Article 4
Hydrodynamic Drag of O. niloticus and C. batrachus
by Lapatrada Damkong, Poon Veerarittiphan, Sirada Indee, Thiti Suteesopon
Abstract
The effect of fish physiology on hydrodynamics is investigated by comparing the drag coefficients of Oreochromis niloticus, which is characterized by a flat body with scales, and Clarias batrachus, which is characterized by a long, rounded body with smooth skin. The fish were towed horizontally through water using a pulley system, and their velocity was tracked. Reynolds numbers were calculated to identify the flow regime. Drag coefficients of O. niloticus and C. batrachus were measured as 0.060 ± 0.007 and 0.042 ± 0.006, respectively, with Reynolds numbers of 1.79 x 10^5 and 2.23 x 10^5. The results indicate that the round, scaleless body of the catfish generates less drag compared to the flat, scaled body of the tilapia.