Abstract: A transition model based on unstructured mesh was applied for simulation of the model and full scale propeller with varied Reynolds number (Re) on the commercial software STAR-CCM+platform. Changes of boundary-layer flow over blade face and blade back with Re were studied. Numerical results of friction coefficient of the 0.75R blade section were compared with those calculated by the ITTC formulas and the plate resistance formulas. The scaling method recommended by ITTC was improved at low Reynolds number range that two formulas were proposed for calculating viscous force coefficients of propeller blade face and blade back separately. Results show that the boundary-layer flow over blade face and blade back are different. Thus, different equations were needed to calculate the friction coefficients of suction side and pressure side of the blade section. Results show that when Re is small (close to the critical Re), results of the revised method are better than those of the ITTC method; when Re is greater than 1.0×106, results by the two methods are basically the same; when Re continues to increase (greater than 2.0×106), results calculated by the two methods both deviate from the actual value with the increase of Re.

Key words: marine propeller, propulsion performance, Reynolds number, transition flow, scale effects