scholarly journals Lagrangian coherent structures and material transport in unsteady flow of vertical-axis turbine wakes

AIP Advances ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 085001
Author(s):  
Kun Wang ◽  
Li Zou ◽  
Jiuming Zhang ◽  
Yichen Jiang ◽  
Peidong Zhao
Keyword(s):  
Unsteady Flow ◽  
Coherent Structures ◽  
Vertical Axis ◽  
Lagrangian Coherent Structures ◽  
Material Transport ◽  
Vertical Axis Turbine

Lower thermospheric material transport via Lagrangian coherent structures

2021 ◽  
Author(s):  
S. Datta‐Barua ◽  
N. Pedatella ◽  
K. R. Greer ◽  
N. Wang ◽  
L. Nutter ◽  
...  
Keyword(s):  
Coherent Structures ◽  
Lagrangian Coherent Structures ◽  
Material Transport

scholarly journals Pollution Transport Patterns Obtained Through Generalized Lagrangian Coherent Structures

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 168
Author(s):  
Peter J. Nolan ◽  
Hosein Foroutan ◽  
Shane D. Ross
Keyword(s):  
Velocity Field ◽  
Coherent Structures ◽  
Initial Conditions ◽  
Saddle Points ◽  
Chemical Species ◽  
Lagrangian Coherent Structures ◽  
Time Interval ◽  
Pollution Transport ◽  
Material Transport ◽  
Material Surfaces

Identifying atmospheric transport pathways is important to understand the effects of pollutants on weather, climate, and human health. The atmospheric wind field is variable in space and time and contains complex patterns due to turbulent mixing. In such a highly unsteady flow field, it can be challenging to predict material transport over a finite-time interval. Particle trajectories are often used to study how pollutants evolve in the atmosphere. Nevertheless, individual trajectories are sensitive to their initial conditions. Lagrangian Coherent Structures (LCSs) have been shown to form the template of fluid parcel motion in a fluid flow. LCSs can be characterized by special material surfaces that organize the parcel motion into ordered patterns. These key material surfaces form the core of fluid deformation patterns, such as saddle points, tangles, filaments, barriers, and pathways. Traditionally, the study of LCSs has looked at coherent structures derived from integrating the wind velocity field. It has been assumed that particles in the atmosphere will generally evolve with the wind. Recent work has begun to look at the motion of chemical species, such as water vapor, within atmospheric flows. By calculating the flux associated with each species, a new effective flux-based velocity field can be obtained for each species. This work analyzes generalized species-weighted coherent structures associated with various chemical species to find their patterns and pathways in the atmosphere, providing a new tool and language for the assessment of pollutant transport and patterns.

scholarly journals Unsteady flow around a two-dimensional section of a vertical axis turbine for tidal stream energy conversion

2009 ◽  
Vol 1 (2) ◽  
Author(s):  
Hyun Ju Jung ◽  
Ju Hyun Lee ◽  
Shin Hyung Rliee ◽  
Museok Song ◽  
Beom-Soo Hyun
Keyword(s):  
Unsteady Flow ◽  
Energy Conversion ◽  
Stokes Equations ◽  
Vertical Axis ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Tidal Stream ◽  
Tidal Stream Energy ◽  
Vertical Axis Turbine

ABSTRACTThe two-dimensional unsteady flow around a vertical axis turbine for tidal stream energy' conversion was investigated using a computational fluid dynamics tool solving the Reynolds-Averaged Navier-Stokes equations. The geometry' of the turbine blade section was NACA653-01S airfoil. The computational analysis was done at several different angles of attack and the results were compared with the corresponding experimental data for validation and calibration. Simulations were then carried out for the two-dimensional cross section of a vertical axis turbine. The simulation results demonstrated the usefulness of the method for the typical unsteady flows around vertical axis turbines. The optimum turbine efficiency was achieved for carefully selected combinations of the number of blades and tip speed ratios.

Persistency of debris accumulation in tidal estuaries using Lagrangian coherent structures

2021 ◽  
pp. 146808
Author(s):  
Anusmriti Ghosh ◽  
Kabir Suara ◽  
Scott W. McCue ◽  
Yingying Yu ◽  
Tarmo Soomere ◽  
...  
Keyword(s):  
Coherent Structures ◽  
Lagrangian Coherent Structures ◽  
Debris Accumulation ◽  
Tidal Estuaries

Lagrangian coherent structures deduced from HF radar measurements

2015 ◽  
Author(s):  
Francesco Enrile ◽  
Giovanni Besio ◽  
Marcello G. Magaldi ◽  
Carlo Mantovani ◽  
Simone Cosoli ◽  
...  
Keyword(s):  
Coherent Structures ◽  
Hf Radar ◽  
Lagrangian Coherent Structures ◽  
Radar Measurements
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