Searched for: +
(1 - 20 of 27)

Pages

List view
Grid view
document
Zwaan, R.J. (author)
Various engineering-type methods to calculate the unsteady airloads on wings in transonic flow were applied in flutter calculations for a semispan flutter model of a supercritical wing. A verification was performed on the basis of comparing flutter characteristics, in which special attention was given to the prediction of transonic dips in the...
report 1984
document
Meijer, J.J. (author), Zwaan, R.J. (author)
Het onderzoek in het kader van onderwerp S4 is gericht op het verbeteren van theoretische en experimentele methoden voor flutter- en trillingsonderzoek. De werkzaamheden voor I98I hebben voornamelijk betrekking op het ontwikkelen van een methode waarmee bewegingsvergelijkingen voor het elastisch vervormende vliegtuig direct kunnen worden...
report 1981
document
Zwaan, R.J. (author)
Transonic flutter characteristics of wings are discussed, especially the transonic dip in the flutter boundary. An. explanation of the phenomenon is given with 2-D wings as examples. A survey is presented of experimental work and prediction methods dealing with transonic flutter characteristics of 3-D wings.
report 1981
document
Houwink, R. (author), Kraan, A.N. (author), Zwaan, R.J. (author)
A wind-tunnel flutter test on a supercritical wing model is described. Objectives of the test were to investigate the transonic dip and to enable comparisons with calculated flutter characteristics in which a quasi-3-D transonic theory was used. The beginning of a transonic dip was measured and a satisfactory agreement with theory could be found...
report 1981
document
Bergh, H. (author), Tijdenman, H. (author), Zwaan, R.J. (author)
In this paper , we will consider, by means of a historical review, the role of theory and experiment in the development of unsteady aerodynamics. It is not our intention to sum up all the important contributions. We will only try to sketch roughly the changing positions of theory and experiment.
report 1980
document
Ottens, H.H. (author), Zwaan, R.J. (author)
A method to calculate the aeroelastic stability of a horizontal-axis wind turbine has been presented. Its description comprises the derivation of the equations of motion which include periodic coefficients, and the application of the Floquet transition matrix method to investigate the stability. The method is exemplified by an analysis of a 25 m...
report 1978
document
Ottens, H.H. (author), Zwaan, R.J. (author)
A method is presented to calculate the aeroelastic stability of a vertical axis wind turbine. A derivation is given of the equations of motion and the calculation method has been exemplified by sin analysis of a 5m diameter wind turbine.
report 1978
document
Ottens, H.H. (author), Zwaan, R.J. (author)
The paper presents a discussion of the aeroelastic stability of wind turbines with vertical axis (VAWT) and with horizontal axis (HAWT). Results are given for an existing 5 m VAWT test-bed with and without tie-down system.
report 1978
document
Vollan, A.J. (author), Zwaan, R.J. (author)
The first part of the present report contains a study in which the stability of very simplified models of a Darrieus rotor is considered. The influence of various structural parameters concerning tower and blades is investigated. The second part deals with the stability calculations of a strip rotor, i.e. a rotor with straight blades,...
report 1977
document
Roos, R. (author), Bennekers, B. (author), Zwaan, R.J. (author)
A description is given of a panel method for the calculation of the aerodynamic loading on harmonically oscillating wing-body configurations in subsonic flow. Neglecting their thickness, the loading on the lifting surfaces is assumed to be generated by a distribution of unsteady lifting lines The loads on the body are represented by an unsteady...
report 1975
document
Roos, R. (author), Zwaan, R.J. (author)
report 1974
document
Bennekers, B. (author), Zwaan, R.J. (author), Roos, R. (author)
A method for the calculation of aerodynamic loads on wing-store configurations oscillating in subsonic flow is presented. In this method the linearized equation for subsonic compressible flow is transformed into two sets of integral equations for the steady and a superimposed unsteady flow field. The wing loads are represented by dipole...
report 1974
document
Tijdeman, H. (author), Zwaan, R.J. (author)
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...
report 1973
document
Roos, R. (author), Zwaan, R.J. (author)
The doublet-lattice method for the calculation of pressure distributions and generalized aerodynamic forces on harmonically oscillating lifting surfaces in subsonic flow is described briefly. For a wide range of configurations calculated results are compared with results of kernel function methods and with experimental data.
report 1972
document
Zwaan, R.J. (author)
Text of a lecture presented at the Colloquium on Aeroelasticity at the Technological University of Berlin, Germany, 1 - 2 July 1971.
report 1971
document
Zwaan, R.J. (author)
Local solutions for the pressure distribution at the leading and side edges of harmonically oscillating unbalanced control surfaces have been fitted into an existing lifting surface method for wings without control surfaces. Calculated results are compared with results of other methods and with experiments.
report 1971
document
Tijdeman, H. (author), Zwaan, R.J. (author)
A kernel function method for calculating pressure distributions over wings with harmonically oscillating control surfaces in subsonic flow is briefly discussed. Comparisons of calculated and measured pressure distributions are given for different planforns, Mach numbers and reduced frequencies. An analysis is presented of pressure distributions...
report 1970
document
Zwaan, R.J. (author)
Using asymptotic matching techniques methods are developed to calculate pressure distributions on two-dimensional wings oscillating at low frequencies in high subsonic and low supersonic flow. Special attention is given to a wing with oscillating control surface. Results for such a configuration are compared with experiments.
report 1970
document
Bergh, H. (author), Tijdeman, H. (author), Zwaan, R.J. (author)
An analysis is given of pressure distributions measured on a swept wing model with harmonically oscillating control surface at subsonic to supersonic Mach numbers and at various frequencies. The influence of Mach number and finite span effects is discussed. Some comparisons are made with pressure distributions on a two-dimensional wing and with...
report 1970
document
Bergh, H. (author), Zwaan, R.J. (author)
A survey is given of existing theoretical and experimental routine methods for determining pressure distributions or generalised forces on oscillating lifting surfaces. Some comparisons between results of theory and experiment are shown. Techniques are indicated to apply measured data in development work. Tunnelwall influence on measurements is...
report 1969
Searched for: +
(1 - 20 of 27)

Pages

List view
Grid view