Searched for: subject%3A%22computational%255C%252Bfluid%255C%252Bdynamics%22
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van der Vooren, J. (author), Huizing, G.H. (author)
A method is discussed for the calculation of inviscid transonic flow about thin airfoils in moderately slow unsteady motion. It is an extension of a method which was developed by Ballhaus and Goorjian of NASA Ames and which is applicable for strictly slow unsteady motions only. The modifications involve extra unsteady terms in the boundary...
report 1980
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Oskam, B. (author)
The viscous flow around multi-component airfoils has been calculated by solving incompressible potential flow and boxindary layer problems iteratively. The potential flow problem is solved by a revised version of the 2D NLR panel method. A model transport equation of turbulent stress is employed to calculate the turbulent boundary layer. The...
report 1980
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van der Vooren, J. (author), Huizing, G.H. (author), van Essen, A. (author)
A calculation method, based upon transonic small perturbation theory, is presented for the transonic flow about a semi-wing. The influence of a body can be simulated by prescribing appropriate transverse velocities in a vertical plane through the wing root. Due to the small perturbation assumption the wing should be thin and have little dihedral...
report 1981
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Lindhout, J.P.F. (author), van den Berg, B. (author), Elsenaar, A. (author)
At the workshop nine participants presented the results of their calculations for a practical test case. The test case deals with the 3D turbulent boundary layer development, including separation, on the root section of a swept wing. The employed calculation methods comprise 3D integral methods as well as field methods. A short description of...
report 1981
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Hoeijmakers, H.W.M. (author)
Characteristics of three second-order and two third-order panel method formulations for the incompressible flow about a flat plate at incidence are investigated. The second order methods employ quadratic representations for the doublet distribution, either based on quadratic B-splines or on a combination of a Taylor series expansion and finite...
report 1981
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Houwink, R. (author)
An outline is given of a first version of the computer programme LTRAFV for coupled unsteady transonic flow/turbxilent boundary layer computations. It is a combination of the LTRAN2-NLR programme and the lagentrainment method of Green. A comparison is made of theoretical and experimental results for the NACA64A006 airfoil with oscillating flap...
report 1981
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Boerstoel, J.W. (author)
The application of multigrid relaxation to transonic potential-flow calculation was investigated. Fully conservative potential flows around aerofoils were taken as test problems. The solution algorithm was based on Newton iteration. In each Newton iteration step, multigrid relaxation was used to calculate correction potentials. It was found that...
report 1981
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van der Vooren, J. (author), van der Kolk, J.T. (author), Slooff, J.W. (author)
A description will be presented of a computer program system that is being used for the prediction of aircraft steady aerodynamic characteristics. Properties of the system are described from two different viewpoints. One is that of the aerodynamic designer, who needs an information system to predict lift, moment and drag characteristics and to...
report 1982
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Slooff, J.W. (author)
Examples are discussed of the application of computational methods in aerodynamic design problems involving interference. Amongst these are: subsonic wing-body, sting support, pylon-nacelle and pylon-store interference, high-lift devices, induced drag minimization through constrained optimization in the Treftz-plane and transonic wing-fuselage...
report 1983
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Labruijere, T.E. (author)
A program system has been developed as a tool for interactive analysis and design of multi-element airfoils in incompressible viscous flow. A global description of the system is given. It involves the application of three computational methods, one for the analysis of viscous flow and one for the analysis of inviscid flow around multi-element...
report 1983
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Boerstoel, J.W. (author)
A survey of numerical methods for the calculation of inviscid Euler flows is presented. This survey has been prepared for AGAKD FDP WGOT: "Test cases for steady inviscid transonic or supersonic flows". The survey is augmented by a short assessment of the usefulness of the methods. For aerodynamic applications, the existing methods are in a...
report 1983
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de Bruin, A.C. (author)
The three dimensional flow field around delta wings with leading-edge vortex flow can be computed with panel methods. However, secondary flow separation may occur on the leeward surface of the wing. The associated free vortex sheet can be modeled in the potential flow calculation method, if the location of the secondary separation is provided by...
report 1983
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Slooff, J.W. (author)
A discussion is given of the physical mechanisms governing the hydrodynamics of sailing yacht keels and the parameters that, through these mechanisms, determine keel performance. It is concluded that due to the presence of the free water surface optimum keel shapes differ from optimum shapes for aircraft wings, a fact that does not seem to have...
report 1984
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Smith, J. (author)
The applicability of two-dimensional flexible solid wall test sections for three-dimensional testing is theoretically investigated for linearized subsonic flow. The method uses known interference velocity distributions along a targer line (derived from a method of images for this particular study). From these, wall shapes are calculated that...
report 1984
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Slooff, J.W. (author)
An overview is provided of computational methods that can be used in solving the design problem of aerodynamics; i.e. the problem of finding the detailed shape of (parts of) configurations of which the gross geometric characteristics have already been determined in a preliminary, overall design process, and that, subject to certain constraints,...
report 1984
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Koppenol, P.J. (author)
A computational method for solving the 3D Euler equations is studied. The method is based upon an upwind flux-difference splitting scheme by Osher, exhibiting an implicit mechanism for numerical viscosity, in connection with an explicit time-marching finite-volume technique. The computer program is developed to run efficiently on both a scalar...
report 1985
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Chen, C.J. (author), Singh, K. (author)
The use of second order closure turbulence model in predicting turbulent flows is known to be more successful than the classical mixing length model. However, it is found that if the turbulence constants are not altered or modified, the second order closure turbulence model is unable to predict satisfactorily f or some flows such as round jet...
report 1985
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van den Dam, R.F. (author)
The central issue discussed in this paper is how a designer may profit from the use of mathematical simulation and optimization techniques. These techniques can be useful tools to support the designer in solving his design problem. The place and the potential of these techniques in the design process, as well as their use by the designer, are...
report 1985
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Boerstoel, J.W. (author)
An analysis of various alternative approaches in grid generation is presented. A grid-generation procedure for complex aircraft configurations could be based on a combination of three subprocesses, . decomposition of the flow domain into about 100 hexahedronal blocks, . trilineair transfinite interpolation to generate initial grid point...
report 1986
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Boerstoel, J.W. (author)
report 1988
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