Application of genetic algorithms to the design of airfoil pressure distributions

NLR participates in the ECARF (European Computation Aerodynamics Research Project) "Optimum Design" project, developing an algorithm for multi-point airfoil design. Within the ECARP project a test case has been defined for two-point design with the aid of well-specified target pressure distributions. It appears that optimization of pressure...

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,...

Wave drag determination in the transonic full-potential flow code matrics

The mathematical background is described of a method that is currently being developed at NLR to calculated wave drag in transonic potential flow. The method is a generalization and extension of Garabedian's and McFadden's idea of determining wave drag by volume-integration of the artificial viscosity. The generalization of Garabedian's and...

A nonlinear multi grid method for three-dimensional transonic potential flow

Trends in CFD for aeronautical 3-D steady applications: The Dutch situation

Current and mid-term developments in computational 3-D steady aerodynamics software at NLR, focusing on the efficient aerodynamic design of the next generation of transport aircraft, are surveyed on a global level. Following a brief review of the various levels of sophistication in physical flow modelling, and their relation to the aerodynamic...

Uitbreiding van het NLR computernetwerk met een supercomputer

FAS multigrid employing ILU/SIP smoothing: A robust fast solver for 3D transonic potential flow

ILU/SIP is shown to be a very efficient and robust smoothing algorithm within the multigrid method for the solution of elliptic (subsonic) and mixed elliptic/hyperbolic (transonic) potential flow problems. The algorithm is fully implicit and fairly insensitive to large grid cell aspect ratios; in the hyperbolic regions of the flow the algorithm...

Matrics (multi-component aircraft transonic inviscid computation system): preliminary document

In the present document the pre-design will be presented of the system MATRICS (Multi-component Aircraft Transonic Inviscid Computation System). The system will be able to calculate the inviscid steady transonic flow about complex transport aircraft under cruise conditions; both jet-aircraft and propeller-aircraft can be simulated. As such the...

Grid-size reduction in flow calculations on infinite domains by higher-order far-field asymptotics in numerical boundary conditions

An error analysis is presented of the numerical calculation of the steady flow on an infinite domain around a given airfoil by a domainsplitting (= zonal) method. This method combines a fully conservative finite-difference approximation on a finite domain around the airfoil with an approximate asymptotic solution outside this finite domain. The...

Robust calculation of 3D transonic potential flow based on the non-linear FAS multi-grid method and incomplete LU decomposition

Two relaxation-algorithms and a number of restriction/prolongation-processes are compared within a non-linear FAS multi-grid research code. Paper focuses on the choice of relaxationalgorithm, which should be fast, robust (stable convergence for all local flow directions) and insensitive (good short wave damping for all possible mesh ratios). A...