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Journal ArticleDOI

Evolutionary and Hereditary Traits of an Albatross and its Aerodynamic Optimality

01 Jun 2021-Vol. 775, Iss: 1, pp 012002
TL;DR: In this paper, a review sheds light on the traits behind an albatross's aerodynamic efficiency such as dynamic soaring, bell shaped lift distribution and provides insights into its hereditary posed encodings and evolutions.
Abstract: The aerodynamic efficiency of the albatross has always fascinated researchers and the designing of drones mimicking the albatross's aerodynamic traits have been a major area of interest for the aerospace industry. This review sheds light on the traits behind an albatross's aerodynamic efficiency such as dynamic soaring, bell shaped lift distribution and provides insights into its hereditary posed encodings and evolutions. The soaring techniques have been introduced and discussed along with the albatross's morphology and structure which is responsible for its efficiency. In addition, the albatross's navigational and foraging strategies are briefly discussed to provide a better understanding of the effects of atmospheric conditions on the albatross's flight characteristics and the limitations.
Citations
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Journal ArticleDOI
TL;DR: In this article , a flat delta wing with and without winglets at different angles of attack under low Reynolds numbers is analyzed and simulations are carried out to draw comparisons between the winglets on the basis of span-wise flow velocity vectors.
Abstract: Delta wing has numerous applications across aerospace vehicles. Highly inclined and variable swept back wings have a lot of added advantages in maneuverable fighter airplanes, supersonic cruise airliner; and modern unmanned aerial vehicles that have been equipped with and have deployed low swept back delta wings. Vortex flow across these delta wings is dominant for micro aerial vehicles and mini unmanned aerial vehicles flying at a low speed Reynolds number regime. Many experiments were carried out to study and analyze the aerodynamic flow parameters of delta wings wherein vortex sheet flow patterns were observed and studied at different angles of attack and flow parameters. In this paper we are plotting lift co-efficient and drag coefficient for a flat delta wing with and without winglets at different angles of attack under low Reynolds numbers. Furthermore, simulations are carried out to draw comparisons between the winglets on the basis of span-wise flow velocity vectors.
TL;DR: In this paper , the authors investigate various types of assaults and different types of security mechanisms that might be applied based on the network's needs and architecture to defend against network security threats.
Abstract: - Security is an important aspect of computing and networking technology. The first and most important aspect of any network design, planning, construction, and operation is the significance of a solid security strategy. Network security is becoming increasingly critical to personal computer users, businesses, and the military. With the introduction of the internet, security has become a big problem. Many security threats were made possible by the internet's structure. Because of the ease with which intellectual property can be obtained via the internet, network security is becoming increasingly important. When an attack is sent via a network, it can take several forms. Knowing the attack mechanisms enables adequate security to evolve. Many businesses protect themselves from the internet by using of Firewalls and encryption methods are examples of security measures. On global networking infrastructures, there is a vast number of personal, commercial, military, and government information, all of which necessitates different security procedures. In this research, we attempt to investigate numerous types of assaults as well as various types of security mechanisms that might be applied based on the network's needs and architecture.
References
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Journal ArticleDOI
TL;DR: In this paper, a series of aerodynamic shape optimization studies using Reynolds-averaged Navier-Stokes computational fluid dynamics with a Spalart-Allmaras turbulence model is performed.
Abstract: The blended wing body is an aircraft configuration that has the potential to be more efficient than conventional large transport aircraft configurations with the same capability. However, the design of the blended wing is challenging due to the tight coupling between aerodynamic performance, trim, and stability. Other design challenges include the nature and number of the design variables involved, and the transonic flow conditions. To address these issues, a series of aerodynamic shape optimization studies using Reynolds-averaged Navier–Stokes computational fluid dynamics with a Spalart–Allmaras turbulence model is performed. A gradient-based optimization algorithm is used in conjunction with a discrete adjoint method that computes the derivatives of the aerodynamic forces. A total of 273 design variables—twist, airfoil shape, sweep, chord, and span—are considered. The drag coefficient at the cruise condition is minimized subject to lift, trim, static margin, and center plane bending moment constraints. ...

