National Conference Emerging trends of Energy Conservation in

Due to this thickness the wind speed is distributed in a power law profile from the ground
surface in the vertical direction. So it is necessary to represent the microclimate wind
condition which can be interpolated from the reference meteorological wind data by the
following equation [22].
Where,
Approach wind speed at upwind wall height H
Hourly wind speed from a nearby meteorological station
Atmospheric boundary layer thickness at meteorological station
Height at which the anemometer that measures (generally 10 m)
Atmospheric boundary layer exponent at meteorological station
Wall height at which approach wind (upwind) speed is required
Atmospheric boundary layer thickness at approach wind speed terrain
Category.
However, the above equation gives the flow speed only, for estimation of the direction,
explicit modelling can be included or implicit methods can be applied in the domain upwind
region representing the site obstruction, which will then create an internal boundary layer and
produce the flow speed and direction.
Finally the distribution of over the surface will be based on values of wind in close
proximity (micro climate) to the wind catcher (which shall be generated with CFD)
considering equations 3, 2 and 1 respectively.
3.2. Analysis Plan
This study aims at testing air flow in a wind catcher and at the same time gain better
understanding how to integrate the real site boundary conditions in CFD. Hughes et al., [12]
in their paper has described the major design criteria for a wind catcher which are based on, “
Topography, climatic conditions, personal experience of architects, social positions of the
occupants and variation in height, cross-section of air channel, number of openings, size and
positioning of opening, form construction materials, and placement of the tower with respect
to the building.”
Montezeri et al., [13] also emphasized that, the key working condition as the pressure
differential between the air inlet and exhaust of the device. So the ambient air flow
characteristics, i.e., the speed, direction and frequency of occurrence will determine the
physical/architectural parameters of the wind tower and its openings to maximize the pressure
differential.
For mono-directional device, the direction of wind is most important to keep it functioning.
When incident wind blows from other than its design range, the wind catcher will function as
a solar chimney and flow will be reversed [12].
(3)