Turbulent flow over liquid-infused superhydrophobic surfaces: An experimental investigation into the drag performance and flow mechanics

Surfaces that induce slip at the wall have been shown to reduce skin friction drag in the turbulent regime. While superhydrophobic and liquid-infused surfaces are capable of drag reduction in turbulent hydrodynamic flows, neither would be feasible in aerodynamic applications due to the added roughness and the minuscule slip lengths created by...

Chevron-shaped protrusions for turbulent drag reduction: Experimental investigation into the drag performance and flow mechanics

In the last decades, the prevailing belief that smooth surfaces offer the lowest drag has been challenged often. Scholars have, for example, introduced rough and modified surfaces to reduce turbulent skin friction. One of the technologies proposed in the literature is an array of chevron-shaped protrusions; however, there is no academic...

Turbulent boundary layers over surfaces with streamwise-preferential permeability: Experimental investigation into the drag and flow mechanics

Turbulent drag is the largest source of fuel consumption in aviation and forms a significant contribution to climate warming. Recent numerical studies have suggested the ability of surfaces with streamwise-preferential permeability to reduce turbulent friction, and a theoretical framework behind the working mechanism has been proposed. This work...

Numerical investigation of the turbulent boundary layer over dimpled surfaces

Dimples are shallow, indented surfaces that attempt to reduce drag in turbulent boundary layer flows. However, the underlying effect of the dimples on the drag is not entirely understood. This thesis sets out to expand our understanding; a numerical investigation of turbulent boundary layer flow over dimpled surfaces is conducted. This research...

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...

Going against the flow: An experimental investigation into the flow mechanics of dimpled surfaces in turbulent boundary layers

Any reduction in vehicle drag or fluid resistance provides a potential of substantial energy savings, with obvious benefits to the economy, environment and overall industrial competitiveness. Although various experimental studies have confirmed the potential drag reduction of dimpled surfaces in a turbulent boundary layer (BL), the working...