Net drag effect of dimples on flat or weakly curved surfaces

Determine whether dimpled flat or weakly curved aerodynamic surfaces can produce a net drag reduction across varying dimple shapes and configurations, given the competing skin-friction and pressure-drag effects.

Background

The paper frames the aerodynamic effectiveness of dimples as dependent on a complex interaction between surface geometry and near-wall flow. On flat or weakly curved surfaces, dimples can alter both skin-friction drag and pressure drag through changes in near-wall vorticity, flow separation, and Reynolds-stress production.

The authors note that prior studies have reported conflicting outcomes, including both drag reduction and drag increase, depending on dimple shape and configuration. The present study addresses this uncertainty for a specified turbulent channel-flow setting and design space, but the broader question of whether dimples can reliably provide a net benefit across flat or weakly curved aerodynamic surfaces remains unresolved.