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...

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...

The use of panel methods with a view to problems in aircraft dynamics

A survey is given of the basic principles of the panel methods. The most frequently used methods, steady as well as unsteady, are described in some detail. Recent developments aiming at improvönent and extension of the range of applicability are reviewed. The use of panel methods for the determination of stability derivatives is discussed....

The calculation of aerodynamic characteristics of wing-body combinations at subsonic flight speeds

Surface panel methods and finite difference methods are reviewed with respect to the use in the design of aeroplanes. It is concluded that there is a need for inverse surface panel type methods to diminish the trial and error character of the design process. Finite difference methods based on transonic small perturbation theory have to be based...

Reynolds number effects on pressure and normal force distributions along conically pointed circular cylinder at free-stream mach number of 2.3

Pressure measurements have been carried out on 5 stations along a 7.5- caliber conically pointed circular cylinder at a Mach number of 2.3 and Reynolds numbers of 1.2; 4.8 and 11.1 x 106. Pressure distributions have been integrated to produce local normal force coefficients. Some pitot pressure surveys have been performed in the external flow...

An ALGOL-program for the calculation of incompressible three-dimensional turbulent boundary layers

A computer program has been prepared for the calculation of turbulent boundary layer development, based on a 3-D version of the turbulent energy method. The method is briefly discussed. The computer program is described in detail. The present program is restricted to developable surfaces.

The effect of a pylon-mounted nacelle on the flutter behaviour of a wing-pylon-nacelle configuration

Noise environment in the NLR transonic windtunnel HST

Measurements of flow disturbances in the NLR - HST on the centerline and at the sidewall showed a maximiun noise level of 1 % in Cprms at a Mach number of 0.8. This is low compared with other ventilated wall tunnels of about the same size. Space-time correlations showed that a large part of the flow disturbances concisted of upstream travelling...

Results of pressure measurements on an airfoil with oscillating flap in two-dimensional high subsonic and transonic flow (zero incidence and zero mean flap position)

On the prediction of aerodynamic loads on oscillating wings in transonic flows

Possibilities to develop calculation methods for oscillating wings in transonic flow are discussed. Special attention is given to the question of linearisation. Recent NLR results of pressure measurements on an aerofoil with flap in transonic flow are analysed. Correlations are made between steady, quasi-steady and unsteady results. Shock motion...

Calculation of unsteady subsonic aerodynamic characteristics by means of the doublet lattice method

A method is desoribed for calculating the aerodynamic loading on nonplanar, infinitely thin, harmonically oscillating airfoils in subsonic flow as originally developed by Albano, Redden, Qiesing and Kalman. The generalized aerodynamic force coefficients are determined from the calculated pressure distributions. Because of the flexibility of the...

The influence of the main flow on the transfer function of tube-transducer systems used for unsteady pressure measurements

An experimental investigation has been performed, which revealed a considerable difference between the dynamic response characteristics of a tube-trauisducer system with the entrance in still air and one having an airflow across the entrance orifice, The differences observed could be explained theoretically by modifyink the existing calculation...

Supersonic wind tunnel tests of eleven small aspect-ratio wings

The lift, drag and pitching moment characteristics of eleven small aspect-ratio half-wing models mounted on a reflection plate were determined in the range of Mach numbers fom 1.4 to 2.5 in the N.A.E. 10-inch supersonlc tunnel. Eight of the models were of the cropped delta type while the remainlng three had a cropped arrow plan form. Primarily,...