DE102009035689A1 - Fluid-dynamic effective rotor e.g. propeller, for use in e.g. ship, has contour regions arranged in relationship e.g. coincidental relationship, of part of rotor blades so that regions blow-out waves of specific wavelength and frequency - Google Patents

Abstract

The rotor e.g. propeller (30), has rotor blades (31) arranged around a preset angle and spaced from each other about a rotational axis (34) and having a preset contour. The contour of the rotor blades has contour regions producing waves spreading in a fluid e.g. gas such as air, and liquid such as water, during rotation of the rotor about the rotational axis. The contour regions producing the waves are arranged in a relationship e.g. coincidental relationship, of a part of the rotor blades so that the contour regions blow-out waves of specific wavelength and frequency.

Description

The The invention relates to a fluid dynamic rotor, the order a rotation axis is rotatable and has a number of rotor blades, spaced from each other by a predetermined angle Rotary axis are arranged and each having a predetermined contour, being the contour of the rotor blades upon rotation of the rotor about the axis of rotation propagating in the fluid Having waves generating contour areas. Such a rotor is For example, a propeller, a propeller, a rotor of a Helicopter or the rotor of a wind turbine, or the like. The fluid in which the rotor is effective can be a gas, in particular Air, or a liquid, especially water. The rotor can but also, for example be the rotor of a pump or a turbine and the fluid any other liquid or gaseous Medium.

fluid Dynamic effective rotors, ie rotating propellers, rotor blades, propellers or Wind turbines generate wave vibrations, noise or radiate sound, which can lead to different effects perceived as disadvantageous, like noise pollution, Detection of sound, location of sound origin or classification the sound origin by signatures, depending on the field of application or Use of the rotor.

The The object of the invention is a fluid-dynamic rotor in which the generation of waves propagating in the fluid is reduced.

The The object is achieved by a rotor having the features of claim 1 solved. Alternative solutions are in the claims 2 and 3 indicated.

advantageous embodiments or refinements of the rotor according to the invention are specified in the subclaims.

By the invention provides a rotor having a fl uid-dynamic effect, which is rotatable about an axis of rotation and has a number of rotor blades, spaced from each other by a predetermined angle Rotary axis are arranged and each having a predetermined contour, being the contour of the rotor blades upon rotation of the rotor about the axis of rotation, waves propagating in the fluid having generating contour regions. According to the invention the wave-generating contour regions of at least part of the rotor blades in a relationship arranged, which extinguishes special wavelengths and thus frequencies or as another optimization goal essentially in an incommensurate relationship arranged to each other.

According to one Aspect of the invention it is provided that the wave-generating Contour areas in a ratio at least a part of the rotor blades arranged to each other are so that they wipe out waves of certain wavelength and thus frequency.

According to one second aspect of the invention, it is provided that the wave-generating Contour areas in a substantially random (random) ratio at least a part of the rotor blades are arranged to each other.

According to one third aspect of the invention, it is provided that the ellenerzeugenden Contour areas in a substantially incommensurate ratio at least a part of the rotor blades are arranged to each other.

According to one embodiment The invention provides that the waves generating Contour areas in the form of edge sections of a rotor blade are given in a relationship are arranged to each other, so that the waves with a phase difference be generated, which extinguishes certain wavelengths and thus frequencies.

According to one another embodiment The invention provides that the waves generating Contour areas in the form of edge sections of a rotor blade which are arranged in a substantially random relation to each other are.

According to one another embodiment The invention provides that the waves generating Contour areas in the form of edge sections of a rotor blade which are in a substantially incommensurate relationship to each other are arranged.

there can the individual edge sections of the rotor blade by local minima and / or maxima of the rotor contour are separated from each other or the local minima and / or maxima are themselves effective contour.

According to one embodiment are the distances the maxima in pairs unequal and in the order of avoidable Wavelengths, where their pairwise relationships no rational breaks are.

According to one further execution are the distances normal to the contour of the minima in pairs unequal and in the order of magnitude of wavelengths to be avoided, being their pairwise relationships no rational breaks are.

