Presenting an analytical relationship for predicting the drag coefficient reduction in the presence of toothed riblets based on effective dimensionless factors.

Reducing the resistance force in order to access more power, higher speed, and less fuel consumption is one of the various goals in scientific research. Considering that the main important problem for a vessel moving in a fluid is the drag force, the tools for reducing drag has attracted the researchers.In this study, the researchers sought to find the mathematical relationship for predict sawtoothed riblets percentage of drag reduction. For this purpose, first, by investigating the result of scientific researches, they are determined the effective variables on drag reduction. Then, by anlyzing the relationship between drag reduction and these variable, fit the curve of the three-dimensional shape of the obtained function, and matching the spatial shape of the relationship with the equations of quadratic procedures, the closest shape that has the ability to match the relationship according to the limits was calculated. it determined elliptic paraboloid relationship. which had a good agreement with the experimental results.