Evaluation and selection of optimal geometric parameters of rectangular riblets for hydraulic loss reduction

Based on Computational Fluid Dynamics simulations performed in ANSYS Fluent, the geometric parameters of rectangular riblets were evaluated to assess their impact on hydraulic loss reduction in pipe flow. The study investigated riblet height h (1.0, 1.2, 1.4, and 1.6 mm) and the height-to-thickness ratio h/t (1.0, 1.1, 1.2, 1.4, and 1.6) at a fixed height-to-spacing ratio of h/s = 0.4. The results indicate that the best hydraulic efficiency is achieved at a height of 1 mm. Furthermore, at a ratio of h/t = 1,1, rectangular riblets (0,0259) provide a 2.6% reduction in hydraulic resistance compared to an ideally smooth surface (0,0266).
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