According to one another embodiment are the normal distances to the contour between maxima and minima in pairs unequal and in the order of magnitude of wavelengths to be avoided, being their pairwise relationships are not rational breaks.

In addition are the lateral structure distances in the order of magnitude the wavelengths of frequencies to be avoided for overlapping of the generated waves in the far field by diffraction at the wave edges.

According to one another embodiment According to the invention, the contour regions generating the waves pass through Corresponding contours of different rotor blades of the Rotor, in each case in pairs unequal angles with respect to Rotor axis are arranged to each other and their pairs angular relationships no rational breaks are.

Of the fluid dynamic rotor may be a propeller.

Of the fluid dynamic rotor can be a ship's propeller.

Of the fluid dynamic rotor can be a rotor of a helicopter be.

Of the Fluid dynamic rotor can be the rotor of a fan, compressor or the turbine of a jet engine.

Of the fluid dynamic rotor can be the rotor of a wind turbine be.

Of the Rotor can be a double rotor.

Of the fluiddynamically effective rotor, the rotor (paddle wheel) a Be a turbine.

According to one embodiment According to the invention, the rotor can be point-symmetrical with respect to the axis of rotation Configuration with two opposite each other rotor blades to have.

According to one embodiment of the invention, the wave-generating contour regions may be arranged in an approximate incommensurate relationship with q _{incommensurable} = q _{commensurable} + δq _g with q _{commensurable} = n / m (rational fraction), δq _g : misfit parameter

in the Below are embodiments of the Invention explained with reference to the drawing.

It shows:

1a a schematic representation of a model of the propagation of wave surfaces as a superposition of a number of individual elementary waves;

1b a schematic representation of a model of the propagation and diffraction when the lateral extent is in the order of the wavelength. As a result, laterally arranged wavefronts in the far field mix by broadening.

2 Models of sound-producing surfaces with commensurate and profitable structures;

3 an exemplary representation of amplitude modulation based on an embodiment of the invention;

4a ), b) and c) is a schematic representation showing the separation of wavefronts of even and modulated edges, as well as the principle of broadening and extinction of a particular wave;

5 a representation of a modern propeller of an aircraft, in particular a plane according to the prior art;

6a ) to c) an illustration of a propeller for an aircraft, in particular an aircraft, according to an embodiment of the invention with incommensurately modulated edges of the propeller blades;

7 a perspective view of a propeller of an aircraft in the form of a double propeller with incommensurately structured edges of the propeller blades according to another embodiment of the invention;

8a ) and b) a view of a helicopter or a perspective view of its main rotor according to a further embodiment of the invention, in which the rotor is designed as a double rotor with each incommensurately structured rotor blades;

9 a plan view of a propeller of the compressor, fans or the turbine of an engine for an aircraft, such as an aircraft, or a tail rotor of a helicopter according to another embodiment of the invention;

10a ) and b) a view of a propeller according to an embodiment of the invention or a partial view of one of the screws leaves thereof having incommensurately structured edges;

11a ) to c) a view of a conventional propeller ( 11a )) or of propellers according to further embodiments of the invention, 11 b) and c) in which the screw blades also have incommensurately structured edges;

12a ) to c) a wind turbine with a conventionally designed rotor, 12a ), or incommensurately configured rotors according to embodiments of the invention, 12b ) and c);

13 a view of a humpback whale showing the incommensurability using an example from nature;

14 to 17 Further illustrations of the humpback whale fin to illustrate the incommensurability using the example Buckelwalflosse.

In the 1a A model representation of the propagation of a wavefront or wavefront, as shown in FIG. 2, makes use of a model according to which a wavefield can be thought of as a superposition of elementary waves emanating from an earlier wavefront. According to this construction, known as Huygens'sche principle, the new wave front II results as a superposition of elementary waves, which emanate from an old wave front I. In three dimensions, the elementary waves are spherical, in two dimensions, as in 1 shown, circular. Each point of an old wave front I can thus be understood as the starting point of a new wave, namely the said elementary wave. Likewise, any point on a sound generating surface, such as a contour or edge of a propeller, a rotor, a propeller, or the like, generally referred to herein as a fluid dynamic rotor, may be interpreted as the origin of such elementary waves.

