Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 56
Book Description
Multi-element Airfoil Viscous-inviscid Interactions
Author: The Viscous Transonic Flow Over Two-Element Airfoil Systems
Author: G. VolpePublisher:
ISBN:
Category :
Languages : en
Pages : 49
Book Description
A numerical procedure has been developed to compute the transonic viscous-inviscid interacting flow field about airfoils with leading edge slats or trailing edge flaps. The inviscid theory utilizes conformal mappings in a full potential flow formulation, with analytic removal of singularities and a mixed flow relaxation procedure. The turbulent boundary layer is computed with methods based on a turbulent kinetic energy formulation and is coupled to the inviscid flow using surface source flow boundary conditions. Semiempirical methods are used to compute local strong interaction regions occurring in the vicinity of shock waves, trailing edges, and to account for flow separation. Our results are in good agreement with existing wind tunnel data for several typical two-element airfoil configurations. (Author).
Computation of Viscous-Inviscid Interactions
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 531
Book Description
This symposium was consequently organized to review the search for coupling procedures. It appears that the situation is quite satisfactory for 2D flows. Very good correlations can be found between the computational results and the experiments provided that the methods include the wake displacement and curvature effects, and adequate treatment of the trailing edge region and of the shock boundary layer interactions. If so, useful and reliable tools are available for engineering purposes. However, the agreement generally deteriorates with the extension of separated regions or when the shock intensity increases and further improvements are still needed, for example, for single or multielement airfoils near maximum lift or at high Mach numbers. In addition it must be stressed that the quality and the accuracy of the experimental data become questionable as the capability of the computational methods to adequately describe more and more complex situations increases. Therefore precise and reliable code validation requires more and more well documented benchmark data. For 3D configurations, the work is much less advanced; only a few studies have been made and a lot of work has still to be done, especially in the transonic regime. However, the first results obtained using the ideas which have proven to be efficient in 2D are encouraging. The problem of separation with formation and rolling-up of vortex sheets which is specific to 3D flows is of primary importance and the studies already made on this subject will have to be pursued and extended in the compressible and transonic regime. Finally, it has been recorded that the need for detailed benchmark experiments is even greater in 3D than in 2D.
A Viscous/potential Flow Interaction Analysis Method for Multi-element Infinite Swept Wings
Author: F. A. DvorakPublisher:
ISBN:
Category : Aerodynamic load
Languages : en
Pages : 100
Book Description
An analysis method and computer program have been developed for the calculation of the viscosity dependent aerodynamic characteristics of multi-element infinite swept wings in incompressible flow. The wing configuration consisting at the most of a slat, a main element and double slotted flap is represented in the method by a large number of panels. The inviscid pressure distribution about a given configuration in the normal chord direction is determined using a two dimensional potential flow program employing a vortex lattice technique. The boundary layer development over each individual element of the high lift configuration is determined using either integral or finite difference boundary layer techniques. A source distribution is then determined as a function of the calculated boundary layer displacement thickness and pressure distributions. This source distribution is included in the second calculation of the potential flow about the configuration. Once the solution has converged (usually after 2-5 iterations between the potential flow and boundary layer calculations) lift, drag, and pitching moments can be determined as functions of Reynolds number.
Scientific and Technical Aerospace Reports
Author: A Viscous-inviscid Interaction Study Using Complementary RANS Equations
Author: Kunho KimA Three-dimensional Viscous/potential Flow Interaction Analysis Method for Multi-element Wings
Author: A Viscous Potential Flow Interaction Analysis Method for Multi-element Infinite Swept Wings, Volume 2
Author: Studies of Vortex Dominated Flows
Author: M.Y. HussainiPublisher: Springer Science & Business Media
ISBN: 1461246784
Category : Science
Languages : en
Pages : 367
Book Description
From the astrophysical scale of a swirling spiral galaxy, through the geophysical scale of a hurricane, down to the subatomic scale of elementary particles, vortical motion and vortex dynamics have played a profound role in our understanding of the physical world. Kuchemann referred to vortex dynamics as "the sinews and muscles of fluid motion. " In order to update our understanding of vortex dominated flows, NASA Langley Research Center and the Institute for Computer Applications in Science and Engineering (ICASE) conducted a workshop during July 9-11, 1985. The subject was broadly divided into five overlapping topics vortex dynamics, vortex breakdown, massive separation, vortex shedding from sharp leading edges and conically separated flows. Some of the experts in each of these areas were invited to provide an overview of the subject. This volume is the proceedings of the workshop and contains the latest, theoretical, numerical, and experimental work in the above-mentioned areas. Leibovich, Widnall, Moore and Sirovich discussed topics on the fundamentals of vortex dynamics, while Keller and Hafez treated the problem of vortex break down phenomena; the contributions of Smith, Davis and LeBalleur were in the area of massive separation and inviscid-viscous interactions, while those of Cheng, Hoeijmakers and Munnan dealt with sharp-leading-edge vortex flows; and Fiddes and Marconi represented the category of conical separated flows.
Aeronautical Engineering
Author: Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 932
Book Description
A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).