We study turbulent channel flow of an electrically conducting liquid with a homogeneous magnetic field imposed in the spanwise direction. The Lorentz force is modelled using the quasistatic approximation. Direct and large-eddy simulations are performed for hydrodynamic Reynolds numbers Re=10000 and Re=20000 and the Hartmann number varying in a wide range. The main effect of the magnetic field i...

This paper extends the study by Tee et al. (2020) to investigate effect of large coherent structures on motion spheres with specific gravities 1.006 (P1) and 1.152 (P3) at Reτ = 670 1300 (d+ 56 116). The sphere fluid motions are tracked simultaneously via 3D particle tracking stereoscopic image velocimetry over streamwise-spanwise plane, respectively. With sufficient mean shear, P1 lifts off wa...

During the last few years, a number of numerical boundary condition schemes have been used to study various aspects of the no-slip wall condition using the lattice Boltzmann method. In this paper, a modified boundary condition method is employed to simulate the no-slip wall condition in the presence of the body force term near the wall. These conditions are based on the idea of the bounce-back ...

Effects of hydrophobic surface on skin-friction drag are investigated through direct numerical simulations of a turbulent channel flow. Hydrophobic surface is represented by a slip-boundary condition on the surface. When a slip-boundary condition is used in the streamwise direction, the skin-friction drag decreases and turbulence intensities and turbulence structures, near-wall streamwise vorti...

Synchronization of turbulence in channel flow is investigated using continuous data assimilation. The unknown within a region the channel. Beyond this velocity field provided, and directly prescribed simulation, while pressure throughout entire domain. takes place when simulation recovers full true state flow, or other words missing accurately re-established, spontaneously. Successful synchroni...

Opposition flow control is a robust strategy that has been proved effective in turbulent wall-bounded flows. Its conventional set-up consists of measuring wall-normal velocity the buffer layer and opposing it at wall. This work explores possibility implementing this with detection plane logarithmic layer, where could be feasible experimentally. We apply on channel $Re_\tau = 932$ , only eddies ...

A synthetic spanwise-constant spatio-temporal mode is excited in a flat plate turbulent boundary layer through a spatially impulsive patch of dynamic wall-roughness. The streamwise wavelength of the synthetic mode approximately corresponds to the very large-scale motions present in high Reynolds number wall turbulence. Hot wire anemometer measurements made downstream of the roughness forcing re...

In this paper an experimental and theoretical investigation is presented on the role of large-scale coherent structures in the zeropressure-gradient turbulent boundary layer. Attention is given to the proposal by Adrian, Meinhart & Tomkins (2000) that hairpin vortices are organized into spatially correlated packets or trains of vortices which extend over many boundary layer thicknesses in the s...