The effect of wind speed and wetting on thermal resistance of the barn owl (Tyto alba). I: Total heat loss, boundary layer and total resistance

McCafferty, D. (1997) The effect of wind speed and wetting on thermal resistance of the barn owl (Tyto alba). I: Total heat loss, boundary layer and total resistance. Journal of Thermal Biology, 22(4-5), pp. 253-264. (doi: 10.1016/S0306-4565(97)00020-X)

Abstract

1. 1. The sensible heat loss and thermal resistance of a barn owl (Tyto alba) were determined using a heat transfer model in a wind tunnel. 2. 2. Heat loss was a linear function of wind speed and increased by 60% between 0 and 7 m s−1. Wetting the model increased heat loss by 30%. 3. 3. Boundary layer resistance of the model decreased from 223 s m−1 in still air to 56 s m−1 at a wind speed of 1.3 m s−1 and remained constant at wind speeds up to 7 m s−1. 4. 4. The relationship between Nusselt and Reynolds numbers for the model was linear, as was the relationship for cylinders over the range in Reynolds numbers. Nusselt numbers for the plumage-covered model were, however, 30% lower than those derived for the uncovered model. 5. 5. Total thermal resistance of the model was 508 s m−1 (dry) and 486 s m−1 (wet), decreasing by almost 60% from 0 to 7 m s−1. There was a nonlinear decrease in total resistance with increasing wind speed, mainly due to the change in boundary resistance between 0 and 1.3 m s−1. Author Keywords: Thermal resistance; heat loss; wind speed; wetting; barn owl; Tyto alba

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: McCafferty, Dr Dominic
• Authors: McCafferty, D.
• College/School: College of Social Sciences > School of Education; College of Medical Veterinary and Life Sciences > School of Life Sciences
• Journal Name: Journal of Thermal Biology
• ISSN: 0306-4565