Transonic Dimples: An experimental study of the flow structures formed at transonic speeds over dimpled surfaces

Dimples are shallow surface indentations that have been recently considered as a passive viscous drag reducing technique for turbulent boundary layers. Studies so far were limited to incompressible low-Re flows and display little consensus on whether dimples can actually produce net improvements in total drag. Conversely, dimple geometry can be...

On the turbulent drag reduction of a dimpled surface under a pressure gradient

Dimples are spherical indentations applied at a surface that have been found to yield a skin-friction drag reduction within a turbulent boundary layer. Shallow dimples have inherent advantages over traditional flow control techniques that require heavy active systems to be installed or pose maintenance problems. Proven drag-reducing mechanisms...