Advancing the Flow Physics Behind the Drag of Riblets

PIV measurements within roughness grooves with enhanced wall reflection suppression

W Abu Rowin, P Manovski, D Chung, N Hutchins

2025-01-01

Wall reflection of laser light in particle image velocimetry (PIV) measurements is one of the limiting factors in obtaining veloci..

Why do only some riblets promote spanwise rollers?

CJ Camobreco, S Endrikat, R García-Mayoral, M Luhar, D Chung

2025-01-01

Linear-stability modelling suggests that all sufficiently large riblets promote maximally growing spanwise rollers (García-Mayoral..

Effects of roughness on non-equilibrium turbulent boundary layers

Ralph J Volino, Daniel Fritsch, William J Devenport, Luis Eca, Ricardo Garcia-Mayoral, Beverley Mckeon, Ugo Piomelli, Daniel Chung, Vidya Vishwanathan, Maarten Kerkvliet, Serge Toxopeus, Nicholas Hutchins

2024-11-01

The effects of roughness were considered as part of a NATO Advanced Vehicle Technology effort titled ‘Non-Equilibrium Turbulent Bo..

A viscous vortex model for predicting the drag reduction of riblet surfaces

J Wong, CJ Camobreco, R García-Mayoral, N Hutchins, D Chung

2024-01-10

This paper introduces a viscous vortex model for predicting the optimal drag reduction of riblet surfaces, eliminating the need fo..

Challenges and perspective on the modelling of high-Re, incompressible, non-equilibrium, rough-wall boundary layers

R García-Mayoral, D Chung, P Durbin, N Hutchins, T Knopp, BJ McKeon, U Piomelli, RD Sandberg

2024-01-01

The present paper gives an overview of the recent modelling activities under NATO-STO AVT-349, focussed on the understanding and m..

Reorganisation of turbulence by large and spanwise-varying riblets

S Endrikat, R Newton, D Modesti, R García-Mayoral, N Hutchins, D Chung

2022-12-10

We study the flow above non-optimal riblets, specifically large drag-increasing and two-scale trapezoidal riblets. In order to rea..

Important Parameters for a Predictive Model of ks for Zero-Pressure-Gradient Flows

Karen A Flack, Daniel Chung

2022-10-01

To predict drag on a rough surface under turbulent flow conditions, practitioners rely on roughness correlations that map topograp..