Topic
Pitching moment
About: Pitching moment is a research topic. Over the lifetime, 3213 publications have been published within this topic receiving 38721 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, a simulation of an articulated model rotor in hover and forward flight was carried out to assess the effects of blade dynamics and elasticity on numerical results, and the results showed that the aeroelastic results were in much better agreement with the measurements than those obtained from rigid-blade simulations with prescribed articulation.
Abstract: Aeroelastic Reynolds-averaged Navier‐Stokes and Euler computations are presented for an articulated model rotor in hover and forward flight. Comparative rigid-blade simulations are carried out to assess the effects of blade dynamics and elasticity on the numerical results. The INROT flow solver operates on deformable structured overset grids and can be tightly coupled with a finite element model of the rotor blade structure (DYNROT) based on Timoshenko beam theory. The order of time accuracy of fluid and structure modules is maintained in the overall analysis by an appropriate staggered coupling scheme. At the investigated thrust setting, global hover performance values computed by the coupled fully turbulent Navier‐Stokes analysis agree fairly well with available experimental data. In forward flight, the aeroelastic results are in much better agreement with the measurements than those obtained from rigid-blade simulations with prescribed articulation. Apart from superior rotor power predicition, the local pitching moment coefficients computed by the viscous analysis are found to correlate better with wind-tunnel data than the corresponding Euler output.
59 citations
01 Jan 1937
TL;DR: In this paper, the authors present tables and charts for use in determining the characteristics of tapered wings, including span lift distribution, induced-angle-of-attack distribution, lift-curve slope, angle of zero lift, induced drag, aerodynamic-center position, and the pitching moment about the aerodynamic center.
Abstract: This report presents tables and charts for use in determining the characteristics of tapered wings. Theoretical factors are given from which the following characteristics of tapered wings may be found: the span lift distribution, the induced-angle-of attack distribution, the lift-curve slope, the angle of zero lift, the induced drag, the aerodynamic-center position, and the pitching moment about the aerodynamic center.
58 citations
01 Sep 1972
TL;DR: In this paper, an investigation was conducted to determine the flow field and aerodynamic effects of leading edge serrations on a two-dimensional airfoil at a Mach number of 0.13.
Abstract: An investigation was conducted to determine the flow field and aerodynamic effects of leading-edge serrations on a two-dimensional airfoil at a Mach number of 0.13. The model was a NACA 66-012 airfoil section with a 0.76 m (30 in.) chord, 1.02 m (40 in.) span, and floor and end plates. It was mounted in the Ames 7- by 10-Foot Wind Tunnel. Serrated brass strips of various sizes and shapes were attached to the model in the region of the leading edge. Force and moment data, and photographs of tuft patterns and of oil flow patterns are presented. Results indicated that the smaller serrations, when properly placed on the airfoil, created vortices that increased maximum lift and angle of attack for maximum lift. The drag of the airfoil was not increased by these serrations at airfoil angles of attack near zero and was decreased at large angles of attack. Important parameters were serration size, position on the airfoil, and spacing between serrations.
58 citations
TL;DR: In this paper, the effects of blade vibration on the aerodynamic load on a large-scale HAWT blade during its operating lifetime were investigated and an aerodynamic model based on the Blade Element Momentum (BEM) theory and the Beddoes-Leishman (B-L) dynamic stall model was proposed.
58 citations
28 Jun 2010
TL;DR: In this article, the flight maneuver of perching is abstracted as a linear pitch ramp, with and without a deceleration in the free-stream direction, and an experimental survey of reduced frequency and pivot point for a range of flat plate pitching cases from 0o to 90o.
Abstract: The flight maneuver of perching is abstracted as a linear pitch ramp, with and without a deceleration in the free-stream direction. We consider, first, experimental-computational comparison for flowfield and aerodynamic force coefficients for an SD7003 airfoil pitching from α = 0o to 45o; and second, an experimental survey of reduced frequency and pivot point for a range of flat plate pitching cases from 0o to 90o. The computational approach is 3D Large Eddy Simulation, and the experimental approach is by three degree of freedom electric motion-rig in a water tunnel. Accurate flowfield resolution in deep-stall is seen to require a large spanwise extent of computational domain. Meanwhile, experiment can be plagued with blockage, and dynamic blockage was seen to behave differently than static blockage. Even very low reduced frequencies of motion give lift overshoot beyond static stall, but comparatively large frequencies are necessary before the lift curve slope changes, either due to rate effects or acceleration effects. Moving the pitch pivot point further aft tends to attenuate both lift and drag production, and pitching about the three-quarter chord point cancels the rate-effect, in agreement with quasi-steady linear airfoil theory. Surprisingly, the aerodynamic coefficient history differs little between cases with and without streamwise deceleration, except towards the very end of the motion. The implication is that perching-type of ground tests or computations can be adequately conducted in a steady free-stream.
58 citations