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Natural Flight
Published in Malcolm S. Gordon, Reinhard Blickhan, John O. Dabiri, John J. Videler, Animal Locomotion, 2017
Wings of conventional aircraft in steady linear motion create an upward force by deflecting the horizontal oncoming airflow down. A model wing in a recirculating water tunnel seeded with tiny particles shows the flow quantitatively to fully appreciate the interaction between a conventional wing and the fluid flow (Figure 4.13). The picture shows a cross section through a transparent Perspex model of the arm wing of a northern fulmar, an oceanic bird with excellent gliding capacities. The wing section is modeled on the cross section near the end of the arm wing, just proximal of the wrist joint. The model is uniform across the entire span of the width of the water tunnel. The chord length from the leading to the trailing edge is 9.3 cm, a value that is smaller than the real chord length of 12.5 cm. The flow velocity in the water tunnel is 0.5 m s−1, to match a Re number (based on the chord length) of a fulmar wing in air gliding at an airspeed of about 20 km h−1. The angle of attack (between the tangent to the underside of the wing cross section and the horizontal) is about 6°. Neutrally buoyant particles are illuminated by a thin laser sheet halfway down the span of the model. The sheet shines through the Perspex model and illuminates all the particles moving around the wing section. Two successive digital images, taken 0.004 s apart, show the direction and distance covered during that time of each particle in the plane of the sheet. The two-dimensional velocity vector diagram is based on these measurements.
Skill and Luck
Published in James Reason, The Human Contribution, 2017
When the second engine stopped, the aircraft was at 35,000 feet and 65 miles from Winnipeg. All the electronic gauges in the cockpit had ceased to function, leaving only stand-by instruments operative. The First Officer, an ex-military pilot, recalled that he had flown training aircraft in and out of Gimli, some 45 miles away. When it became evident that they would not make it to Winnipeg, the captain, in consultation with air traffic control, redirected the aircraft to Gimli, now 12 miles away on the shores of Lake Winnipeg. The report continues as follows: Fortunately for all concerned, one of Captain Pearson’s skills is gliding. He proved his skill as a glider pilot by using gliding techniques to fly the large aircraft to a safe landing. Without power, the aircraft had no flaps or slats to control the rate and speed of descent. There was only one chance of landing. By the time the aircraft reached the beginning of the runway, it had to be flying low enough and slowly enough to land within the length of the 7,200 foot runway.As they approached Gimli, Captain Pearson and First Officer Quintal discussed the possibility of executing a side-slip to lose height and speed close to the beginning of the runway. This the Captain did on the final approach and touched down within 800 feet of the threshold.2
Traumatic Brain Injury and Aeromedical Licensing
Published in Anthony N. Nicholson, The Neurosciences and the Practice of Aviation Medicine, 2017
Those flying light planes within the United Kingdom or involved in other air sports such as ballooning or gliding can seek a National Private Pilot Licence in which their medical practitioner has to countersign a self-declaration of fitness. The practitioner uses criteria provided by the UK Driver and Vehicle Licensing Agency: Group 1 criteria (equivalent to car driving) for solo-flying and Group 2 criteria (equivalent to driving heavy goods vehicles) for flying with passengers. These procedures are run by the relevant air sports governing bodies and overseen by the Civil Aviation Authority. The risk level for Group 1 is set at 20 per cent and for Group 2 at 2 per cent, based on actuarial approaches to initial risk and seizure-free period and the estimate therefrom of residual risk.
Towards a systems framework for the assurance of maritime autonomous systems
Published in Australian Journal of Multi-Disciplinary Engineering, 2023
Jawahar Bhalla, Stephen C. Cook, David J. Harvey
The invention of flight was perhaps one of the greatest of innovations of modern times, fundamentally transforming human life by enabling rapid connectivity across the globe and beyond into exploration of our solar system. Modern aviation is the safest mode of transport, with data from the Australian Civil Aviation Safety Authority (CASA) validating a decrease in accident rates over the past five years (page 12 [C.A.S.A. 2021]). However, safety was not an attribute of early aviation. Pioneers such as Otto Lilienthal (the ‘Glider King’ and the ‘father of flight’), met his death tragically on the 12 August 1896 in a gliding accident (Team, t.Y 2020). The need to safely develop ‘muscle memory’ to instinctively react with the right control inputs to varying environmental conditions resulted in the first flight simulator for the French Antoinette aircraft, appropriately named the ‘French half-barrel with wings’ (Hayes and Langlois 2005) (Figure 5).
On the propulsion of capsule-shaped organisms next to slippery rigid boundaries
Published in Waves in Random and Complex Media, 2023
Zeeshan Asghar, Rehman Ali Shah, Wasfi Shatanawi, Muhammad Asif Gondal
A complex wavy sheet gliding over an Ellis slime is considered with slip effects. The biomechanics of gliding bacterium movement are quantitatively simulated using Navier-Stokes equations under creeping and long-wavelength assumptions. The reduced DE is solved numerically via bvp4c. The DE solver is further combined with modified secant algorithm to calculate flow rate, gliding speed, and energy loss. Slime velocity of slime and level curves are also expounded. The key points are as follows: The speed of a complex wavy sheet is an increasing function of the slip parameter.The Ellis fluid parameters () are resistive to gliding speed.Glider consumed less power in the course of gliding on Ellis slime with slip effects as compared to Newtonian slime with no-slip effects.Slime velocity near the substrate is directly proportional to bacterial speed.The recirculating zones appearing in the central region (for ) disappear in the case of large slip effects, while an opposite trend is observed with increasing material constant .
A model-based shape conceptual design framework of blend-wing-body underwater gliders with curved wings
Published in Ships and Offshore Structures, 2023
Wenxin Wang, Xinjing Wang, Huachao Dong, Peng Wang, Jiangtao Shen
Protecting the maritime environment and utilising marine resources have gained more attention during the last few decades (Rudnick 2016). Underwater gliders (UGs), a novel class of autonomous underwater vehicles (AUVs), are superior in ocean exploration thanks to their benefits of low cost and extensive gliding range (endurance) (Rudnick et al. 2004). UGs achieve vertical zigzag gliding and spatial spiral motion by buoyancy control and attitude adjustment (Rudnick et al. 2004). Based on the concept design of UGs proposed by Stommel (1989), many UGs have been developed such as Slocum (Webb et al. 2001), Sea-glider (Eriksen et al. 2001), Sea-wing (Yu et al. 2013), Spray (Sherman et al. 2001), X-ray (Arima et al. 2014), Z-ray (D’Spain et al. 2007) and so on. The existing UGs can fall into two types by their shapes. The first type is termed conventional UGs, composed of a revolution body and fixed-wing. Slocum (Webb et al. 2001 and Stommel 1989), Sea-glider (Eriksen et al. 2001), Spray (Sherman et al. 2001) and Sea-wing (Yu et al. 2013) are typical representatives of this type of glider. Different from the mentioned general revolving body shape, several nonconventional outlines (X-ray (Arima et al. 2014), Z-ray (D’Spain et al. 2007), and so on) fall to the other type. To be more precise, blend-wing-body underwater gliders (BWBUGs) adopt a smooth connection between their bodies and wing to improve hydrodynamic performance, gliding range, and speed capability.