Showing papers in "Fluid Dynamics Research in 2019"

TL;DR: In this article, different spectral filters (temporal, spatial, or both) and empirical mode decomposition (EMD) are evaluated and compared for scale decomposition in wall-bounded turbulent flows.

TL;DR: In this paper, the authors argue that the main effect of these surfaces can be expressed as an offset between the positions of the virtual, equivalent smooth walls perceived by different parts of the flow, namely by the mean velocity profile and by the background turbulence.

TL;DR: In this paper, a resolvent analysis of exact coherent states (ECS) of the Navier-Stokes equations (NSE) in a low Reynolds number channel is performed, where the nonlinear term is treated as an internal forcing that drives the linear dynamics of the system.

TL;DR: The Rayleigh-Taylor instability develops when fluids are accelerated counter to their density gradients; intense interfacial fluid mixing ensues with time as discussed by the authors, and it is shown that Rayleigh Taylor mixing may exhibit order and laminarize, similarly to other accelerated flows.

TL;DR: In the quasilinear approximation to the Navier-Stokes equation, a minimal set of nonlinearities that are able to maintain turbulent dynamics is kept.

TL;DR: In this article, smoke image velocimetry (SIV) measurements of instantaneous two-dimensional velocity vector fields in complex turbulent flows with high spatial resolution of the order of Kolmogorov scale were obtained.

TL;DR: The hierarchical random additive process (HRAP) model as mentioned in this paper models the near-wall momentum-carrying parts of turbulence by exploiting the self-similarity and the tree-like hierarchical organization of attached eddies.

TL;DR: In this paper, the authors investigated the binary droplet collisions with large density ratios (DR) via an improved pseudopotential multiple-relaxation-time (MRT) Lattice Boltzmann Method (LBM) model.

TL;DR: In this article, the authors investigate the relationship between the extent of a localized structure and its lifetime and show that the lifetime of turbulent "puffs" increases double-exponentially as a function of the Reynolds number for any spanwise extent.

TL;DR: In this article, a simple and new empirical method for determining the friction velocity in zero pressure gradient turbulent boundary layers is presented, which relies on the collapse of the streamwise mean velocity defect profiles of the boundary layers over smooth and rough walls when normalised by the friction velocities.

TL;DR: In this article, the authors discuss the assessment of getting self-sustained large oscillation amplitudes of multiple FVGs from an upstream confined laminar flow and show that a minimum of three alternating FVG generators is needed to produce a self-sufficient and periodic flow instability, leading to large FVG displacement.

TL;DR: In this article, the aerodynamic properties of two tandem square cylinders were investigated in horizontal and diagonal arrangement respectively, with the variation of the spacing ratio (i.e., the center-to-center space P versus the width B of the square cylinder) P/B = 1.75 ~ 5 at Re = 8×104 in the present study.

TL;DR: In this paper, a flexible splitter plate made of a plastic material was easily deformed under the influence of vortical flow, and the presence of a flexible flow control element located along the central axis line of the cylinder significantly affects the vortex formations.

TL;DR: In this paper, two time-periodic flows embedded in Large Eddy Simulation (LES) of turbulence in a three-dimensional, periodic domain subject to constant external forcing are described and compared.

TL;DR: Tanaka as mentioned in this paper performed a fully resolved simulation on the motion of spherical bubbles in homogeneous turbulence subject to a vertical flow that is uniformly sheared in a horizontal direction in order to understand the effect of turbulence on the transverse migration of rising bubbles.