No abstract

A numerical investigation has been conducted to analyze the influence of the dynamic ground effect on the aerodynamic characteristics of a rectangular wing. The numerical model is based on a three-dimensional panel method and the ground effect is analyzed using the method of images. Before simulating the wing approaching the ground, the model developed was tested assuming fixed height and the results were examined by comparison to analytical and numerical results showing a good agreement. Then, the dynamic ground effect was investigated for two flight conditions: constant rate of descent and varying rate of descent. The results obtained by dynamic ground effect and those ones computed using static ground effect were compared evidencing that the static ground effect underpredicts the lift coefficient and overpredicts the induced drag coefficient. In addition, for these flight conditions, the lift coefficient increases when non-dimensional height decreases observing that it is more significant for a constant value of rate of descent, and the induced drag coefficient decreases while non-dimensional height reduces evidencing a significant decrease for a varying rate of descent. Finally, the effect of the flight path angle was evaluated demonstrating that the lift and the induced drag coefficients decrease with more negative flight path.

A numerical investigation has been developed to evaluate the influence of dynamic ground effect on the aerodynamic coefficients of a wing using a panel method. This simulates unsteady flow by the time-marching method with a deformable free wake. The image method is used to model ground effect. Lift, induced drag, and pitching moment coefficients were obtained considering fixed height above the ground (static ground effect) and the wing in sink and flare maneuvers (dynamic ground effect). The results at static ground effect were compared with analytical and numerical results in order to verify and validate the created panel code, and they are acceptable. Lift and the absolute value of the pitching moment coefficients increase and the induced drag coefficient decreases as the height diminishes. Although the trends in static and dynamic ground effect are similar, the aerodynamic coefficients achieved in static ground effect are less affected than those ones calculated by simulations of the wing approaching the ground. Linear models of the wing in ground effect were developed by using the data of constant rate of descent and flare maneuvers. The sink rate produces significant variations in the aerodynamic coefficients of a wing. Nomenclature b= wingspan CL, CD, CM = lift, drag, and pitching moment coefficients CL0, CD0, CM0 = lift, drag, and pitching moment coefficients at zero angle of attack CLq, CDq, CMq = variation of lift, drag, and pitching moment coefficients with pitch rate CLh, CDh, CMh = variation of lift, drag, and pitching moment coefficients with c H CLα, CDα, CMα = lift, drag, and pitching moment slopes

. CC-BY-NC-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/238956 doi: bioRxiv preprint first posted online Dec. 23, 2017; 3 Abstract 30 Sea turtles are a keystone species and are highly sensitive to changes in their environment, 31 making them excellent environmental indicators. In light of environmental and climate changes, 32 species are increasingly threatened by pollution, changes in ocean health, habitat alteration, and 33 plastic ingestion. There may be additional health related threats and understanding these threats is 34 key in directing future management and conservation efforts, particularly for severely reduced 35 sea turtle populations. Hawksbill turtles (Eretmochelys imbricata) are critically endangered, with 36 those in the eastern Pacific Ocean (Mexico-Peru) considered one of the most threatened sea turtle 37 populations in the world. This study establishes baseline health parameters in hematology and 38blood biochemistry as well as tested for heavy metals and persitent organic pollutants in eastern 39Pacific hawksbills at a primary nesting colony located in a mangrove estuary. Whereas 40 hematology and biochemistry results are consistent with healthy populations of other species of 41 sea turtles, we identified differences in packed cell volume, heterophils and lympohcyte counts, 42and glucose when comparing our data to other adult hawksbill analysis (1), (2), (3). Our analysis 43 of heavy metal contamination revealed a mean blood level of 0.245 ppm of arsenic, 0.045 ppm of 44 lead, and 0.008 ppm of mercury. Blood levels of persistent organic pollutants were below the 45 laboratory detection limit for all turtles. Our results suggest that differences in the feeding 46 ecology of eastern Pacific hawksbills in mangrove estuaries may make them less likely to 47 accumulate persistent organic pollutants and heavy metals in their blood. These baseline data on 48 blood values in hawksbills nesting within a mangrove estuary in the eastern Pacific offer 49 important guidance for health assessments of the species in the wild and in clinical rehabilitation 50 facilities, and underscore the importance of preventing contamination from point and non-point 51 sources in mangrove estuaries, which represent primary habitat to hawksbills and myriad other 52 marine species in the eastern Pacific Ocean. 53