Turbulent Drag Reduction Using Compliant Coatings

摘要

The skin-friction drag of compliant coatings was measured using an axi-symmetric test model in a water tunnel for flow speed up to 4.5 m/s at the Reynolds number of 2.3 million. There were measurable drag reductions for up to 3% from three out of five compliant coatings tested. Only one coating showed a small drag increase, and the other had no change in drag. For all the tests, the 95% confidence level in measured drag reduction was 1% for flow velocities between 2.5 and 4.5 m/s. The error analysis suggested that the uncertainty was progressively increased with a reduction in flow velocity.