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Respiratory evaporative cooling in necks of birds and sauropods



From: Ben Creisler
bcreisler@gmail.com


A recent paper that may be of interest:

N.S. Sverdlova, F. Arkali, U. Witzel & S.F. Perry (2013)
Computational fluid dynamics model of avian tracheal temperature
control as a model for extant and extinct animals.
Respiratory Physiology & Neurobiology 189(1): 67–75
http://dx.doi.org/10.1016/j.resp.2013.06.012
http://www.sciencedirect.com/science/article/pii/S1569904813002103





Respiratory evaporative cooling is an important mechanism of
temperature control in bird. A computational simulation of the
breathing cycle, heat and water loss in anatomical avian trachea/air
sac model has not previously been conducted. We report a first attempt
to simulate a breathing cycle in a three-dimensional model of avian
trachea and air sacs (domestic fowl) using transient computational
fluid dynamics. The airflow in the trachea of the model is evoked by
changing the volume of the air sacs based on the measured tidal volume
and inspiratory/expiratory times for the domestic fowl. We compare
flow parameters and heat transfer results with in vivo data and with
our previously reported results for a two-dimensional model. The total
respiratory heat loss corresponds to about 13–19% of the starvation
metabolic rate of domestic fowl. The present study can lend insight
into a possible thermoregulatory function in species with long necks
and/or a very long trachea, as found in swans and birds of paradise.
Assuming the structure of the sauropod dinosaur respiratory system was
close to avian, the simulation of the respiratory temperature control
(using convective and evaporative cooling) in the extensively
experimentally studied domestic fowl may also help in making
simulations of respiratory heat control in these extinct animals.