Nicholas Hutchins

Heat-transfer scaling at moderate Prandtl numbers in the fully rough regime

K Zhong, N Hutchins, D Chung

Journal article  |  2023  |  Journal of Fluid Mechanics

In the fully rough regime, proposed models predict a scaling for a roughness heat-transfer coefficient, e.g. the roughness Stanton..

Defining an equivalent homogeneous roughness length for turbulent boundary layers developing over patchy or heterogeneous surfaces

N Hutchins, B Ganapathisubramani, MP Schultz, DI Pullin

Journal article  |  2023  |  Ocean Engineering

A new approach based on the power mean is suggested for defining an equivalent homogeneous roughness length kehr which takes into ..

Reorganisation of turbulence by large and spanwise-varying riblets

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

Journal article  |  2022  |  Journal of Fluid Mechanics

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

Riblet-generated flow mechanisms that lead to local breaking of Reynolds analogy

Amirreza Rouhi, Sebastian Endrikat, Davide Modesti, Richard D Sandberg, Takuo Oda, Koichi Tanimoto, Nicholas Hutchins, Daniel Chung

Journal article  |  2022  |  JOURNAL OF FLUID MECHANICS

We investigate the Reynolds analogy over riblets, namely the analogy between the fractional increase in Stanton number Ch and the ..

Impact of spanwise effective slope upon rough-wall turbulent channel flow

TO Jelly, A Ramani, B Nugroho, N Hutchins, A Busse

Journal article  |  2022  |  JOURNAL OF FLUID MECHANICS

Whereas streamwise effective slope (ESx) is accepted as a key topographical parameter in the context of rough-wall turbulent flows..

Spatiotemporal characteristics of uniform momentum zones: Experiments and modeling

Angeliki Laskari, Charitha M de Silva, Nicholas Hutchins, Beverley J McKeon

Journal article  |  2022  |  PHYSICAL REVIEW FLUIDS

The probability density function (PDF) of the instantaneous streamwise velocity has consistently been used to extract information ..

Modelling the downstream development of a turbulent boundary layer following a step change of roughness

Mogeng Li, Charitha M de Silva, Daniel Chung, Dale Pullin, Ivan Marusic, Nicholas Hutchins

Journal article  |  2022  |  JOURNAL OF FLUID MECHANICS

In this study, we develop an analytical model to predict the turbulent boundary layer downstream of a step-change in the surface r..

Scale-dependent inclination angle of turbulent structures in stratified atmospheric surface layers

Xuebo Li, Nicholas Hutchins, Xiaojing Zheng, Ivan Marusic, Woutijn J Baars

Journal article  |  2022  |  JOURNAL OF FLUID MECHANICS

A large-scale spanwise and wall-normal array of sonic anemometers in the atmospheric surface layer is used to acquire all three co..

The logarithmic variance of streamwise velocity and k(-1) conundrum in wall turbulence

Yongyun Hwang, Nicholas Hutchins, Ivan Marusic

Journal article  |  2022  |  JOURNAL OF FLUID MECHANICS

The logarithmic dependence of streamwise turbulence intensity has been observed repeatedly in recent experimental and direct numer..

Investigation of cold-wire spatial and temporal resolution issues in thermal turbulent boundary layers

Yu Xia, Wagih Abu Rowin, Thomas Jelly, Ivan Marusic, Nicholas Hutchins

Journal article  |  2022  |  INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW

In this study, we use simulations and experiments to investigate spatial and temporal attenuation of cold-wire sensors. A direct n..