Pengaruh permukaan hydrophobic pada aliran turbulen dalam pipa akan diteliti. Penelitian ini menggunakan air sebagai fluida serta tiga jenis daun talas, yaitu Colocasia gigantea, Colocasia esculenta, dan Colocasia fontanesii. Tiga pipa akrilik 7 × 7 mm, masing-masing dinding dalam pipa tersebut dilapisi dengan ketiga jenis daun talas tersebut. Drag reduction terbesar yang dihasilkan oleh dinding daun Colocasia gigantea yaitu sebesar 22,6% pada Re 7300 dengan ratarata DR sebesar 16,3%, sedangkan drag reduction terbesar yang dihasilkan dinding daun Colocasia esculenta dan dinding daun Colocasia fontanesii masingmasing sebesar 15,3% dan 20,5% pada Re 6400 dengan rata-rata DR masingmasing sebesar 12,6% dan 12,5%.

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The effect of hydrophobic surfaces on turbulent flow in a pipe were investigated. This study used water as the fluid and three types of leaves of taro, Colocasia gigantea, colocasia esculantea, and colocasia fontanesii. Three acrylic pipes were coated the three types of taro leaves. Reynolds number and characteristics of the pressure drop is the main variable to be studied. Rectangular pipes 7 x 7 mm those coated with the leaves showed a reduction in coefficient of friction. The biggest drag reduction produced by the leaf of Colocasia gigantea wall is equal to 22,6% at Re 7300 with an average DR 16.35%, while the largest drag reduction produced by Colocasia esculantea leaf and Colocasia fontanesii leaf are 15,3% and 20,5% at Re 6400 with average DR 12,6% and 12,5%.