Hyperbolic grid generation with BEM source terms

A method is presented for the generation of 0-type grids about transverse cross-sections of transport type aircraft. The method combines a hyperbolic grid generation scheme with source terms obtained with a boundary element method in such a way that 0-type grids around fairly complex shapes with concavities can be generated easily. The...

Revised results of the unsteady transonic pressure measurements on the LANN model

A new postprocessing procedure is applied on the data, acquired in 1981 during the unsteady transonic pressure measurements on a transport-type supercritical wing (LANN-model), oscillating in pitch. The new procedure takes the influence into account of the local boundary layer on the dynamic response of the pressure tubes. This report presents...

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...

The international vortex flow experiment: A test case for compressible Euler codes

As part of the joint International Vortex Flow Experiment, force and pressure measurements have been carried out on a 65 deg delta wing configuration in the transonic and supersonic wind tunnels of NLR. Out of these data three test cases were selected by the organizing committee of the GAMM WORKSHOP on the "Numerical Simulation of Compressible...

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,...

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 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...

Description and validation of the two-dimensional test setup for multiple airfoils in the pressurized wind tunnel HST

A description is given of the two-dimensional test setup in the pressurized wind tunnel HST of the NLR, for the testing of multiple airfoils at high Reynolds numbers. Results of the first tests with this setup are validated. For this validation a number of additional tests were performed in the HST as well as in the atmospheric wind tunnel HST 3...

A system for the numerical simulation of sub- and transonic viscous attached flows around wing-body configurations

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...

A calculation method of the viscous flow around multi-component airfoils

The viscous flow around multi-component airfoils has been calculated by solving incompressible potential flow and boxindary layer problems iteratively. The potential flow problem is solved by a revised version of the 2D NLR panel method. A model transport equation of turbulent stress is employed to calculate the turbulent boundary layer. The...

Results of an improved version of LTRAN2 for computing unsteady airloads on airfoils oscillating in transonic flow

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...

The design and aerodynamic characteristics of an 18% thick shock-free airfoil (NLR 7501)

The design and experimental verification of a thick (18 %), shock free airfoil is described. The design was performed, using the NLR hodograph theory for transonic airfoil design. The airfoil was experimentally investigated in the NLR Pilot tunnel.

Influence of free-stream Mach number on transonic shock-wave boundary-layer interaction

An experiment is described in which a nominal normal shock impinges on a turbulent flat plate boundary layer. The wall pressure distribution in the interaction region was measured for Mach numbers in front of the shock of 1.40, 1.44 and 1.46. The Reynolds number based on shock position was 18 X 10(6) and based on momentum thickness at the start...

Investigations of the transonic flow around oscillating airfoils

Exploratory wind-tunnel experiments in high-subsonic and transonic flow on a conventional airfoil with oscillating flap and a supercritical airfoil oscillating in pitch are described. In the analysis of the experimental results, emphasis is placed upon the typical aspects of transonic flow, namely the interaction between the steady and unsteady...

Wind-tunnel measurements on the interference between a jet and a wing, located outside the jet. Part I: text, tables and figures

This report describes a wind-tunnel investigation on the interference between a jet and a wing half model, located outside the jet. Pressure distributions on the wing, and lift coefficients calculated from those have been used for evaluation of a method developed at NLR for the prediction of interference effects between jets and parts of...

Experimental investigation of the aerodynamic characteristics of a wing propulsion jets

With the intent to test the qualities of the theoretical models used in two different calculation methods, pressure distributions have been measured on a simple half model wing-in-jet combination. The position of the jets relative to the wing was varied, mainly in a plane perpendicular to the span. Jet velocities of 1, 2 and 3 times the tunnel...