Topic
Lift-induced drag
About: Lift-induced drag is a research topic. Over the lifetime, 2861 publications have been published within this topic receiving 41094 citations.
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01 Jan 1990
TL;DR: In this paper, the concept of convex aerodynamic surface curvature was used in axisymmetric bodies to determine whether the viscous component of total drag is reduced by applying the curvature.
Abstract: Experiments have indicated that for certain convex aerodynamic surface curvature ratios, wall-shear stresses remain low over considerable streamwide distances even after curvature is removed The research whose progress is presently evaluated was first suggested by Bushnell (1983), who proposed that the convex-surface curvature be used in axisymmetric bodies to ascertain whether the viscous component of total drag is reduced Attention is given to the evolution of the concept's implementation in an axisymmetric nose-body combination for passive viscous drag reduction
11 citations
01 Mar 1986
TL;DR: WAVDRAG as discussed by the authors is a numerical model of aircraft used throughout design process from concept to manufacturing, which incorporates extended geometric input capabilities to permit use of more accurate mathematical model and calculates supersonic zero-lift wave drag of complex aircraft configurations.
Abstract: WAVDRAG calculates supersonic zero-lift wave drag of complex aircraft configurations. Numerical model of aircraft used throughout design process from concept to manufacturing. Incorporates extended geometric input capabilities to permit use of more accurate mathematical model. Engineer defines aircraft components as fusiform or nonfusiform in terms of traditional parallel contours or nonintersecting contours in any direction. Laterally asymmetric configurations simulated. WAVDRAG calculates total drag and wave-drag coefficient of specified aircraft configuration.
11 citations
Patent•
20 Sep 1994
TL;DR: A drag structure for a fishing reel comprising a drag assembly, and a drag control element for contacting said drag assembly to produce a drag force is described in this paper, where the angler can switch between an operational position in which to vary the drag force and an in-operational position where not to produce the force.
Abstract: A drag structure for a fishing reel comprising a drag assembly, and a drag control element for contacting said drag assembly to produce a drag force. The drag control element is adjustably movable toward and away from said drag assembly and switchable between an operational position in which to vary the drag force and an inoperational position in which not to produce the drag force. The drag control element includes means for informing the angler that the drag control element is switched to the inoperational position.
11 citations
03 Apr 2007-Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems
TL;DR: In this paper, a piecewise linear model (PLM) is used to estimate the forcing frequency spectrum and interpolate or extrapolate the model to provide estimates of the spectrum at different points in the parameter space.
Abstract: A method is proposed to estimate the flow-induced drag on the actuator arm inside a hard disk drive. Typically, drag forces and moments on the actuator are computed as part of a computational fluid dynamics (CFD) solution of the flow field in the entire drive. Unidirectional coupling from the flow to the structure is then imposed to determine the structural response of the arm to the flow induced forcing. The methodology proposed here aims to reduce the simulation time associated with the flow calculations by directly estimating the forcing functions. The approach involves fitting a piecewise linear model (PLM) to the forcing frequency spectrum and interpolating or extrapolating the model to provide estimates of the spectrum at different points in the parameter space. A simple guideline for the formulation of such models is the conservation of energy between the CFD and PLM spectrum. Numerical experiments show that the linear models predict the behavior of arm to within 3% accuracy of the full CFD solution. The proposed technique is applied to two parameters: the disk RPM and the radial position of the arm. Clear trends are manifested for both parameters, making it possible to use this method to estimate forcing functions for a range of disk speeds and radial positions of the arm. This technique opens up the possibility of flow related design or optimization, which was previously thought to be prohibitively expensive.
11 citations
01 Sep 1988
TL;DR: In this article, a suction-based method for the laminarization of highly-swept supersonic wings at cruise Mach numbers in the 2.0-2.5 range was evaluated.
Abstract: An evaluation is made of a suction-based method for the laminarization of highly-swept supersonic wings at cruise Mach numbers in the 2.0-2.5 range, in the interest of the reduction of wave drag due to lift. The laminar boundary layer development, as well as Tollmien-Schlichting and crossflow instabilities, have been analyzed for the case of an X66 supercritical airfoil at 60 and 72 deg sweep, for Mach numbers of 1.56 and 2.52, respectively. Strong suction is found to be needed at the front part of the upper surface and both the upper and lower rear pressure-rise areas.
11 citations