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Publication Abstracts Topic Area: Wind Engineering COTech101:
What
scaling means in wind engineering
Abstract.
Wind engineering problems are commonly studied by wind tunnel
experiments at a reduced scale. This introduces several limitations
and calls for a careful planning of the tests and the interpretation
of the experimental results. The talk first revisits the similitude
laws and discusses how they are actually applied in wind engineering.
It will also remind readers why different scaling laws govern in
different wind engineering problems. Secondly, the paper focuses on
the ways to simplify a detailed structure (bridge, building,
platform) when fabricating the downscaled models for the tests. This
will be illustrated by several examples from recent engineering
projects. Finally, under the most severe weather conditions, manmade
structures and equipment should remain operational. What
“recreating the climate” means and aims to achieve will be
illustrated through common practice in climatic wind tunnel
modelling. COTech102:
Implementation
and application of the actuator line model by OpenFOAM for a vertical
axis wind turbine
L
Riva1*,
K-E Giljarhus2,
B Hjertager2
and S M Kalvig2 Abstract.
University
of Stavanger has started The Smart Sustainable Campus & Energy
Lab project, to gain knowledge and facilitate project based education
in the field of renewable and sustainable energy and increase the
research effort in the same area. This project includes the future
installation of a vertical axis wind turbine on the campus roof. A
newly developed Computational Fluid Dynamics (CFD) model by OpenFOAM
have been implemented to study the wind behavior over the building
and the turbine performance. The online available wind turbine model
case from Bachant, Goude and Wosnik from 2016 is used as the starting
point. This is a Reynolds-Averaged Navier-Stokes equations (RANS)
case set up that uses the Actuator Line Model. The available test
case considers a water tank with controlled external parameters.
Bachant et al.’s model has been modified to study a VAWT in the
atmospheric boundary layer. Various simulations have been performed
trying to verify the models use and suitability. Simulation outcomes
help to understand the impact of the surroundings on the turbine as
well as its reaction to parameters changes. The developed model can
be used for wind energy and flow simulations for both onshore and
offshore applications. Keywords.
Vertical axis wind turbine, Computational fluid dynamic, Actuator
line model, Openfoam, Atmospheric boundary layer, Built environment
wind turbine COTech104:3D
WindScanner Lidar Measurements of Wind and Turbulence around Wind
Turbines, Buildings and Bridges Torben
Mikkelsen, Mikael Sjöholm, Nikolas Angelou and Jakob Mann Keywords. 3D Wind field velocity measurements, Atmospheric turbulence, Coherence, dynamic loads application, Suspension bridges, Wind tunnel velocimetry, wind turbines. COTech107:
Aeroelastic
Response from Indicial Functions with a Finite Element Model of a
Suspension Bridge Ove
Mikkelsen
and Jasna B Jakobsen Abstract.
The present paper describes a comprehensive analysis of the
aeroelastic bridge response in time-domain, with a finite element
model of the structure. The main focus is on the analysis of flutter
instability, accounting for the wind forces generated by the bridge
motion, including twisting as well as vertical and horizontal
translation, i.e. all three global degrees of freedom. The solution
is obtained by direct integration of the equations of motion for the
bridge-wind system, with motion-dependent forces approximated from
flutter derivatives in terms of rational functions. For the
streamlined bridge box-girder investigated, the motion dependent wind
forces related to the along-wind response are found to have a limited
influence on the flutter velocity. The flutter mode shapes in the
time-domain and the frequency domain are consistent, and composed of
the three lowest symmetrical vertical modes coupled with the first
torsional symmetric mode. The method applied in this study provides
detailed response estimates and contributes to an increased
understanding of the complex aeroelastic behaviour of long-span
bridges. COTech107:
Wind effects on
long-span bridges: Probabilistic Wind Data Format for Buffeting and
VIV Load Assessments
K Hoffmann1,
R
Ge Srouji1
and S O Hansen1,2 Abstract.
The technology development within the structural design of
long-span bridges in Norwegian fjords has created a need for
reformulating the calculation format and the physical quantities used
to describe the properties of wind and the associated wind-induced
effects on bridge decks. Parts of a new probabilistic format
describing the incoming, undisturbed wind is presented. It is
expected that a fixed probabilistic format will facilitate a more
physically consistent and precise description of the wind conditions,
which in turn increase the accuracy and considerably reduce
uncertainties in wind load assessments. Because the format is
probabilistic, a quantification of the level of safety and
uncertainty in predicted wind loads is readily accessible. A simple
buffeting response calculation demonstrates the use of probabilistic
wind data in the assessment of wind loads and responses. Furthermore,
vortex-induced fatigue damage is discussed in relation to
probabilistic wind turbulence data and response measurements from
wind tunnel tests. Keywords.
Buffeting loads,
Long-span bridges, Resonant response, Probabilistic wind data,
Vortex-induced vibrations, Wind data format. COTech108: Super-long bridges with floating towers: the role of multi-box decks and Hardware-In-the-Loop technology for wind tunnel tests. A
Zasso, T Argentini, I Bayati, M Belloli, D Rocchi Abstract.
The super long fjord crossings in E39 Norwegian project pose new
challenges to long span bridge design and construction technology.
Proposed solutions should consider the adoption of bridge deck with
super long spans or floating solutions for at least one of the
towers, due to the relevant fjord depth. At the same time, the
exposed fjord environment, possibly facing the open ocean, calls for
higher aerodynamic stability performances. In relation to this
scenario, the present paper addresses two topics: 1) the aerodynamic
advantages of multi-box deck sections in terms of aeroelastic
stability, and 2) an experimental setup in a wind tunnel able to
simulate the aeroelastic bridge response including the wave forcing
on the floating. COTech110: Full-Scale Monitoring of Wind and
Suspension Bridge Response Jonas
T. Snæbjörnsson, Jasna B. Jakobsen, Etienne Cheynet, Jungao Wang Abstract.
Monitoring of real structures is important for many reasons. For
structures susceptible to environmental actions, fullscale
observations can provide valuable information about the environmental
conditions at the site, as well as the characteristics of the
excitation acting on the structure. The recorded data, if properly
analyzed, can be used to validate and/or update experiments and
models used in the design of new structures, such as the load
description and modelling of the structural response. Various aspects
of full-scale monitoring are discussed in the paper and the
full-scale wind engineering laboratory at the Lysefjord suspension
bridge introduced. The natural excitation of the bridge comes from
wind and traffic. The surrounding terrain is complex and its effect
on the wind flow can only be fully studied on site, in full-scale.
The monitoring program and associated data analysis are described.
These include various studies of the relevant turbulence
characteristics, identification of dynamic properties and estimation
of wind- and traffic induced response parameters. The overall
monitoring activity also included a novel application of the remote
optical sensing in bridge engineering, which is found to have an
important potential to complement traditional “single-point” wind
observations by sonic anemometers. Keywords. Suspension bridge, Monitoring, Wind loading, Turbulence, structural response
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