an enlarged simplifi ed model of a fi sh gill. Two fl uid models were used in the experiments: a one-phase and a two-phase fl ow, the latter of which models blood fl ow. The local hematocrit value distribution was investigated for the two-phase fl ow. In addition, the fl ow was visualized by dye injection for both fl uid models. It was concluded from the results that the effective gas exchange is due to an enhanced transversal exchange within the gill with a two-phase fl ow, a deformation of the erythrocytes, and a local increase in hematocrit.