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...

Computational aerodynamics of ordered vortex flows

The physical aspects, the mathematical modeling, the development and application of computational methods for the simulation of vertical flows are described. The high-Reynolds number vortex flows considered are assumed to be steady, sub-critical and such that the structure of the flow is well-ordered and consists of thin shear layers and slender...

CAR 88: A method to calculate subsonic and supersonic, steady and unsteady, potential flow about complex configurations

A description is given of the method CAR88 for the calculation of steady and time-linearized unsteady subsonic and supersonic flow about complex 2-D and 3-D configurations. The method belongs to the category of the socalled panel methods. Results of applications in supersonic flow are shown which have been made to a 2-D oscillating flat plate, a...

ARSPNS: a method to calculate steady and unsteady potential flow about fixed and rotating lifting and nonlifting bodies

A new method ARNSPNS is described for the calculation of steady and time-linearized unsteady incompressible potential flow about arbitrary lifting and nonlifting bodies in an arbitrary mean steady flow field, including rotation. The method belongs to the category of the so-called panel methods. Applications have been made to wind turbines...

A survey of computational methods for subsonic and transonic aerodynamic design

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,...

A theoretical exploration of the capabilities of 2D flexible wall test sections for 3D testing

The applicability of two-dimensional flexible solid wall test sections for three-dimensional testing is theoretically investigated for linearized subsonic flow. The method uses known interference velocity distributions along a targer line (derived from a method of images for this particular study). From these, wall shapes are calculated that...

Boundary-layer calculations on the leeward surface of a slender delta wing at incidence

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...

A survey of numerical methods for the calculation of inviscid, possibly rotational Euler flows around aeronautical configurations

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...

A system for computer aided analysis and design of multi-element airfoils

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...

Application of a constrained inverse method in the aerodynamic design of a low speed wing-slat configuration

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...

Finite difference calculation of incompressible flow through a straight channel of varying rectangular cross section, with application to low speed wind tunnels

A fully-conservative- finite difference algorithm is described to calculate the incompressible flow through a straight channel of varying rectangular cross section. Both the width and the height of the channel may vary independently. The algorithm has been used successfully in the design of the German-Dutch low speed wind tionel (DNW).

Airfoil design by the method of singularities via parametric optimization of a geometrically constrained least squares object function

The present report describes a method for the design of airfoils in incompressible flow which, subject to geometrical constraints generate approximately a given distribution of the pressure coefficient along the projection of the airfoil chord on an axis parallel to the onset flow. The flow is simulated by means of a distribution of...

Computations with the Garabedian and Korn program for two-dimensional transonic flows with embedded shocks

The report describes experiences with the Garabedian and Korn program for the computation of compressible potential flows, with or without shocks, both supercritical shockless flows and flows with shock waves. Computations for a number of quasi-elliptical aerofoils indicated that the conformal mapping procedure should be handled with care....

Evaluation of a potential theoretical model of the wake behind a wing via comparison of measurements and calculations

The present report considers the validity of the representation of the wake by discrete trailing vortices as is common practice in potential theoretical calcualtions. Theoretical results, obtained with a method developed at NLR, are compared with experimental results obtained at NLR for a 30° swept back wing. The shape of the vortex sheet as...

Application of the Woodward panel method to wings, bodies and wing-body combinations in stationary supersonic flow

Some experiences with a computer program based on a version of the Woodward panel method for the calculation of aerodynamic characteristics of bodies, wings and wing-body combinations in stationary supersonic flow are described. The method is based on the linearized theory for stationary supersonic potential flow, in which the flow around the...