The aerodynamical laboratory of the Vienna Technical High School

We will give here only a short explanation of the operation of the plant and deal principally with the question of what it has accomplished

Aeromechanical experimentation (wind tunnel tests)

The following report endeavors to show that aeromechanical experimentation has become an important aid to theory

Deflection of Propeller Blades While Running

The forces acting on the blades of a propeller proceed from the mass of the propeller and the resistance of the surrounding medium. The magnitude, direction and point of application of the resultant to the propeller blade is of prime importance for the strength calculation. Since it was obviously impracticable to bring any kind of testing device near the revolving propeller, not so much on account of the element of danger as on account of the resulting considerable disturbance of the air flow, the deflection in both cases was photographically recorded and subsequently measured at leisure

Effect of periodic changes of angle of attack on behavior of airfoils

This report presents the results of a series of experiments, which gave some quantitative results on the effect of periodic changes in the direction of the relative air flow against airfoils. The first series of experiments concerned how the angle of attack of the wing model was changed by causing the latter to oscillate about an axis parallel to the span and at right angles to the air flow. The second series embraced all the experiments in which the direction of the air flow itself was periodically changed

Plunging Airfoil: Reynolds Number and Angle of Attack Effects

Natural flight has consistently been the wellspring of many creative minds, yet recreating the propulsive systems of natural flyers is quite hard and challenging. Regarding propulsive systems design, biomimetics offers a wide variety of solutions that can be applied at low Reynolds numbers, achieving high performance and maneuverability systems. The main goal of the current work is to computationally investigate the thrust-power intricacies while operating at different Reynolds numbers, reduced frequencies, nondimensional amplitudes, and mean angles of attack of the oscillatory motion of a NACA0012 airfoil. Simulations are performed utilizing a RANS (Reynolds Averaged Navier-Stokes) approach for a Reynolds number between 8.5×10^3 and 3.4×10^4, reduced frequencies within 1 and 5, and Strouhal numbers from 0.1 to 0.4. The influence of the mean angle-of-attack is also studied in the range of 0º to 10º. The outcomes show ideal operational conditions for the diverse Reynolds numbers, and results regarding thrust-power correlations and the influence of the mean angle-of-attack on the aerodynamic coefficients and the propulsive efficiency are widely explored.Fundação para a Ciência e a Tecnologia e Santander-UBIinfo:eu-repo/semantics/publishedVersio

Delaunay graph mapping based mesh deformation for simulation of a spanwise rigid and flexible flapping NACA0012 wing using DES with parallel implementation

A flapping NACA0012 wing with spanwise rigid and flexible configurations is simulated using the Delaunay graph mapping based mesh deformation technique. This mesh deformation scheme is quite efficient and gives a good alternate to the spring analogy due to its non-iterative nature and simple implementation. It is also well suited for the parallel implementation due to its preservation of the original mesh topology. The preliminary simulated case is spanwise rigid at Garrick frequency of 1.82 and Reynolds number 30,000, corresponding to the experimental data by Heathcote et. al [AIAA- 2006-2870]. The results obtained for this case are in a good agreement with the experimental data for the instantaneous thrust. The simulation also predicts the lag in flapping motion cycle and generated thrust due to the dynamic effects of the flapping cycle and a corresponding phase lag is depicted in the thrust during the flapping cycle. The detailed paper will also include the implementation and results of the spanwise flexible flapping NACA0012 wing

Vortical Patterns in the Wake of an Oscillating Airfoil

The vortical flow patterns in the wake of a NACA 0012 airfoil pitching at small amplitudes are studied in a low speed water channel. it is shown that a great deal of control can be exercised on the structure of the wake by the control of the frequency, amplitude and also the shape of the oscillation waveform. An important observation in this study has been the existence of an axial flow along the cores of the wake vortices. Estimates of the magnitude of the axial flow suggest a linear dependence on the oscillation frequency and amplitude

Standardization and aerodynamics

Aerodynamics being a new science and not having the traditions which burden the older sciences can easily be standardized and the methods of work adopted in the various laboratories brought into line

An Experimental and Numerical Investigation of Flapping-Wing Propulsion

AIAA Paper No. 99-0995, 37th AIAA Aerospace Sciences Meeting, Reno, Nevada, Jan. 1999.Flapping-wing propulsion is investigated experimentally and numerically with direct comparisons between experimental and numerical thrust measurements for several geometrically simple configurations. Numerical simulations are performed using linear theory, and a previously developed, unsteady panel method that models one or two independently moving airfoils with three-degrees of freedom and non-linear deforming wakes. Experiments are carried out in the Naval Postgraduate School 5'×5' low-speed tunnel. A flapping mechanism that approximates the two-dimensional motions modeled by the panel code is suspended with cables in the wind tunnel, and thrust measurements are made by measuring the streamwise displacement of the model using a laser range-finder. The experimental flapping mechanism utilizes variable aspect-ratio wings and optional tip plates to investigate the effect of three-dimensionality. The device flaps two airfoils, each with two degrees of freedom and adjustable pitch and plunge amplitudes, and additional stationary wings may be attached up and/or downstream of the flapping wings to investigate interference effects

NACA Technical Memorandums

This report presents the results of a series of experiments, which gave some quantitative results on the effect of periodic changes in the direction of the relative air flow against airfoils. The first series of experiments concerned how the angle of attack of the wing model was changed by causing the latter to oscillate about an axis parallel to the span and at right angles to the air flow. The second series embraced all the experiments in which the direction of the air flow itself was periodically changed