1b shows the construction, according to the same principle, of a plane wave with finite lateral extent. This results in diffraction at the ends. If the lateral extent of the wave is of the order of magnitude of the wavelength, the diffraction at the ends is noticeable, the wave propagates. This leads to a mixing of laterl adjacent generated waves in the far field.

Starting from a regular structure, ie in particular such a fluid-dynamic rotor having smooth contours or edges generating waves propagating in fluid, such a smooth edge or contour can be understood as the origin of an elementary wave which can be represented by a regular grid, such as Curve a in 2 shown, with the points a 2 deliver the position of the edges. Such a regular structure may further have a commensurate superstructure, which is any multiple of the wavelength of the grating, in FIG 2 three times the smallest wavelength λ _a .

Curve b in 2 now shows a modulation of the imaginary grid, in which only the commensurate superstructure with λ _{superstructure} = 3λ _g origin of the phase difference of propagating in the fluid waves. Such a commensurate superstructure therefore has a modulation with λ _m / λ _g = m / n = 3/2, q _m / q _g = n / m = 2/3.

Curve c in 2 Finally, an incommensurate structure showing no superstructure to that in curve a of FIG 2 The regular grid shown in FIG. 1, ie no zero point of the curve c of the incommensurate structure, will ever again strike a zero point of the curve of the regular structure of the curve a.

2 also shows a possible transfer of an incommensurate structure to the arrangement of edge portions.

3 shows on the basis of an embodiment of the invention, the principle of incommensurability. Starting from a regular structure A, which corresponds to curve a of 2 may be modulated by a regular grating having a wavelength λ _regular grating, a commensurate (with superstructure) or incommensurate amplitude variation b may be provided. 3c , d shows a carry a structure (here incommensurable, also differently optimized structures are possible, as for the extinction of special wavelengths or randomly (random)) on the arrangement of the edges. The orientation of the edges ( 3c , d) can follow further optimization criteria. For rotors, it is important to pay attention to an adapted arrangement of the blade tips.

In the context of the invention, it is sufficient if the contour regions generating the waves of at least part of the rotor blades, essentially the blade tips, are arranged in a substantially incommensurate relationship to one another. This is fulfilled, for example, if the contour regions i, j, k (FIG. 211 . 312 . 313 ) in an approximately incommensurate relationship with q _{incommensurable} = q _{commensurable} + δq _g with q _{commensurable} = n / m (rational fraction), δq _g : misfit parameter
are arranged. The misfit parameter δq _g is chosen so that the generation of fluid-propagating waves in the desired manner is reduced in the fluid-dynamic rotor.

4a ) respectively. 4b ) shows by means of a smooth, straight wave-generating edge or contour 10 and the in 3 shown incommensurate structure 20 the different propagation behavior of the propagating in the fluid, generated by the respective contour wave and the principle of extinction. While in the case of in 4a ) shown smooth edge a regular propagation of wavefronts I, II, III according to the in 1 shown Huygens'schen principle takes place, in the case of 4b ), an increasing resolution of wavefronts with their progression, as shown by wavefronts I ', II' and III '. While the individual wavefronts still run side by side after being detached from the incommensurate edge in the near field, cf. I 'and II', takes place in the far field, a mixture of the same, as the "softened" wavefront III 'shows, so that the original wavefront increasingly dissolves into an indefinable noise. This leads firstly to a reduction of radiated noise from, for example, propellers, rotor blades, propellers or the rotors of wind turbines, on the other hand, the resolution of the wavefronts shown to an aggravation of detection of sound, locating the sound source and classification of the sound origin by signatures, for example in military used air or water vehicles.

4c shows the principle of cancellation for a particular contour arrangement and a particular wavelength. Does this arrangement z. B. for this wavelength and at this location by superposition of the waves to extinguish, it may also be amplifying for other wavelengths. 4c shows on the one hand how one can extinguish certain wavelengths in one place. This makes sense if few wavelengths dominate in the Fourier spectrum of the generated noise. This is the case with rotors where a frequency ω = ω _red n _{number of leaves} dominates.

