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...

Measurements in a 2-D wake and in a 2-D wake merging into boundary layer: Data report

Extensive measurements of mean and fluctuating quantities in a 2-D wake shed from a flat plate and in the flow field of a 2-D wake merging into a boundary layer are described. The 'results are given in tabular and graphical form.

Application of genetic algorithms to the design of airfoil pressure distributions

NLR participates in the ECARF (European Computation Aerodynamics Research Project) "Optimum Design" project, developing an algorithm for multi-point airfoil design. Within the ECARP project a test case has been defined for two-point design with the aid of well-specified target pressure distributions. It appears that optimization of pressure...

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 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...

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...

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...

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...