Mathematical modelling and numerical simulation of a two-phase heat transport system condenser

The mathematical modelling and numerical simulation of a condenser is discussed. This mathematical model is part of the NLR approach to model and scale two-phase heat transport systems (for space). During a previous study the condensation length required for various gravity conditions, and working fluids has been investigated by means of...

Predesign of a simulator for inverse robot kinematics

An inverse robot kinematics method is being developed that is to be applicable to any sequential rigid robot. In this report, first requirements are identified and a survey of existing methods is given. An. evaluation of these methods with respect to the requirements then shows that a method based on optimization is the best candidate. It...

De plaats van de wiskundige bij de ontwikkeling van digitale simulatie-systemen voor toepassingen uit de "Computational physics"

NLR mainly performs applied scientific research for use in the aerospace industry. In many cases the product has the form of an information system for the design, production and usage of aerospace vehicles. Within this context, the mathematician contributes, in cooperation with specialists from other disciplines such as aerodynamics, structures,...

A perspective of mathematical simulation and optimization techniques in computer aided design

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...

Dynamics of flexible spacecraft: the internal balancing approach towards mathematical model order reduction

Mathematical models of the dynamics of spacecraft are needed to carry out numerical simulations, to gain insight into the characteristics of the spacecraft dynamics, and to synthesize control algorithms suitable for online system Identification, estimation, and control. Increases in size and mechanical complexity of spacecraft result in...

Simulation and optimization techniques in computer aided design

The use of numerical simulation and optimization techniques is rapidly expanding in all fields of engineering design. The place and the potential of these techniques in the design process, as well as their use by the designer, are discussed. The principles underlying these techniques are outlined and an overall view is given of the various...

A model and experimental analysis of pilot decision making behaviour for various approach conditions

This report deals with an investigation of pilots' failure detection performance in a realistic moving-base flight simulator. The task considered was the monitoring of stabilized automatic approaches. Abnormal conditions (excessive windshears or system failures) were to be detected on the basis of unacceptable deviations of displayed variables...

Estimation of load exceedances of an aircraft undercarriage with nonlinear properties excitated by random runway unevenness

In this report various methods to describe a landing gear with nonlinear properties and excitated by random runway unevenness during taxying have been investigated. The results of calculations have been compared to measured results from an analog computer simulation. The mean behaviour, standard deviations and power spectra, can be described...

A check of crack propagation prediction models against test results generated under transport aircraft flight simulation loading

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...

Towards digital computer simulation of the dynamics of flexible spacecraft

Software design for digital computer simulation of the dynamics of flexible spacecraft equipped with actuators and sensors, should take into account two properties of the overall system: (i) s.ampled-data control of the spacecraft leads to discontinuous inputs (forcing functions) in the differential equations of motion, thereby requiring...

Investigation on a passenger ride-comfort improvement system with limited control surface actuator performance for a flexible aircraft

For the low wing-loading aircraft, considered in this investigation, vertical acceleration appeared to be an important factor concerning passenger comfort. To reduce vertical motions, a ride-comfort improvement system was introduced. Determination of parameters of the system, like gains and allowable performance limitations, required analog...