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- Offer Profile
- Welcome to Wind Engineering
Section at Kyushu University research institute for applied mechanics (RIAM).
Our research interests include, problems of fluid dynamics related to wind
environments such as airflow over complex terrain and urban canopy, effect
of wind forces on buildings and structures, and wind energy as clean and
renewable energy. As a part of the research on renewable energy source, we
have developed a new wind turbine technology called "Wind Lens". Development
of the wind-lens turbine has recently entered new stage which consists of
two main components. They are augmentation of wind lens application to mid
to large size wind turbine and utilization of the wind-lens turbines as a
core part of future off-shore energy farm.
- Wind Engineering Section attacks problems related to
turbulence of the atmospheric boundary layer, prediction of wind systems
over local topography, aerodynamic characteristics of bluff bodies, also
development of new wind turbine system, and computational fluid dynamics in
wind engineering. As our tools for the research, we utilize various wind
engineering facilities including boundary-layer wind tunnel，thermally
stratified wind tunnel and water tanks.
- Wind power is proportional to the wind speed cubed. If
we can increase the wind speed with some mechanism by utilizing the fluid
dynamic nature around a structure, namely if we can capture and concentrate
the wind energy locally, the output power of a wind turbine can be increased
substantially. At wind energy section of Kyushu University, a new efficient
wind power turbine system has been developed. This system has an diffuser
shroud at the circumference of its rotor to embody the wind energy
concentration. The diffuser shroud is now named "Wind lens". To apply the
wind-lens structure to a larger size turbine, we have developed a compact
collection-acceleration device. There are several ongoing projects in which
the wind-lens turbines are involved.
Development of wind energy and new wind turbine system
- To contribute to increase the share of clean renewable
energy sources, we have been developing a new effective wind power
concentration system. This technology is named "Wind Lens". The Wind Lens
can improve output power of wind turbine by a factor of 2 to 3 compared to
conventional wind turbine that has the same rotor radius. This research is
also a part of new generation of off-shore power plant.
How does the Wind Lens work?
- Strong vortices created by the diffuser and the brim of
the Wind Lens produce low pressure region behind the turbine. This increased
pressure difference that helps the wind to flow more into the Wind Lens.
Next stage of the development of Wind Lens
- Since wind load on the Wind-Lens turbine is larger than
typical wind turbines, application of the Wind Lens to turbines in larger size
faces structural challenge. As a part of development of next generation
Wind-Lens turbines, two mid-size (100 kW with wind speed 12m/s) wind-lens
turbines have been currently constructed at Ito campus of Kyushu University.
This version of the turbine has much larger structural dimensions than our
5kW turbines. The 100 kW turbine has a rotor which spans 12.8 m in diameter,
diffuser diameter 15.4m, and the whole structure reaches 34 m high above the
ground. This project is an important mile stone toward an ongoing project of
off-shore energy farm.
The first stage of off-shore wind farm development has begun. A set of water
tank experiments has been carried out recently as a preparation for near
future construction of off-shore wind farm built on a floating structure on
Hakata-bay (18m in float diameter, with a couple of 5kW Wind-Lens turbines).
We are preparing for the construction possibly as early as Autumn 2011. This
plan leads us to the second stage development of the wind farm, which
consists of larger floating structure (60m in diameter, with a couple of
100kW Wind-Lens turbines). The planned location is Genkai-nada Sea, Fukuoka.
Hot research topics
Turbulence structure and transport characteristics of
the atmospheric boundary layer
- We are
trying to find out characteristics of exchange and transport processes of
momentum, heat and constituent occurring inside the turbulent atmospheric
boundary layer. A large number of numerical simulations are carried out as
much as physical simulations such as large wind tunnel experiment.
Aerodynamic characteristics and flutter phenomena of
- Behavior of air flow around a body in non-streamlined
shape (bluff body) placed in the atmospheric boundary layer is very
interesting. We aim for establishing a general explanation for flow around
the bluff bodies. Also, a body in a flow often vibrates. Sometimes the
amplitude of the oscillation increases naturally and causes serious damages.
This is called "flutter". We study about the mechanism and effective
prevention of the flutter.
Prediction of wind systems over local topographic
features (RIAM-COMPACT package)
- We study air flow over and around buildings, minor
landforms, also over complex terrain and urban canopy by using wind tunnel
experiments and carrying out various field works to establish effective
method of predicting micro and local wind conditions. Numerical approach
which has been rapidly advancing in recent years in fluid dynamics is also
one of our strong tools to attack the problems.
Exchange process of momentum, heat and constituent
between the atmosphere and ocean
- Refining meteorological method to determine amount of
carbon dioxide exchanged between the atmosphere and ocean (including eddy
correlation method, aerodynamic technique of gradient method, and bulk
method) is also one of our research topics. At the same time, we are trying
to find out relation between local climate and the amount of the exchanged