Aerodynamics of the Cupped Wings during Peregrine Falcon’s Diving Flight

During a dive peregrine falcons can reach velocities of more than 320 km/h and makes themselves the fastest animals in the world. The aerodynamic mechanisms involved are not fully understood yet and the search for a conclusive answer to this fact motivates the three-dimensional (3-D) flow study. Especially the cupped wing configuration which is a unique feature of the wing shape in falcon peregrine dive is our focus herein. In particular, the flow in the gap between the main body and the cupped wing is studied to understand how this flow interacts with the body and to what extend it affects the integral forces of lift and drag. Characteristic shapes of the wings while divingare studied with regard to their aerodynamics using computational fluid dynamics (CFD). The results of the numerical simulations via ICEM CFD and OpenFOAM show predominant flow structures around the body surface and in the wake of the falcon model such as a pair of body vortices and tip vortices. The drag for the cupped wing profile is reduced in relation to the configuration of opened wings (without cupped-like profile) while lift is increased. The purpose of this study is primarily the basic research of the aerodynamic mechanisms during the falcon’s diving flight. The results could be important for maintaining good maneuverability at high speeds in the aviation sector

Diving-flight aerodynamics of a peregrine falcon (Falco peregrinus)

This study investigates the aerodynamics of the falcon Falco peregrinus while diving. During a dive peregrines can reach velocities of more than 320 km h⁻¹. Unfortunately, in freely roaming falcons, these high velocities prohibit a precise determination of flight parameters such as velocity and acceleration as well as body shape and wing contour. Therefore, individual F. peregrinus were trained to dive in front of a vertical dam with a height of 60 m. The presence of a well-defined background allowed us to reconstruct the flight path and the body shape of the falcon during certain flight phases. Flight trajectories were obtained with a stereo high-speed camera system. In addition, body images of the falcon were taken from two perspectives with a high-resolution digital camera. The dam allowed us to match the high-resolution images obtained from the digital camera with the corresponding images taken with the high-speed cameras. Using these data we built a life-size model of F. peregrinus and used it to measure the drag and lift forces in a wind-tunnel. We compared these forces acting on the model with the data obtained from the 3-D flight path trajectory of the diving F. peregrinus. Visualizations of the flow in the wind-tunnel uncovered details of the flow structure around the falcon's body, which suggests local regions with separation of flow. High-resolution pictures of the diving peregrine indicate that feathers pop-up in the equivalent regions, where flow separation in the model falcon occurred

Vortices enable the complex aerobatics of peregrine falcons

The peregrine falcon (Falco peregrinus) is known for its extremely high speeds during hunting dives or stoop. Here we demonstrate that the superior manoeuvrability of peregrine falcons during stoop is attributed to vortex-dominated flow promoted by their morphology, in the M-shape configuration adopted towards the end of dive. Both experiments and simulations on life-size models, derived from field observations, revealed the presence of vortices emanating from the frontal and dorsal region due to a strong spanwise flow promoted by the forward sweep of the radiale. These vortices enhance mixing for flow reattachment towards the tail. The stronger wing and tail vortices provide extra aerodynamic forces through vortex-induced lift for pitch and roll control. A vortex pair with a sense of rotation opposite to that from conventional planar wings interacts with the main wings vortex to reduce induced drag, which would otherwise decelerate the bird significantly during pull-out. These findings could help in improving aircraft performance and wing suits for human flights

Measuring Behavioral Regulation in Four Societies

The present study examined the psychometric properties of scores from a direct measure of behavioral regulation, the Head–Toes–Knees–Shoulders task (HTKS) with 3- to 6-year-old children in the United States, Taiwan, South Korea, and China. Specifically, we investigated (a) the nature and variability of HTKS scores, including relations to teacher-rated classroom behavioral regulation; and (b) relations between the HTKS and early mathematics, vocabulary, and literacy skills. Higher HTKS scores were significantly related to higher teacher ratings of classroom behavioral regulation in the United States and South Korea but not in Taiwan and China. Also, higher HTKS scores were significantly related to higher early mathematics, vocabulary, and literacy skills beyond the influence of demographic variables and teacher-rated classroom behavioral regulation. These  initial findings suggest that HTKS scores may be interpreted as reflecting early behavioral regulation in these 4 societies and that behavioral regulation is important for early academic success in the United States and in Asian countries.The present study examined the psychometric properties of scores from a direct measure of behavioral regulation, the Head-Toes-Knees-Shoulders task (HTKS) with 3- to 6-year-old children in the United States, Taiwan, South Korea, and China. Specifically, we investigated (a) the nature and variability of HTKS scores, including relations to teacher-rated classroom behavioral regulation; and (b) relations between the HTKS and early mathematics, vocabulary, and literacy skills. Higher HTKS scores were significantly related to higher teacher ratings of classroom behavioral regulation in the United States and South Korea but not in Taiwan and China. Also, higher HTKS scores were significantly related to higher early mathematics, vocabulary, and literacy skills beyond the influence of demographic variables and teacher-rated classroom behavioral regulation. These initial findings suggest that HTKS scores may be interpreted as reflecting early behavioral regulation in these 4 societies and that behavioral regulation is important for early academic success in the United States and in Asian countries

