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 paper, a model based on a spectral representation of the aerodynamic lift force is defined, and the drag and pitching moment are derived using a conditional simulation technique for stochastic processes.
Abstract: The aim of this work is to improve aeroelastic simulation codes by accounting for the unsteady aerodynamic forces that a blade experiences in static stall. A model based on a spectral representation of the aerodynamic lift force is defined. The drag and pitching moment are derived using a conditional simulation technique for stochastic processes. The input data for the model can be collected either from measurements or from numerical results from a Computational Fluid Dynamics code for airfoil sections at constant angles of attack. An analysis of such data is provided, which helps to determine the characteristics of stall. The model is applied to wind turbine rotor cases, including the stand still condition, and results are compared to experimental data. Copyright © 2009 John Wiley & Sons, Ltd.
20 citations
10 May 1949
TL;DR: The results of tests of 22 triangular wings, representing two leading-edge shapes for each of 11 apex angles, at Mach numbers 162, 192, and 140 are presented and compared with theory.
Abstract: The results of tests of 22 triangular wings, representing two leading-edge shapes for each of 11 apex angles, at Mach numbers 162, 192, and 140 are presented and compared with theory All wings have a common thickness ratio of 8 percent and a common maximum-thickness point at 18 percent chord Lift, drag, and pitching moment are given for all wings at each Mach number The relation of transition in the boundary layer, shocks on the wing surfaces, and characteristics of the pressure distributions is discussed for several wings
20 citations
TL;DR: In this article, a theory for the unsteady aerodynamics of deformable thin airfoils is presented, which extends the theory developed by Theodorsen and Garrick, which is restricted to rigid body motion.
Abstract: The paper presents a theory for the unsteady aerodynamics of deformable thin airfoils. It extends the theory developed by Theodorsen and Garrick, which is restricted to rigid body motion. Frequency-domain lift, pitching moment, and thrust expressions are derived for an airfoil undergoing harmonic oscillations and deformation in the form of the Chebychev polynomials. The first two polynomials give the rigid body motion, whereas the rest represent the deformation. The results are verified with the time-domain unsteady aerodynamic theory of Peters. Numerical results are presented for several combinations of airfoil motion, which identify various possibilities for thrust generation using a deformable airfoil.
20 citations
01 Jan 1983
TL;DR: In this paper, a two-dimensional wind tunnel test has been performed on a small circulation control airfoil section equipped with trailing edge blowing, which was mounted in the NASA-Ames 2 x 2 ft transonic wind tunnel and tested at speeds up to free-stream Mach equals 0.75 for a range of incidences.
Abstract: A two-dimensional wind tunnel test has been performed on a small circulation control airfoil section equipped with trailing edge blowing. The model was mounted in the NASA-Ames 2 x 2 ft transonic wind tunnel and tested at speeds up to free-stream Mach equals 0.75 for a range of incidences. Jet pressure ratios up to 3 (relative to tunnel static conditions) were evaluated together with the effects of Reynolds number. Normal force and pitching moment coefficients were calculated from surface pressures using a Scanivalve pressure measuring system. Drag force coefficients were calculated from wake rake pressures. The results obtained indicated that this airfoil was capable of producing useful lift at high subsonic Mach numbers. Some changes in the stall characteristics were apparent at above free-stream Mach equals 0.4 and some dependence between lift augmentation and incidence was observed. There also appeared to be a significant Reynolds number effect on the airfoil drag performance.
20 citations
10 Aug 2009
TL;DR: In this article, the authors developed an aerodynamic model and a dynamic model of a morphing ying wing aircraft, including realistic aerodynamic forces, consisting of lift, drag, and pitching moment about the leading edge, calculated using a constant strength source doublet panel method.
Abstract: Morphing aircraft are envisioned to have multirole capability where the ability to change shape allows for adaptation to a changing mission environment. In order to calculate the properties of many wing congurations eciently and rapidly, a model of a morphing aircraft is needed. This paper develops an aerodynamic model and a dynamic model of a morphing ying wing aircraft. The dynamic model includes realistic aerodynamic forces, consisting of lift, drag, and pitching moment about the leading edge, calculated using a constant strength source doublet panel method. The panel method allows for the calculation of aerodynamic forces due to large scale shape changing eects. The aerodynamic model allows for asymmetric congurations in order to generate rolling and yawing moments. The dynamic model calculates state information for the morphing wing based on the aerodynamic forces from the panel method. The model allows for multiple shape changing degrees-of-freedom for the wing, including thickness, sweep, dihedral angle, and chord length. Results show the model provides a versatile and computationally ecient tool for
20 citations