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...

Evaluation of measured-boundary-condition methods for 3D subsonic wall interference

Measurements on a simple aircraft model in both an appropriately sized and a relatively large, low-speed, solid-wall test section were used to analyse the accuracy and consistency of measured-boundary-condition (MBC) methods. For completeness, the classical method of images, with two different correction procedures, was also analysed. For the...

Development of an advanced panel method for complex configurations in subsonic compressible flow; Application to the computation of the potential flow through ducts.

The application of a boundary integral or "panel" method to duct flows is described. The method is capable of computing the three dimensional, steady state, subsonic, linearized (Prandtl-Glauert) potential flow about general configurations. The method is characterized by the application of a Dirichlet boundary condition and of "compressible"...

ARSPNSC: A method to calculate subsonic steady and unsteady potential flow about complex configurations

A new method ARSPSC is described for the calculation of steady and time-linearized unsteady subsonic potential flow about complex 2-D and 3-D configurations. The method belongs to the category of the so-called panel methods. Applications have been made to a 2-D oscillating flat plate, a 2-D multi-component airfoil with oscillating flap and a 3-D...

A Transonic model representation for two-dimensional wall interference assessment

2D wall interference assessment using "Calspan Pipes"

The applicability of a multi-velocity-component static pipe, proposed by CALSPAN ATC, for measuring boundary velocity vector distributions in behalf of wall interference assessment, has been explored in two-dimensional flow. Comparisons with alternative methods to derive the local flow angle from measured pipe pressures as well as analyses of...

Correction for wall-interference by means of a measured-boundary-condition method

A description is given of a method for the determination of global corrections for wall interference in both solid- and ventilated wall windtunnels, 2D as well as 3D. The method is based on the assumption that the flow velocity is known at a control surface surrounding the model and that the main part of the flow field may be considered...

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...

Application of computational procedures in aerodynamic design

Examples are discussed of the application of computational methods in aerodynamic design problems involving interference. Amongst these are: subsonic wing-body, sting support, pylon-nacelle and pylon-store interference, high-lift devices, induced drag minimization through constrained optimization in the Treftz-plane and transonic wing-fuselage...

A quasi-simultaneous calculation method for strongly interacting viscous flow around an infinite swept wing

An outline is presented of a new code, called VISIAN, for the analysis of aerodynamic flows with strong viscous-inviscid interaction. The code is based on the recently developed quasi-simultsuieous method for the calculation of strongly interacting boundary layers. The feasibility of this method has already been demonstrated liy means of a...

SAMID: An interactive System for the Analysis and Constrained Minimization of Induced Drag of aircraft configurations

An interactive computer program system has been developed which provides induced-drag analysis, optimization and configuration-design capabilities. The program system employs subsonic far-field (Trefftzplane) analysis, and novel mathematical formulations of the constrained optimization problems which are based on calculus of variations. The...

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

Comparison of hot and cold subsonic jets in an external flow with reference to jet engine simulation

An experimental investigation was carried out concerning the effect of jet heating and external flow on the mean flow properties of a subsonic jet. A 60 mm diameter jet was tested in a wind tunnel at wind speeds of 0 and 60 m/s. Jet mach numbers varied between O.44 and 0.94 and jet total temperatures were 310 and 86O K. Velocity and temperature...

Application of the NLR Panel Method to a swept-wing/body combination with part-span flaps at low speed and comparison with experimental results

With the purpose of evaluating the adequacy of the NLR Panel Method with respect to the prediction of the flow around 3-D configurations with mechanical high-lift devices, potential flow calculations have been carried out for a swept-wing/body combination with part-span flaps at low speed. Several configurations as well as several calculation...

Calculation of the displacement effect in two-dimensional subsonic attached flow around aerofoils: examples of calculations using measured displacement thicknesses

Using measured displacement thicknesses the classical displacement effect on lift and pressure distribution has been calculated for a number of aerofoils in viscous attached flow. For this purpose the displacement concept boundary condition (in its "leak flow" form) has been incorporated in a potential flow calculation method that uses a...