Proceedings ArticleDOI
Drag-reduction characteristics of aft-swept wing tips
TLDR
In this paper, a study conducted to analyze the potential aerodynamic improvements which can be obtained with aft-swept wing tips at subsonic speeds is presented, which demonstrate that substantial induced-drag improvements could be obtained through the adoption of plan-form shapes with highly-tapered aftswept tips.Abstract:
Results are presented of a study conducted to analyze the potential aerodynamic improvements which can be obtained with aft-swept wing tips at subsonic speeds. A review and summary of previous swept-tip applications and studies are given. Additionally, the through evolution optimized tail-fin shapes of fast-cruising aquatic animals are examined as well as the wing planform shapes of sea birds. These superior long-distance travellers both display lifting-surface planform shapes with increased leading-edge sweep towards the tip. These observations and analytical results obtained with a nonlinear surface-panel method demonstrate that substantial induced-drag improvements can be obtained through the adoption of planform shapes with highly-tapered aft-swept tips.read more
Citations
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Dissertation
A time-domain panel method for oscillating propulsors with both chordwise and spanwise flexibility
TL;DR: In this article, a time domain panel method was formulated and a computer program package, OSFBEM, was developed to evaluate the propulsive performance of oscillating propulsors.
Journal ArticleDOI
Kinematics of diving Atlantic Puffins (Fratercula arctica, L.): Evidence for an active upstroke.
TL;DR: The results show that the Atlantic puffin can use an active upstroke during diving, in contradiction to previous data, and it is suggested that the partly folded wings of diving puffins might act as efficient aft-swept wingtips, reducing the induced drag and increasing the lift-to-drag ratio.
Journal ArticleDOI
Hydrodynamic characteristics of a lunate shape oscillating propulsor
Pengfei Liu,Neil Bose +1 more
TL;DR: In this paper, a potential flow-based time domain panel method was formulated to predict the performance of a lunate and rectangular planform in large amplitude, unsteady motion, and the results showed that the lunate tail gave higher propulsive efficiency than the rectangular tail.
Journal ArticleDOI
Winglets on low-aspect-ratio wings
John M. Kuhlman,Paul Liaw +1 more
TL;DR: In this article, both wing-winglet and wing-alone design geometries were derived from a linear-theory, minimum induced drag design methodology and relative performance was evaluated with a nonlinear extended small disturbance potential flow analysis code.
References
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Journal ArticleDOI
Aquatic animal propulsion of high hydromechanical efficiency
TL;DR: In this paper, a preliminary quantitative analysis of how a series of modifications of that basic undulatory mode, found in the vertebrates (and especially in the fishes), tends to improve speed and hydromechanical efficiency.
Journal ArticleDOI
Hydromechanics of swimming propulsion. part 1. Swimming of a two-dimensional flexible plate at variable forward speeds in an inviscid fluid
TL;DR: In this paper, the main features of this undulatory mode of propulsion are discussed for the case of large Reynolds number, based on the principle of energy conservation, and the general problem of a two-dimensional flexible plate, swimming at arbitrary, unsteady forward speeds, is solved by applying the linearized inviscid flow theory.
ReportDOI
Calculation of potential flow about arbitrary three-dimensional lifting bodies
TL;DR: In this paper, a method for calculating potential flow about arbitrary lifting three-dimensional bodies without the approximations inherent in lifting-surface theories is presented, and a considerable number of calculated results for various configurations are presented to illustrate the power and scope of the method.
Journal ArticleDOI
Prediction of Subsonic Aerodynamic Characteristics: A Case for Low-Order Panel Methods
TL;DR: In this paper, a low-order panel method is presented for the calculation of subsonic aerodynamic characteristics of general configurations, based on piecewise constant doublet and source singularities.