To the other shows 4c the principle as it is in 4a reinforcing and in 4b diffusing effect. In 4b be the many waves, analogous than their two in 4c , added with random (random) or incommensurate shifted phases.

5 shows in frontal plan view of a modern propeller of a transport aircraft according to the prior art. The propeller 10 includes a number of propeller blades 11 , which is attached to a hub 12 around a central axis 13 are rotatably arranged, as is well known in the art.

6 shows a propeller according to an embodiment of the invention, which in its basic configuration similar to that in 5 shown conventional propeller is constructed. The propeller 20 this embodiment again comprises a number of propeller blades 21 , which is attached to a hub 22 around a central axis 23 are provided rotating. Unlike the propeller blades 11 of in 5 shown conventional propellers 10 are the rotor blades 21 of the propeller according to the invention 20 however, provided with incommensurable edges or contours, as in 6a ) and b) enlarged. The incommensurate design of the rotor blades 21 is similar to the one in 3 or in 4b ) shown. The leaves 21 of the propeller according to the invention 20 can, but need not be the same in terms of the structure of their edges, provided they have the same propulsion, the same resistance and the same intrinsic angular momentum to avoid imbalance. The rotor blades 21 can be adjustable about their own axis, as in 4b ) indicated.

In 7 is an embodiment of the invention with reference to a modern double propeller 30 which has a first rotor with respective first rotor blades 31a and a second rotor having respective second rotor blades 31b has, which are provided in a conventional manner for an opposite rotation. The individual rotor blades 31a respectively. 31b are in turn provided with incommensurable structured edges or contours, in which case also the propeller blades 31a respectively. 31b each of the first and the second rotor may be equal to each other, but need not be the same, again if they have the same propulsion, the same resistance and the same intrinsic angular momentum to avoid imbalance. The propeller blades 31a of the first rotor and the propeller blades 31b of the second rotor may be different, but need not. For optimal reduction of the vibrations generated by the propellers or waves can be provided that from the first (front) propeller 31a detaching wavefronts are "soft" and the edges of the second (rear) propeller are incommensurably fractured to allow "soft" dipping of the blades of the second rotor into the wavefronts of the first one. Although the second propeller is not in the far field of the first, but in the near field, nevertheless, the construction meets the aforementioned criteria.

8a ) and b) shows another embodiment of the invention applied to the double rotor 40 . 50 a helicopter 400 , The first (upper) rotor 40 includes two rotor blades 41 , the second (lower) rotor 50 includes two rotor blades 51 , the rotors 40 . 50 together are a zen trale axis 53 arranged and controllable in a conventional manner.

As 8b ) shows are the individual rotor blades 41 . 51 each again provided with incommensurable designed edges or contours, and here too the rotor blades 41 respectively. 51 each of a rotor 40 respectively. 50 can be equal to each other, but not need, as long as they are similar in terms of propulsion, resistance and angular momentum.

in the Trap of a helicopter with a single rotor, in the drawing not shown, would be according to the invention the rotor blades the single rotor again incommensurate in the sense of the invention designed. In a single rotor this beats in the vortex, which from the then necessary tail rotor replace the helicopter. Again, it is important that the wavefronts extending from the tail rotor replace, are "soft", and the edges of the main rotor of the helicopter incommensurable are broken (anti buffeting).

9 Now shows a further embodiment of the invention with reference to a rotor or compressor of an engine or propeller 60 which is a number of rotor blades 61 which has in common about a central axis 63 rotatable on a hub 62 are arranged. The individual rotor blades 61 each have corresponding characteristic contours 611 . 612 . 613 . 614 in the case illustrated, these are the nose-side contours of the individual rotor blades 61 , These corresponding contours 611 . 612 . 613 . 614 and thus the individual rotor blades 61 themselves are in pairs unequal angles α ₁ , α ₂ , ... α _n with respect to the rotor axis 63 arranged. The pairwise angular relationships α ₁ / α ₂ , α ₁ / α ₃ ,... Α ₂ / α ₃ ... Α _n-1 / α _n are not rational fractions, so that the rotor blades 61 are in an incommensurate relationship to each other, the resulting superstructure corresponds to 360 °, so one revolution. After one complete revolution, the rotor is located 60 again in the original position, ie the superstructure corresponds to that of a complete revolution. Compared to a conventional propeller with equidistantly arranged leaves (in 9 indicated by dotted lines), in which the angular frequency of the oscillation is given by ω = ω _red × n _{number of leaves} , the angular frequency of the oscillation decreases to that of the rotor speed ω _red . The frequency of the oscillation is therefore lower by a factor which corresponds to the number of sheets n the _{number of sheets} than with a conventional propeller, which is of great advantage.

