INTERACTION DYNAMICS OF STRUCTURED SURFACE PATTERN FOR VISCOUS DRAG REDUCTION

Abstract

Subduing turbulence with the objective of reducing viscous drag experienced by body moving in fluids has been an active area of research. Previous research has demonstrated the potential of structured surfaces in reducing the turbulent viscous drag. However, the manner in which the interaction of these surfaces with the unsteady and complex turbulent flow can yield a benign effect on viscous drag is still inconclusive. The present dissertation intends to investigate the interaction of a structured surface known as riblets with the overlying flow. Specifically, this study aims to investigate the role of riblet geometry in tuning the flow control effectiveness, and the ensuing drag reduction capability. The objectives are accomplished by considering the near-wall flow statistics, structures, topologies, and by identifying the relations or ramifications of modifying these aspects on the turbulence processes. Following that, an investigation of the interaction of riblets with well-defined longitudinal vortex structures is performed.