A multigrid algorithm for steady transonic potential flows around aerofoils using Newton iteration

The application of multigrid relaxation to transonic potential-flow calculation was investigated. Fully conservative potential flows around aerofoils were taken as test problems. The solution algorithm was based on Newton iteration. In each Newton iteration step, multigrid relaxation was used to calculate correction potentials. It was found that...

High subsonic and transonic effects in unsteady aerodynamics

Based on experimental observations an illustration is given of typical effects occiirring in high subsonic and transonic flow around oscillating airfoils and wings. It is shown that in this speed regime the unsteady airloads are influenced considerably by the interaction of the steady and unsteady flow fields. Moreover the periodical motion of...

A Summary of Transonic Natural Laminar Flow Airfoil Development at NAE

This report contains an analysis of the experimental results obtained from four supercritical natural laminar flow (NLF) airfoils investigated in the NAE High Reynolds Number Test Facility. The airfoils have maximum thickness to chord ratios of 0.10, 0.13, 0.16 and 0.21 and were designed for a lift coefficient of CL = 0.6. Their design Mach...

VISIAN: a viscous-inviscid strong-interaction analysis system

A description is given of VISIAN - a simulation method for 2-D viscous flows with strong viscous-inviscid interaction. The mathematical mode and the numerical algorithm are presented. VISIAN has been coupled with the inviscid-flow solver TRAPS. Results are shown for a number of airfoils; a comparison is made with results from other computations...

Critical evaluation of a finite element method for the calculation of transonic flow based on constrained minimization

The method of Glowinski, Periaux and Pironneau for the calculation of transonic flow, which is based on the constrained minimization of a cost function, is critically evaluated for a case in which the transonic small perturbation equation is used. The resulting minimization problem is discretized in finite element form and solved using a...

Half-model testing in the NLR High-Speed Wind tunnel HST, a 1981 status report

A finite difference method for the calculation of transonic flow about a wing, based on a small perturbation theory

A calculation method, based upon transonic small perturbation theory, is presented for the transonic flow about a semi-wing. The influence of a body can be simulated by prescribing appropriate transverse velocities in a vertical plane through the wing root. Due to the small perturbation assumption the wing should be thin and have little dihedral...

Collection of supercritical aerofoils obtained with the NLR hodograph method

This report contains data of eighteen aerofoils, calculated with the NLR transonic hodograph theory. They give an impression about the possibilities of the calculation method for application in aerofoil design studies. The data are presented in graphical form. For two aerofoils also tabulated results are given.

A Transonic model representation for two-dimensional wall interference assessment

Demonstration of an automated CFD system for three-dimensional flow simulations

In this paper the capabilities of an automated CFD system which is currently available at NLR are demonstrated. Transonic flow around the AS28G wing/body configuration and hypersonic flow through a generic three-dimensional mixed-compression airbreathing inlet are simulated. An assessment of the level of automation of the current CFD-system is...

Clebsch variable model for unsteady inviscid transonic flow with strong shock waves

In comparison with Euler methods unsteady inviscid transonic full potential methods are known to suffer from limitations with respect to the modeling of shock waves. In this paper unsteady 2D and 3D full potential methods are extended with the Clebsch variable model. This model represents exactly the shockgenerated entropy and vorticity. The...

Adaption of structured grids based on Weighted Least Squares formulations

Computational grids are used for the discretisation of partial differential equations (PDE's) such that solution of the resulting system of algebraic equations for the discrete values of the dependent variables provides an approximation to the solution of the system of PDE's. When the discretisation of the partial differential equations (PDE's)...

Results of a new version of the LTRAN2-NLR code (LTRANV) for unsteady viscous transonic flow computations

An outline is given of a first version of the computer programme LTRAFV for coupled unsteady transonic flow/turbxilent boundary layer computations. It is a combination of the LTRAN2-NLR programme and the lagentrainment method of Green. A comparison is made of theoretical and experimental results for the NACA64A006 airfoil with oscillating flap...