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de Pagter, P.J. (author), Renes, J.J. (author)
This report describes the results of a feasibility study on image data compression using spline approximation and image segmentation, with emphasis on earth observation applications. The main subjects dealt with, are: the data compression method, implementation aspects, the test software and test results. It appears that a reduction factor of 5...
report 1985
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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
document
Loeve, W. (author), van den Dam, R.F. (author)
The NLR in the Netherlands renders scientific support and technical assistance for the design and operation of aircraft and spacecraft. The approach of NLR can be characterized by integration of experimental and theoretical investigations. For this an integrated computer and terminal network has been developed that links both NLR laboratory...
report 1983
document
van der Laan, J.M. (author)
A measuring system is described for detection and analyses of aircraft wake vortices in the approach zone of a runway. This system consists of propeller anemometers, a data-acquisition unit, a quick-look monitor and a NOVA minicomputer with a real-time vortex detection program. A short description of aircraft wake vortices is also given. Some...
report 1982
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van den Dam, R.F. (author)
An interactive computer program system has been developed which provides induced-drag analysis, optimization and configuration-design capabilities. The program system employs subsonic far-field (Trefftzplane) analysis, and novel mathematical formulations of the constrained optimization problems which are based on calculus of variations. The...
report 1982
document
Vlieger, H. (author)
This report presents results of residual strength calculations, carried out on cracked panel configurations of various designs and provided with bonded stiffeners. The calculations were carried out using the computer program BOND. The results of these calculations are compared with results of residual strength tests, performed on panels of...
report 1983
document
Richmond, M.J. (author), de Koning, A.U. (author)
Utilising the NLR Stripyield cycle-by-cycle fatigue crack growth model a basic description of the time dependent effects associated with periods of constant load level has been added to model Fatigue-Creep interactions. An outline of the basic Creep model is given along with flow diagrams of the sub programs added to the Stripyield model. Other...
report 1993
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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
document
van der Linden, H.H. (author)
The GARTEUR Group of Responsables for Structures and Materials identified the need for an evaluation of fatigue crack propagation models. This resulted in a collaborative GARTEUR activity in which 13 variations of the F-27 transport spectrum were evaluated by 7 institutes and companies using in total 13 crack propagation prediction methods and...
report 1983
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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
document
van Egmond, J.A. (author), van den Berg, B. (author), Labrujere, T.E. (author)
At NLR a system for the computational design on multi-element airfoil has been developed. This design system solves the inverse aerodynamic problem in an approximate way. A priori specified aerodynamic requirements (surface pressure distribution) and geometric requirements are minimized in a least-squares way, introducing weight factors to...
report 1983
document
Lowak, H. (author), de Jonge, J.B. (author), Franz, J. (author), Schutz, D. (author)
The Transport Wing Standard programme (TWIST) published in March 1973 is considered to be representative for the load history of the wing root of transport aircraft. A description of the shortened version of this load programme called MINITWIST is given in the present report. In all cases where testing time is a prohibitive factor to use TWIST,...
report 1979
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Traas, C.R. (author), Moek, G. (author)
The attitude measurement data of the ESA geosynchronous spacecraft METEOSAT have been analyzed using an adaptive recursive filtering technique developed at NLR. The mathematical models of spacecraft dynamics and sensors have been kept very simple. Modelling errors are such that, without adaptive feed-back, strong divergence of the filtering...
report 1978
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Vink, W.J. (author), de Jonge, J.B. (author)
The present report is part of a "Manual" on aircraft loads, that is being prepared by NLR. It contains a computer program, to be used in combination with "MATLAB4 for Windows" (Student Edition) software, to study aircraft loading due to turbulence. It includes a simple aircraft response model with two rigid and three flexible symmetric degrees...
report 1997
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Olthoff, J. (author)
This report provides an inventory of computer programs for composite materials which are owned by or known to the members of the NFK-TVK action group. The programs are divided in four groups: general laminate theory; specific laminate problems; general (F.E.) analysis programs; miscellaneous problems. The programs are not discussed in the report...
report 1990
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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
document
Houwink, R. (author), van der Vooren, J. (author)
Paper presented at AIAA 12th Fluid and Plasma Dynamics Conference held in Williamsburg, Virginia, 23-26 July 1979. Using an improved version of the NASA Ames code LTRAN2, unsteady airloads were computed for a flat plate and a lifting transonic NACA 6k A006 airfoil, for harmonic pitch and control surface motions at reduced frequencies based on...
report 1979
document
de Boer, A. (author), Riks, E. (author)
In this report a description is given of the nonlinear package of B2000. The set-up of the continuation procedure which controls the nonlinear calculations is explained. At some points the existing continuation procedure was modified to enhance its performance. The nonlinear package contains a nonlinear rod element and a nonlinear thick shell...
report 1988
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Daniels, H.A.M. (author)
In this paper the CAD system DESTIP is described. DESTIP is developed at the NLR for designing compression panels in wing box structures. Application of the system yields optimal panels in the sense that they meet all the requirements imposed by the designer and have minimum weight per unit width. Weight reductions ranging from 0 to 10% have...
report 1985
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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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