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Vogels, M.E.S. (author)
For flow simulation around (parts of) aerospace vehicles, aerospace industry needs CFD software. For users in industry, not only the functionality of the software is relevant. Timely availability and cost of the first version and later versions are other relevant factors. These factors are represented in the software characteristics timeliness,...
report 1997
document
Vreeburg, J.P.B. (author)
The representation of the acceleration field on a rigid body contains as parameters its angular rate and acceleration vectors plus the acceleration vector at a single point of the body. A linear accelerometer measures a local component of the field. From the response of different accelerometers, three quadratic forms in the angular rate of the...
report 1995
document
van der Ven, H. (author)
In this TP a family of filters for Large Eddy Simulation with nonuniform filter widths is constructed that commute with differentiation up to any given order.
report 1994
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Velldman, A.E.P. (author), Lindhout, J.P.F. (author), de Boer, E. (author)
A description is given of VISIAN - a simulation method for 2-D viscous flows with strong viscous-inviscid interaction. The mathematical mode and the numerical algorithm are presented. VISIAN has been coupled with the inviscid-flow solver TRAPS. Results are shown for a number of airfoils; a comparison is made with results from other computations...
report 1988
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Labrujère, T.E. (author), Maarsingh, R.A. (author), Smith, J. (author)
Measurements on a simple aircraft model in both an appropriately sized and a relatively large, low-speed, solid-wall test section were used to analyse the accuracy and consistency of measured-boundary-condition (MBC) methods. For completeness, the classical method of images, with two different correction procedures, was also analysed. For the...
report 1988
document
Kuijpers, E.A. (author)
report 1987
document
Kuijpers, E.A. (author)
Existing robot vision algorithms are evaluated for application in space for proximity extraction using one camera. Lighting conditions and image formation differ from earth conditions which have implications. An algorithm is derived which is based on the use of run coding, tracking and a least mean error method. Problems concerning hardware...
report 1987
document
Moek, G. (author)
Expressions are derived from which confidence regions for the parameters of three specific software reliability models can be computed. These expressions are based on the asymptotic probability distribution of the maximum likelihood estimator. Some numerical results of point estimates as well as confidence regions are given, based on simulated...
report 1987
document
Roefs, H.F.A. (author), Monkel, A. (author)
Project CADISS has produced an elegant breadboard of a system for compression (and -if required- decompression) of signals generated by imaging sensors on-board scientific satellites. The performance, specifications and physical characteristics of CADISS are the result of trade-offs on function (algorithms), technology, through-put speed and...
report 1987
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Guelman, M. (author)
The mathematical model of a space based manipulator arm with a rate controlled end effector is defined and the recursive algorithms for the computation of the basic djmamic functions are formulated. A digital simulation of this system is implemented and preliminary results are presented. Actual running times for the simulation In a VAX 750...
report 1986
document
Hounjet, M.H.L. (author)
A new method ARSPSC is described for the calculation of steady and time-linearized unsteady subsonic potential flow about complex 2-D and 3-D configurations. The method belongs to the category of the so-called panel methods. Applications have been made to a 2-D oscillating flat plate, a 2-D multi-component airfoil with oscillating flap and a 3-D...
report 1986
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Hogendoorn, R.A. (author)
Non-specialist users of data compression often encounter difficulties with the selection of an algorithm, suited for their application. This report tries to facilitate this task by providing the necessary information about the algorithms. Four established, at the National Aerospace Laboratory available algorithms were selected for this study: -...
report 1986
document
Versteeg, M.H.J.B. (author)
This report describes the results of a feasibility study into some aspects of a proposed METEOSAT image data compression unit. The study was performed to support the preparation of a proposal for ESOC. For the considered algorithms (ESTEC 1 & MEANDER 1) an estimate of the needed processing power based on the 68000 instruction set was made. This...
report 1986
document
Blom, H.A.P. (author)
The general setup of the evaluation of a radar tracking algorithm in a civil ATC-system has been considered from an operational point of view. Both the present and the potential future use of trackdate has been taken in account. The result is a method to evaluate trackers for ATC on the basis of live-traffic data, under the assumption that a...
report 1986
document
Hoogendoorn, R.A. (author)
Computations in numerical fluid dynamics create large sets of data. Transmission of these datasets requires a high speed communication link or, alternatively, the use of data compression techniques. This report describes the results of a study to the applicability of data compression techniques. An algorithm is designed that yields favourable...
report 1986
document
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
document
Lof, C.J. (author)
An application of linear elastic fracture mechanics to 3-dimensional crack growth prediction was developed in two phases. In the first phase finite element techniques for accurate stress intensity (S.I.) calculation were evaluated and the Virtual Crack Extension (V.C.E.)-method was selected for further work. In the second phase the process of...
report 1981
document
Vaatstra, W. (author), Veldman, A.E.P. (author), van der Vooren, J. (author)
The method of Glowinski, Periaux and Pironneau for the calculation of transonic flow, which is based on the constrained minimization of a cost function, is critically evaluated for a case in which the transonic small perturbation equation is used. The resulting minimization problem is discretized in finite element form and solved using a...
report 1980
document
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
document
van Woerkom, P.Th.L.M. (author), Sonnenschein, F.J. (author)
The study deals with the rotational motion of a spin-stabilized spacecraft equipped with a V-slit sun sensor and the X-slit ESA starmapper. Assuming complete absence of an a priori attitude estimate, it is required to produce a rough estimate of the spacecraft attitude motion. It was assumed that sensor misalignments, external torques and...
report 1979
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