Abstract:
The flow fields entering intake forms oriented into a
steady flume flow has been observed and quantified. This
data is applied to a model of zooplankton sampler
performance, to predict the fraction of the sampled fluid
from which no animals will escape under conditions similar
to those of the tests. Flume flow speeds (≈5 cm/s) and
intake pumping rate (≈33 gal/min) are scaled by a factor of 20 in the model, while test form dimensions (4 and 7 inch throats and 12 inch outside diameters) are considered to be
full-size for the prototype pump samplers. The data
presented can be applied to other flow and geometrical scales.
The 'lethal cone' and critical fluid deformation rate
envelopes are evaluated for eleven intake forms: pointed,
bullet-shaped, funnel-shaped, rounded and square-ended. The
sharply-pointed intake performed test, for tow speed ≈100
cm/s, swimming speed=30 cm/s and Dc=1. 0 sec-1. 'Sure
capture' is predicted in 83% of the sampled water. The four
funnel-shaped forms follow consecutively in a rank ordering,
with efficiencies, of 77% to 68%.