The construction of the propeller 60 must have the center of gravity as well as an inertial ellipsoid axis on the rotor axis 63 Despite incommensurable angle construction, this can be calculated by means of modern design and variation methods. A simplification results from a rotation axis 63 point-symmetrical construction, ie in each case two opposing propeller blades 61 are arranged the same and the same, but then results in a half as large superstructure with a correspondingly doubled repetition frequency of 2ω _red .

An incommensurate variation of the angles α ₁ ... α _n is better in the result than in a random distribution of the same.

The 10 and 11 show embodiments of the invention with reference to marine propellers 70 respectively. 80 each with incommensurable designed screw blades 71 respectively. 81 , For comparison, in 11a ) a conventionally designed propeller, in which the screw blades 81 have smooth edges. As the 10a ) respectively. 11b ) and c), as well as the enlarged illustration in 10b ) show, have the individual rotor blades 71 respectively. 81 again incommensurable designed edges or contours 711 . 712 respectively. 811 . 812. as previously based on the 3 and 4 explained. Again, the rotor blades 71 respectively. 81 a screw 70 respectively. 80 can not be equal to each other, but can, but they should have the same propulsion, the same resistance and the same intrinsic angular momentum to avoid imbalances. At the in 10 In the embodiment shown opposite leaves can be made the same, so that the screw is constructed point-symmetrical.

12 shows an embodiment of the invention, which is applied to the rotor 90 a wind turbine. The rotor 90 has a number, here three, of rotor blades 91 , which is attached to a hub 92 around a central axis 93 are rotatably provided. In 12a ) is a conventionally designed rotor for comparison 90 shown. 12b ) shows a rotor 90 each with identically designed rotor blades 91 , which, however, at different angles about the rotor axis 93 is arranged, wherein the angles are mutually unequal in pairs and are in a pairwise unequal irrational relationship, ie α ₁ / α ₂ , α ₁ / α ₃ , α ₂ / α ₃ are not rational fractions and pairs unequal. At the in 12c ) are the contours 911 . 912 the rotor blades 91 even incommensurable, similar to the previous one with reference to the 3 and 4 explained. The measures according to 12b ) and 12c ), ie an incommensurability of the angles of the rotor blades or an incommensurability of the design of their edges or contours, may be provided individually or together.

The 13 to 17 show by means of the From the natural example of the humpback whale fin again the different aspects of incommensurability of the edge or contour design. According to 13 The lateral structure distances d ₁ ... d _n vary in an optimized manner in the order of magnitude of the wavelengths of frequencies to be avoided in order, according to Huygens, to broaden and thus mix the laterally separated waves.

In 14 shows that the distances of the edge projections of the front and rear edges of the fin d ₁ ... d _n (preferably) are all unequal in pairs and their ratios d ₁ / d ₂ , d ₁ / d ₃ ... d ₂ / d ₃ . .. d _n-1 / d _n (preferably) are all irrational and (preferably) all in pairs are unequal. The same applies to the incommensurate distances of the edge valleys (minima) of front and rear edges or contours in the humpback whale tail according to 17 and for the incommensurable distances between edge protrusions and edge valleys or front contours and back contours of each of the leading and trailing edges of the humpback whale fin, only a few of which are shown. Again, the said distances d ₁ ... d _{n are} preferably all unequal and their ratios d ₁ / d ₂ , d ₁ / d ₃ ... d ₂ / d ₃ ... d _n-1 / d _n (preferably) are all irrational and (preferably) all in pairs are unequal. In an incommensurate structuring of edges or contours according to the invention, the wavefronts, with dispersion and broadening at the edges, extend in partial waves in different directions and with a predetermined, random or incommensurately shifted phase, the additional diffraction occurring at the edges thereof the extent of the wavefronts in the range of the essential wavelengths of the vibrations generated passes, so that in the far field only a noise is recorded.