4D visualization study of a vortex ring life cycle using modal analyses

In this study, the life cycle of a vortex ring is visualized and simultaneously investigated in a three-dimensional (3D) domain and time resolved for an observer in a reference frame moving with the ring. By traversing the system, the object of interest is captured within the measurement volume during the entire cycle. The 4D (time-resolved 3D) data gained from the experiment are postprocessed by using modal analyses such as proper orthogonal decomposition and dynamic mode decomposition (DMD). The latter is used to reconstruct the vortex dynamics by means of the Q values, based on the most dominant modes in the DMD. These modal analyses allow reconstructing the dominant dynamics of the behavior of the secondary structures and their interaction with the vortex core. The visualization for the vortex ring at ReΓ = 5500 shows the well-known azimuthal instability and its growth at n = 6 in our experiments. As the process of transition further develops, we found a zig-zag-like mesh of tilted secondary structure and finally, helical coil-type vortex ribbons wrapped around the core, which emerge in the late-stage process. It is hypothesized that the initial state of this process is the emergence of a pair of standing helical waves both counterbalancing each other at the beginning and forming the zig-zag pattern. Azimuthal core flow is only weak in this phase. Later in the transition, one of the helical waves starts to take over the other and finally dominates. This results in the helical coil-type vortex structure seen in the reconstructed results, which goes with the increase in axial flow along the core. The hypothesis of coexisting helical waves is drawn from similarities in the transition of attached vortex rings in axisymmetric wakes

Three years of x+y scheduling: Longitudinal assessment of resident and faculty perceptions

PURPOSE: Five pediatric residency programs implemented true X+Y scheduling in 2018 where residents have continuity clinic in blocks rather than half-day per week experiences. We report the impact X+Y scheduling has on pediatric resident and faculty perceptions of patient care and other educational experiences over a three-year timeframe. METHODS: Electronic surveys were sent to residents and faculty of the participating programs prior to implementing X+Y scheduling and annually thereafter (2018 - 2021). Survey questions measured resident and faculty perception of continuity clinic schedule satisfaction and the impact of continuity clinic schedules on inpatient and subspecialty rotations. Data were analyzed using z-tests for proportion differences. RESULTS: 186 residents were sent the survey pre-implementation and 254-289 post-implementation with response rates ranging from 47%-69%. 378- 395 faculty members were sent the survey with response rates ranging from 26%-51%. Statistically significant (p\u3c0.05) sustained perceived improvements over three years with X+Y were seen in outpatient continuity, inpatient workflow, and time for teaching both inpatient and in continuity clinic. CONCLUSIONS: X+Y scheduling can lead to perceived improvements in various aspects of pediatric residency programs. Our study demonstrates these improvements have been sustained over three years in the participating programs. WHAT\u27S NEW: X+Y scheduling in pediatric residency programs is rather novel and there is a paucity of literature evaluating its use. We report three years of outcome data from the only ACGME-approved pilot of X+Y scheduling in pediatric residency

Impact of X+Y scheduling on pediatric resident and faculty perceptions of education and patient care

PURPOSE: Traditional half-day per week continuity clinic experiences can lead to fragmented education in both the inpatient and outpatient arenas. Five pediatric residency programs were granted the ability from the ACGME to create X+Y scheduling where residents have continuity clinic in blocks rather than half-day per week experiences. The aim of this study is to assess the impact X+Y scheduling has on pediatric resident and faculty perceptions of patient care and other educational experiences. METHODS: Electronic surveys were sent to residents and faculty of the participating programs both prior to and 12 months after implementing X+Y scheduling. Survey questions measured resident and faculty perception of continuity clinic schedule satisfaction and the impact of continuity clinic schedules on inpatient and subspecialty rotation experiences using a 5-point Likert Scale. Data were analyzed using z-tests for proportion differences for those answering Agree or Strongly Agree between baseline and post-implementation respondents. RESULTS:126 out of 186 residents (68%) responded pre-implementation and 120 out of 259 residents (47%) responded post-implementation. 384 faculty members were sent the survey with 51% response pre-implementation and 26% response at 12 months. Statistically significant (p CONCLUSIONS: From both resident and faculty perspectives, X+Y scheduling may improve several aspects of patient care and education. X+Y scheduling could be considered as a potential option by pediatric residency programs, especially if validated with more objective data