scholarly journals Role of barriers in the airborne spread of virus-containing droplets: A study based on high-resolution direct numerical simulations

2022 ◽  
Vol 34 (1) ◽  
pp. 015104
Author(s):  
M. Cavaiola ◽  
S. Olivieri ◽  
J. Guerrero ◽  
A. Mazzino ◽  
M. E. Rosti
Keyword(s):  
High Resolution ◽  
Numerical Simulations ◽  
Direct Numerical Simulations

scholarly journals Shear Driven Turbulence and Coherent Structures in Solar Surface Simulations

2008 ◽  
Vol 4 (S252) ◽  
pp. 451-461 ◽  
Author(s):  
F. Kupka
Keyword(s):  
High Resolution ◽  
Boundary Conditions ◽  
Numerical Simulations ◽  
Observational Data ◽  
Coherent Structures ◽  
Solar Surface ◽  
Large Set ◽  
Mode Excitation

AbstractNumerical simulations of convection near the solar surface are now advanced enough to reproduce both a large set of observational data and provide tests for convection models. We discuss the role of coherent structures in models of solar p-mode excitation, for which the analysis of numerical simulations has provided key inputs in the modelling. The robustness of these simulations is shown by a comparison illustrating the influence of boundary conditions on ensemble averaged quantities. In a concluding example advanced high resolution simulations are shown to resolve the onset of shear driven turbulence generated by up- and downflow structures.

scholarly journals Lift enhancement by bats' dynamically changing wingspan

2015 ◽  
Vol 12 (113) ◽  
pp. 20150821 ◽  
Author(s):  
Shizhao Wang ◽  
Xing Zhang ◽  
Guowei He ◽  
Tianshu Liu
Keyword(s):  
Numerical Simulations ◽  
Nonlinear Interaction ◽  
Mechanical Energy ◽  
Leading Edge ◽  
Direct Numerical Simulations ◽  
Flow Structures ◽  
Vortical Structures ◽  
Geometrical Effect ◽  
Lift Enhancement

This paper elucidates the aerodynamic role of the dynamically changing wingspan in bat flight. Based on direct numerical simulations of the flow over a slow-flying bat, it is found that the dynamically changing wingspan can significantly enhance the lift. Further, an analysis of flow structures and lift decomposition reveal that the elevated vortex lift associated with the leading-edge vortices intensified by the dynamically changing wingspan considerably contributed to enhancement of the time-averaged lift. The nonlinear interaction between the dynamically changing wing and the vortical structures plays an important role in the lift enhancement of a flying bat in addition to the geometrical effect of changing the lifting-surface area in a flapping cycle. In addition, the dynamically changing wingspan leads to the higher efficiency in terms of generating lift for a given amount of the mechanical energy consumed in flight.

scholarly journals The turbulent response to tidal and libration forcing

2019 ◽  
Vol 82 ◽  
pp. 51-58
Author(s):  
B. Favier ◽  
A. Grannan ◽  
T. Le Reun ◽  
J. Aurnou ◽  
M. Le Bars
Keyword(s):  
High Resolution ◽  
Numerical Simulations ◽  
Zonal Flow ◽  
Velocity Measurements ◽  
Solutal Convection ◽  
Tidal Forcing ◽  
Developed Turbulence ◽  
Elliptical Instability

In conjunction with thermo-solutal convection, the turbulence generated in planetary liquid cores may be due to the role of boundary forcing through geophysically relevant mechanisms such as precession, libration and tidal forcing (Le Bars et al. 2015). In this paper, we discuss laboratory equatorial velocity measurements and selected high-resolution numerical simulations to show the generation of developed turbulence driven by longitudinal libration or tidal forcing. In both cases, the transition to saturated turbulence is driven by an elliptical instability that excites inertial modes of the system. We find striking similarities in both the transition to bulk turbulence and the enhanced zonal flow hinting at a generic fluid response independent of the forcing mechanism. We finally discuss the relevance of this work to the planetary regime and possible directions for future investigations.

Energy dissipation rate and energy spectrum in high resolution direct numerical simulations of turbulence in a periodic box

2003 ◽  
Vol 15 (2) ◽  
pp. L21-L24 ◽  
Author(s):  
Yukio Kaneda ◽  
Takashi Ishihara ◽  
Mitsuo Yokokawa ◽  
Ken’ichi Itakura ◽  
Atsuya Uno
Keyword(s):  
Energy Spectrum ◽  
Energy Dissipation ◽  
High Resolution ◽  
Numerical Simulations ◽  
Dissipation Rate ◽  
Energy Dissipation Rate ◽  
Direct Numerical Simulations
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