202 citations

Journal ArticleDOI
TL;DR: Initial olfactory detection was implicated in nearly half (46.8%) of all flown approaches preceding prey-capture events, accounting for 45.5% of total prey mass captured by in-flight foraging, which offers insights into the sensory basis for area-restricted search at the large spatial scales of the open ocean.
Abstract: Wandering albatrosses (Diomedea exulans) forage over thousands of square kilometers of open ocean for patchily distributed live prey and carrion. These birds have large olfactory bulbs and respond to fishy-scented odors in at-sea trials, suggesting that olfaction plays a role in natural foraging behavior. With the advent of new, fine-scale tracking technologies, we are beginning to explore how birds track prey in the pelagic environment, and we relate these observations to models of odor transport in natural situations. These models suggest that odors emanating from prey will tend to disperse laterally and downwind of the odor source and acquire an irregular and patchy concentration distribution due to turbulent transport. For a seabird foraging over the ocean, this scenario suggests that olfactory search would be facilitated by crosswind flight to optimize the probability of encountering a plume emanating from a prey item, followed by upwind, zigzag flight to localize the prey. By contrast, birds approaching prey by sight would be expected to fly directly to a prey item, irrespective of wind direction. Using high-precision global positioning system (GPS) loggers in conjunction with stomach temperature recorders to simultaneously monitor feeding events, we confirm these predictions in freely ranging wandering albatrosses. We found that initial olfactory detection was implicated in nearly half (46.8%) of all flown approaches preceding prey-capture events, accounting for 45.5% of total prey mass captured by in-flight foraging. These results offer insights into the sensory basis for area-restricted search at the large spatial scales of the open ocean.

190 citations

Journal ArticleDOI
03 Apr 2008-Ibis
TL;DR: Evidence of the effect of krill shortage in drastically reducing Black-browed Albatross breeding success is presented to support this and the two species have largely non-overlapping winter oceanic ranges which are probably correlated with the distribution of preferred prey.
Abstract: Summary The food and feeding ecology of Black-browed Albatrosses and Grey-headed Albatrosses was studied from 1975 to 1978 at Bird Island, South Georgia. Two hundred and seventy food samples (averaging 75–85 % by weight of the mean chick feed) were collected from adults of each species in February and March. Chicks of both species received meals of the same size, of which half consisted of liquid. The three major components of the solid diet (krill, squid and fish) were similar for both albatrosses. By weight, fish represented about 35 % of the diet of both species; squid predominated (50 %) in the diet of Grey-headed Albatross, and krill (40 %) in the diet of Black-browed Albatross. Lampreys were confined to the Grey-headed Albatross and, although squid of similar sizes were taken by both species, Black-browed Albatrosses took a much greater diversity of squid. Each major prey type was associated with a characteristic amount of liquid in the complete samples and only in the case of krill and lamprey was this lipid-rich. As these two albatrosses are of similar size, breed over the same period and feed meals of equivalent weight to their chicks at similar intervals, the difference in the composition of the diet is possibly the most significant mechanism of ecological segregation (in the breeding season). Evidence of the effect of krill shortage in drastically reducing Black-browed Albatross breeding success is presented to support this. The two species have largely non-overlapping winter oceanic ranges which are probably also correlated with the distribution of preferred prey.

120 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present an overview of the knowledge of the soaring flight and strategy of birds, followed by a discussion of control strategies that have been developed for soaring UAVs both in simulations and applications on real platforms.
Abstract: Thermal soaring saves much energy, but flying large distances in this form represents a great challenge for birds, people and unmanned aerial vehicles (UAVs). The solution is to make use of the so-called thermals, which are localized, warmer regions in the atmosphere moving upward with a speed exceeding the descent rate of birds and planes. Saving energy by exploiting the environment more efficiently is an important possibility for autonomous UAVs as well. Successful control strategies have been developed recently for UAVs in simulations and in real applications. This paper first presents an overview of our knowledge of the soaring flight and strategy of birds, followed by a discussion of control strategies that have been developed for soaring UAVs both in simulations and applications on real platforms. To improve the accuracy of the simulation of thermal exploitation strategies we propose a method to take into account the effect of turbulence. Finally, we propose a new GPS-independent control strategy for exploiting thermal updrafts.

81 citations