coherent structures in large
The large-scale coherent structures comprise the one-cell and two-cell flow patterns. We found that a main contribution to the turbulence kinetic-energy production in turbulent convection with large-scale coherent structures is due to the nonuniform large-scale motions.
Jun 01, 2013 · Although the generation mechanism of the large-scale coherent structures has not been clarified, it is clear that they play an important role in momentum transport (Guala et al. 2006) and affect velocity and scalar fields below them (Marusic et al. 2010; Inagaki et al. 2012). Abstract - EprintsWe will call coherent structures large if their extent, in at least one dimension, is of the order of or larger than a characteristic length-scale, say the body height or the shear-layer thickness.
Aug 23, 2019 · We study large-eddy simulations of coherent structures within and above different wind-farm configurations in a neutral atmospheric boundary layer (ABL) using proper orthogonal decomposition (POD) to improve understanding of the flow structures in both physical and spectral space. We find that the spanwise extent of elongated streamwise counter-rotating rolls is constrained by the spanwise Detecting Coherent Structures in Large-Eddy Simulation of Dec 01, 2015 · Coherent structures such as the vortical updrafts (and their shell) and subsidence are the main heat- and moisture-transporting flow structures in atmospheric convective layers. Although understanding their stochastic characteristics is essential in improving convection parameterization, even detecting them in well simulated numerical data is difficult because of their complex spatial and
Jan 20, 2021 · that the large-scale motion (LSM) of three-dimensional coherent structures resides within the buffer and the logarithmic layer . From this resulted an early classication of coherent structures, which were limited to wall-bounded low Reynolds number ows, i.e., a scale of size O(d), where d is the boundary layer thickness . LARGE-SCALE COHERENT TURBULENCE STRUCTURES INLarge-scale organized structures have an impor-tant role in mixing layer growth and may promote unsteadiness in shock wave / shear layer interac-tions . The goals of the project described in this paper were to characterize these coherent structures using quantitative measures derived from ow vi-sualization data. The length scale
The relative merits of each technique are considered, followed by an analysis of the extracted coherent structures and of their contribution to the flow dynamics. It is shown that the large scale coherent structures play a significant role in the observed dissimilarity between heat and momentum transfer in the disturbed boundary layer. Large-scale coherent structures in compressible The presence of large-scale coherent structures in various wall bounded turbulent ows, often called superstructures in turbulent boundary layers (TBLs), has been of great interest in recent years. These meandering high- and low-momentum structures can extend up to several boundary layer thicknesses in the streamwise direction and contain
Abstract. Large-scale coherent motions in the atmospheric boundary layer are investigated from eld measurements made with two scanning wind lidars over a two-dimensional domain covering approximately 50km2. The size, isotropy and two-point statistics of the coherent structures, show their in uence on wind eld homogeneity and local conditions Nonlinearity INVITED ARTICLE Related content Small Small scale exact coherent structures at large Reynolds numbers in plane Couette flow Bruno Eckhardt1 and Stefan Zammert2 1 Fachbereich Physik, Philipps-Universtät Marburg, Renthof 6, 35032 Marburg, Germany 2 Laboratory for Aero and Hydrodynamics, TU Delft, 2682 Delft, The Netherlands E-mail:[email protected]
Under consideration for publication in J. Fluid Mech. 1 On coherent structure in wall turbulence A. S. SHARMA1 AND B. J. McKEON2 1Aerodynamics and Flight Mechanics, Faculty of Engineering and the Environment, University of Southampton, SO17 1BJ, UK 2Graduate Aerospace Laboratories, California Institute of Technology, Pasadena, CA 91125, USA (Received 16 July 2012; revised 23 May 2013; Published online 24 August 2011 Emergence of coherent The emergence of coherent structures, large-scale ows and correlated dynamics in suspensions of motile particles such as swimming micro-organisms or articial microswimmers is studied using direct particle simulations.
title = "Streaks and coherent structures in jets from round and serrated nozzles", abstract = "Hydrodynamic instabilities are directly related to large-scale coherent structures that are correlated with jet noise emission. Unravelling and accurately predicting their fundamental dynamics shows a promising direction for designing quieter jet engines. The dynamics of coherent structures in the wall region of here is therefore limited in application to certain types of flows in which large coherent structures contain a major fraction of the energy. It has been demonstrated that axisymmetric turbulent jet mixing layers (Glauser, Leib & George 1985a) and wall regions of turbulent boundary layers (Moin 1984; Herzog 1986) belong to this group.
structures that are coherent over large wall-normal distances and that are self-similar. We nd that, with the addition of an eddy viscosity pro le, these features of the large-scale structures are captured by the linearized equations, except in the region close to the wall. To further study this coherence, a coherence-based estimation technique