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Airfoil

About: Airfoil is a research topic. Over the lifetime, 24696 publications have been published within this topic receiving 337709 citations. The topic is also known as: aerofoil & wing section.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the dominant role of the passage vortex, which develops from the singular separation of the inlet boundary layer, in determining heat transfer at the endwall and at certain regions of the airfoil surface is illustrated.
Abstract: Local rates of heat transfer on the endwall, suction, and pressure surfaces of a large scale turbine blade cascade were measured for two inlet boundary layer thicknesses and for a Reynolds number typical of gas turbine engine operation. The accuracy and spatial resolution of the measurements were sufficient to reveal local variations of heat transfer associated with distinct flow regimes and with regions of strong three-dimensional flow. Pertinent results of surface flow visualization and pressure measurements are included. The dominant role of the passage vortex, which develops from the singular separation of the inlet boundary layer, in determining heat transfer at the endwall and at certain regions of the airfoil surface is illustrated. Heat transfer on the passage surfaces is discussed and measurements at airfoil midspan are compared with current finite difference prediction methods.

201 citations

Journal ArticleDOI
TL;DR: In this paper, a quasi-3D Navier-Stokes model is proposed for wind turbine blades, which is derived from the 3D primitive variable Navier Stokes equations written in cylindrical coordinates in the rotating frame of reference.
Abstract: Three-dimensional and rotational viscous effects on wind turbine blades are investigated by means of a quasi-3D Navier-Stokes model. The governing equations of the model are derived from the 3-D primitive variable Navier-Stokes equations written in cylindrical coordinates in the rotating frame of reference. The latter are integrated along the radial direction and certain assumptions are made for the mean values of the radial derivatives. The validity of these assumptions is cross-checked through fully 3-D Navier-Stokes calculations. The resulting quasi-3D model suggests that three-dimensional and rotational effects be strongly related to the local chord by radii ratio and the twist angle. The equations of the model are numerically integrated by means of a pressure correction algorithm. Both laminar and turbulent flow simulations are performed. The former is used for identifying the physical mechanism associated with the 3-D and rotational effects, while the latter for establishing semiempirical correction laws for the load coefficients, based on 2-D airfoil data. Comparing calculated and measured power curves of a stall controlled wind turbine, it is shown that the suggested correction laws may improve significantly the accuracy of the predictions.

201 citations

21 Dec 1977
TL;DR: In this paper, an experimental analysis of high-subsonic and transonic flow on a conventional airfoil with oscillating flap and a supercritical airframe oscillating in pitch is presented, where the interaction between the steady and unsteady flow fields, the periodical motion of the shock waves and their contribution to the overall unstrainy airloads are discussed.
Abstract: Exploratory wind-tunnel experiments in high-subsonic and transonic flow on a conventional airfoil with oscillating flap and a supercritical airfoil oscillating in pitch are described. In the analysis of the experimental results, emphasis is placed upon the typical aspects of transonic flow, namely the interaction between the steady and unsteady flow fields, the periodical motion of the shock waves and their contribution to the overall unsteady airloads. Special attention is paid to the behaviour of the supercritical airfoil in its "shock-free" design condition. Moreover, it is discussed to what extent linearization of the unsteady transonic flow problem is allowed if the unsteady field is considered as a small perturbation superimposed upon a given mean steady-flow field. Finally, the current status of unsteady transonic flow theory is reviewed and the present test data are used to evaluate some of the recently developed calculation methods.

199 citations

Journal ArticleDOI
TL;DR: In this paper, a computer code, LTRAN2, has been constructed that efficiently computes low-frequency unsteady transonic flows about airfoils in motion.
Abstract: A computer code, LTRAN2, has been constructed that efficiently computes low-frequency unsteady transonic flows about airfoils in motion. The code solves the two-dimensional, nonlinear, low-frequency, smalldisturbance equation by an alternating-direction implicit (ADI) algorithm. The underlying theory of the governing equation and the construction of the solution algorithm are discussed. As a check on the code, solutions computed for the linear low-frequency small-disturbance equation are compared with known answers from linear theory. Then nonlinear results are presented, and Tijdeman's experimental observations of shock wave motions resulting from airfoil flap oscillations are qualitatively reproduced computationally. These computations compare favorably with those of Magnus and Yoshihara and are obtained in substantially less computer time.

198 citations

Journal ArticleDOI
TL;DR: In this paper, a space-time discontinuous Galerkin finite element method for the compressible Navier-Stokes equations is presented, which allows local grid adaptation as well as moving and deforming boundaries.

197 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,083
20221,871
2021923
2020979
20191,097
20181,002