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Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  Transactions of the ASAE. 45(1): 201–214. (doi: 10.13031/2013.7872) @2002
Authors:   H. Yu, S. J. Hoff
Keywords:   Non–isothermal, Archimedes number, Momentum ratio, Airflow, Slot–ventilated

Experiments using two scalemodels were conducted to study nonisothermal airflow similarity in a ceiling slotventilated agricultural enclosure. The main criteria used for determining similarity were airflow pattern similarity, occupied zone airspeed, and temperature similarity. For agricultural ventilation issues, these were projected to be paramount to a successful scalemodel study. The current study, based on past agricultural ventilation studies, focused attention on the Archimedes number (Ar) and Momentum ratio (Rm) as the similitude criteria for nonisothermal airflow. Results indicated that Ar is the appropriate similitude criteria for nonisothermal airflow patterns under strong buoyancyaffected conditions where Ar > 0.015. With increasing airflow or decreasing temperature differences, resulting in a lower buoyancyaffected airjet, Rm with a consistent overall temperature differential was determined to be the appropriate similitude criteria. This study focused on practical considerations for conducting scale mode studies such as scalemodel conditions measured in the animal occupied zone and its relation to expected prototype behavior.

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