Abstract:
Consideration is
given to the use of.vane (DVA) and
propeller anemometers in the sensing of atmospheric turbulence.
Careful
experimental measurements of the DVA dynamic response
contributes to this consideration. Quantification of the airflow
within and above a Sitka
spruce canopy then follows. Statistics
indicate the
non-Gaussianity of the air turbulence Such forms
are
interpreted through the intermittency of turbulence and
investigated by a conditional sampling scheme. Nindspeed spectra
have
ragged forms, showing them to be vastly modified by the
combined effects of the
canopy-imposed scales, together with the
canopy's elemental vortex shedding frequencies and resonances.
Studies of tree motions show the
possibility of_a simple connection
between the resonances of the
separate canopy elements, which
could
provide the tree with an atmospheric shock-absorbing structure,
supportive of its observed response to turbulence The ensuing
proposal of a hypothetical qualitative mechanical design principle
based on aeroelastic
similaritynay bebeneficial to the tree's
survivability in conditions of strong atmospheric turbulence.
