INVESTIGATION OF TURBULENT ATMOSPHERIC FLOW MODIFIED BY ARTIFICIAL AND NATURAL POROUS BARRIERS APPLIED TO CONTROL THE WIND EROSION OF GRANULATED MATERIALS

Name: Jamily Faé Stocco
Type: MSc dissertation
Publication date: 17/08/2021
Advisor:

Namesort descending Role
Jane Meri Santos Advisor *

Examining board:

Namesort descending Role
Acir Mércio Loredo-Souza External Examiner *
Bruno Furieri Co advisor *
Elisa Valentim Goulart Internal Examiner *
Jane Meri Santos Advisor *
Rafael Sartim External Examiner *

Summary: The emission of particulate matter and its transport into the atmosphere result in increased
concentrations of particles in the atmosphere, causing degradation of air quality and
potential generation of risks to human health. The presence of wind barriers around
industrial yards of granular materials storage piles is an important method of controlling
these fugitive emissions by reducing the near surface wind velocity. Such importance in
erosion control motivated the present work, which aims to study turbulent atmospheric
flow in the presence of natural and artificial barriers, in order to analyze its influence in
reducing the flow velocity and the shelter region due to its presence. Numerical
simulations of atmospheric flow through wind barriers were performed using different
mathematical modeling setup, in addition to different RANS turbulence models. The
results were compared to data from wind tunnel experiments found in the literature to
validate the numerical simulations. The sensitivity of the velocity field in relation to the
morphological parameters of plant barriers and the porosity of artificial barriers was
investigated. The models showed better flow prediction in the inner region of the barrier,
and had less precision in predicting the wake results for all scenarios (underestimation of
the dimensionless coefficient of velocity reduction). The behavior of the RANS
turbulence models was very similar with differences of around 12% for medium and high
densities and 34% for low density of trees in the barrier. The use of the vertical profile of
the inertial resistance coefficient for the natural barrier improved the flow prediction
within the tree barrier, influenced the formation of the shelter region and the friction
velocity in the downstream region. Additionally, the porosity parameter of the artificial
barrier played an important role in reducing the friction speed for these cases. The
increase in porosity led to a milder reduction in the friction velocity in the protection
region downstream of the barrier, which was 32% lower when the porosity increased to
60%, but increased the protection area due to the barrier. With the present work it was
possible to understand in detail the flow modified by porous barriers to attenuate the wind
velocity and to identify best practices of mathematical modeling of porous barriers with
a view to application in complete studies involving the erosion of granular materials
storage piles and roads in industrial yards.

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