Modified version of LTRAN2; a calculation method for inviscid transonic flow about thin airfoils in moderately slow unsteady motion

A method is discussed for the calculation of inviscid transonic flow about thin airfoils in moderately slow unsteady motion. It is an extension of a method which was developed by Ballhaus and Goorjian of NASA Ames and which is applicable for strictly slow unsteady motions only. The modifications involve extra unsteady terms in the boundary...

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...

Aspects of second- and third-order panel methods demonstrated for the two-dimensional flat plate problem

Characteristics of three second-order and two third-order panel method formulations for the incompressible flow about a flat plate at incidence are investigated. The second order methods employ quadratic representations for the doublet distribution, either based on quadratic B-splines or on a combination of a Taylor series expansion and finite...

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...

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...

Preliminary design and analysis of procedures for the numerical generation of 3D block-structured grids

An analysis of various alternative approaches in grid generation is presented. A grid-generation procedure for complex aircraft configurations could be based on a combination of three subprocesses, . decomposition of the flow domain into about 100 hexahedronal blocks, . trilineair transfinite interpolation to generate initial grid point...

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...

Numerical simulation of leading-edge vortex flow

An analysis is presented of results of a computational method to simulate the steady compressible vortical type of flow around a 65-deg sharp-edged cropped delta wing. The discussion emphasizes some more fundamental aspects of the numerical simulation such as the separation of the flow, the structure of the leading-edge vortex core and the flow...

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...

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)...