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- Petit, H.A.H. (author), Bosch, P. van den (author) report 1997
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Sijtsma, P. (author)A theory is presented to calculate acoustic modes in a circular flow duct lined with porous material. The porous material is divided into annular segments by a rigid structure, which prevents axial sound propagation from one segment into the other. Single modes cannot exist in such a configuration, but it is shown that approximate solutions of...report 1996
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- Petit, H.A.H. (author), Bosch, P. van den (author), Gent, M.R.A. van (author) report 1994
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Van Swol, F.J.P. (author)As a result of recent floods caused by mountain rivers, more insight in the morphological processes concerning sedimentation problems and the bottom roughness to predict the expected water levels, is necessary to preclude future catastrophes. The aim of the study is to obtain more insight in the prediction of bottom roughness for situations...master thesis 1993
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- Sluys, L.J. (author), De Borst, R. (author), Muhlhaus, H.B. (author) journal article 1993
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Noback, R. (author)The Deterministic Power-Spectral-Density method can be derived from the Design Envelope Analysis of the continuous P.S.D.-method. It provides a method to determine a deterministic function that gives a maximum response equal to the P.S.D.-design load for linear systems. The P.S.D.-design load is undefined for nonlinear systems. In this report a ...report 1992
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Noback, N. (author)The Deterministic Power-Spectral-Density-method has been derived directly from the continuous P.S.D.-method. It can be regarded as a "translation" from the frequency domain to the space or time domain. The critical gust profile, giving maximum response, is obtained directly. The D.P.S.D.-method gives the same results as the continuous P.S.D.-...report 1992
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- Sluys, L.J. (author), De Borst, R. (author) journal article 1992
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- Van der Beek, C.G.A. (author) doctoral thesis 1989
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- Khalil, M. (author) doctoral thesis 1989
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Labrujère, T.E. (author)A method is described, which is the result of further work on a measured boundary condition method developed at NLR, aiming at on-line application. The method requires a minimum of measured tunnel-wall pressures and applies a fast algorithm for the calculation of the wall interference. Some numerical test results are discussed.report 1989
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Schippers, H. (author)A description is given of TULIPS - a method for Transonic Unsteady Lifting Inviscid Potential-flow Simulation. The Mathematical formulation and the numerical approach are presented for flow about oscillating airfoils. TULIPS is based on the numerical integration of the unsteady full-potential equation in generalized coordinates. The equation is...report 1988
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van Beek, C.M. (author)The application of a boundary integral or "panel" method to duct flows is described. The method is capable of computing the three dimensional, steady state, subsonic, linearized (Prandtl-Glauert) potential flow about general configurations. The method is characterized by the application of a Dirichlet boundary condition and of "compressible"...report 1987
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Noback, R. (author)This report gives an outline of the method to generate equal probility design load conditions. The various steps are described.report 1985
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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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Rienstra, S.W. (author)A study is made of sound propagation through axially varying ducts with mean flow. Several analytical and numerical approaches are considered, and discussed with respect to their possibilities and limitations. Two new analytical theories, relevant for low and for high frequencies, are worked out in some detail. A fortuitously available *)...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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Dekker, G.J. (author), van der Wilt, M. (author), van den Bosch, F.J. (author)Cost estimation of software development and control of the cost during the development, are difficult due to the lack of useful cost figures from previous projects, and consequently due to the lack of an accurate cost estimation and management method. This report describes the results of the first phase of a study to develop a software cost...report 1981
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Laan, J.N. (author)It is concluded from this limited analytic study of pure tone sound suppression in a cylindrical duct with uniform flow, based on the mode matching technique, that the optimum of the liner impedance heavily depends on the source distribution and also on the length of the duct.report 1981
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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