P1.228 Wednesday, Jan. 4 Baffling bird noses: Modeling the effects of turbinate structure on airflow dynamics in ostriches and turkeys BOURKE, Jason*; WITMER, Lawrence; Ohio University, Athens firstname.lastname@example.org
Respiratory turbinates in birds vary in their structure and complexity. Some are relatively simple infoldings of the cartilaginous nasal capsule while others exhibit a more scrolled, branch-like formation similar to that of many mammals. The effects of these turbinates on airflow through the nasal passage have not been fully explored. Earlier models of avian nasal airflow relied on general fluid dynamics to estimate airflow patterns through the nasal passage. To better assess these flow patterns, a computational fluid dynamics (CFD) analysis was performed on the nasal passages of a galliform (turkey) and a ratite (ostrich). Results from the turkey uncovered two major routes of airflow through the nasal passage. The majority of inspired air traveled past the rostral and middle conchae in a cyclonic manner, ultimately exiting at the choana. A second, lower-speed airstream occurred on the medial side of the rostral concha, bypassing the middle concha and flowing around the caudal concha within the olfactory chamber. This secondary flow appeared to be the main route in which odorant molecules would enter the olfactory chamber. These data validate previous suppositions that the atrial and rostral conchae act as baffles that split and redirect the incoming air field. Results from the turkey model were compared to a CFD model of an ostrich, which lacks an atrial concha. Differences in airflow between these two taxa may relate to the role of olfaction in the ecology of each taxon.