Journal of Turbulence 

About: Journal of Turbulence is an academic journal published by Taylor & Francis. The journal publishes majorly in the area(s): Turbulence & Reynolds number. It has an ISSN identifier of 1468-5248. Over the lifetime, 1026 publications have been published receiving 27986 citations. The journal is also known as: JoT.

On coherent-vortex identification in turbulence

Abstract: The identification issue of coherent vortices is investigated on the basis of direct numerical simulation (DNS) and large-eddy simulations (LES) of turbulent flows. It is first shown that the pressure Laplacian is positive within a low-pressure tube of small cross section enclosed by convex isobaric surfaces in a uniform-density flow. Since this quantity is related to the second invariant Q of ∇ u , the Q criterion (region where Q is positive) is a necessary condition for the existence of such tubes. This eduction scheme is compared to other classical methods in incompressible simulations of isotropic turbulence: a mixing layer, a channel flow and a backward-facing step. Q-isosurfaces turn out to display very nice coherent vortices. This criterion is also used in combination with a conditional sampling method to discuss the characteristics of quasi-longitudinal vortices in a manipulated channel flow. The contribution of near-wall vortical structures to velocity and vorticity fluctuations is clearly isolat...

A public turbulence database cluster and applications to study Lagrangian evolution of velocity increments in turbulence

Abstract: A public database system archiving a direct numerical simulation (DNS) data set of isotropic, forced turbulence is described in this paper. The data set consists of the DNS output on 10243 spatial points and 1024 time samples spanning about one large-scale turnover time. This complete 10244 spacetime history of turbulence is accessible to users remotely through an interface that is based on the Web-services model. Users may write and execute analysis programs on their host computers, while the programs make subroutine-like calls that request desired parts of the data over the network. The users are thus able to perform numerical experiments by accessing the 27 terabytes (TB) of DNS data using regular platforms such as laptops. The architecture of the database is explained, as are some of the locally defined functions, such as differentiation and interpolation. Test calculations are performed to illustrate the usage of the system and to verify the accuracy of the methods. The database is then used to analy...

A numerical study of the effects of atmospheric and wake turbulence on wind turbine dynamics

Abstract: Although the atmospheric sciences community has been studying the effects of atmospheric stability and surface roughness on the planetary boundary layer for some time, their effects on wind turbine dynamics have not been well studied. In this study, we performed numerical experiments to explore some of the effects of atmospheric stability and surface roughness on wind turbine dynamics. We used large-eddy simulation to create atmospheric winds and compute the wind turbine flows, and we modeled the wind turbines as revolving and flexible actuator lines coupled to a wind turbine structural and system dynamic model. We examined the structural moments about the wind turbine blade, low-speed shaft, and nacelle; power production; and wake evolution when large 5-MW turbines are subjected to winds generated from low- and high-surface roughness levels representative of offshore and onshore conditions, respectively, and also neutral and unstable atmospheric conditions. In addition, we placed a second turbine 7 rotor...

Large eddy simulation and experimental study of flashback and blow-off in a lean partially premixed swirled burner

Abstract: Lean premixed prevaporized (LPP) combustion is a widely used concept for reducing pollutant emissions ingas turbines. In LPP systems, a mixing tube is added between the injector and the combustion chamber to promote mixing and combustion eff

Turbulent structures in accelerating boundary layers

Abstract: The vortical structures in spatially developing turbulent boundary layers subjected to streamwise acceleration are studied. Two cases are examined: one in which the acceleration is insufficient to cause reversion to the laminar state of the initially turbulent flow, and another in which the acceleration is stronger and relaminarization begins to take place; the pressure gradient, however, is not maintained long enough for full reversion to occur. The turbulent statistics show the expected trends: the mean velocity profile deviates significantly from the logarithmic law-of-the-wall and shows, in the strongly accelerated case, a tendency to approach the laminar profile; the turbulent kinetic energy increases less rapidly than the energy of the mean flow. The structure of the inner layer is also significantly altered. In the near-wall region, the streaks become more elongated and show fewer undulations, owing to a significant decrease of the spanwise fluctuations relative to the streamwise ones. The coherent...