Wind Energy

52 E. Moryń-Kucharczyk and R. Gnatowska
Fig. 9.4. Computational distributions of a) stream function b) amplitude of transverse
velocity oscillations
simulation mentioned above provided the mean velocity distributions as
well as characteristics of turbulence structure around tandem arrangement.
The special emphasize has been put on intensity of velocity oscillation in
space around bluff-bodies. The sample results, shown in Fig. 9.4a present the
instantaneous computational distributions of stream function corresponding
to different dynamic states of the flow in body system environment. The centreline
distributions of amplitude of transverse velocity oscillations are also
juxtaposed in Fig. 9.4b. One may suppose that transport of pollutants is intensified
by periodical velocity component, generated in flow around bluff-bodies
arrangement, especially for the critical body spacing. In this case the maximum
of concentration, move forwards in the centreline of the wake.
9.3 Conclusions
In an experimental study of bluff-bodies tandem arrangement the significant
changes have been observed in the concentration field of the tracer gas for different
spacing ratio. Depending on body spacing the maximum concentration
of CO2 is localized outside of the gap (double peak) or migrates towards the
centreline. The interbody gap is filled up by the emitted gas more intensively
as the level of energy of oscillating velocity component increases (critical body
spacing). The problem needs further studies.
References
1. Jar˙za J, Gnatowska R (2004) Lock-on effect on unsteady loading of rigid bluff -
body in tandem arrangement. Proceedings of International Conference Urban
Wind Engineering and Buildings Aerodynamics Cost C14. Rhode-St-Genese
Belgium