For the purposes of the invention, it is sufficient if the contour regions generating the waves of at least one part of the rotor blades, preferably at the blade ends, are arranged in a substantially incommensurate relationship to one another. This is fulfilled, for example, when the contour areas generating the waves 211 . 212 . 213 ; 611 . 612 . 613 . 614 ; 811 . 812. ; 911 . 912 in an approximately incommensurate relationship with q _{incommensurable} = q _{commensurable} + δq _g with q _{commensurable} = n / m (rational fraction), δq _g : misfit parameter
are arranged. The misfit parameter δq _g is chosen so that the generation of fluid-propagating waves in the desired manner is reduced in the fluid-dynamic rotor.

Claims (20)

Fluid dynamically effective rotor, which is rotatable about an axis of rotation and having a number of rotor blades, which are arranged at a predetermined angle spaced from each other about the axis of rotation and each having a predetermined contour, wherein the contour of the rotor blades upon rotation of the rotor about the axis of rotation itself Having in the fluid propagating waves generating contour regions, characterized in that the waves generating contour regions ( 211 . 212 . 213 ; 611 . 612 . 613 . 614 ; 811 . 812. ; 911 . 912 ) in a ratio of at least a part of the rotor blades ( 21 ; 31 ; 41 ; 51 ; 61 ; 71 ; 81 ) are arranged to each other so that they wipe waves of certain wavelength and thus frequency. Fluid dynamically effective rotor, which is rotatable about an axis of rotation and having a number of rotor blades, which are arranged at a predetermined angle spaced from each other about the axis of rotation and each having a predetermined contour, wherein the contour of the rotor blades upon rotation of the rotor about the axis of rotation itself Having in the fluid propagating waves generating contour regions, characterized in that the waves generating contour regions ( 211 . 212 . 213 ; 611 . 612 . 613 . 614 ; 811 . 812. ; 911 . 912 ) in a substantially random (random) ratio of at least a portion of the rotor blades ( 21 ; 31 ; 41 ; 51 ; 61 ; 71 ; 81 ) are arranged to each other. Fluid dynamically effective rotor, which is rotatable about an axis of rotation and having a number of rotor blades, which are arranged at a predetermined angle spaced from each other about the axis of rotation and each having a predetermined contour, wherein the contour of the rotor blades upon rotation of the rotor about the axis of rotation itself Having in the fluid propagating waves generating contour regions, characterized in that the waves generating contour regions ( 211 . 212 . 213 ; 611 . 612 . 613 . 614 ; 811 . 812. ; 911 . 912 ) in a substantially incommensurate ratio of at least a portion of the rotor blades ( 21 ; 31 ; 41 ; 51 ; 61 ; 71 ; 81 ) are arranged to each other. Fluid dynamically effective rotor according to claim 1, 2 or 3, characterized in that the waves generating contour areas ( 211 . 212 . 213 ) in the form of edge sections ( 211 . 212 . 213 ; 811 . 812. ; 911 . 912 ) of a rotor blade ( 21 ; 31 ; 41 ; 51 ; 71 ; 81 ; 91 ) which are arranged in a substantially incommensurate relationship to one another. Fluid dynamically active rotor according to claim 4, characterized in that the individual edge sections ( 211 . 212 . 213 ; 811 . 812. ; 911 . 912 ) of the rotor blade ( 21 ) are separated from each other by local minima (m) and / or maxima (M) of the rotor blade contour. Fluid dynamically active rotor according to claim 4, characterized in that the individual edge sections ( 211 . 212 . 213 ; 811 . 812. ; 911 . 912 ) of the rotor blade itself local minima and / or local maxima ( 2 . 3 ) form. Fluid dynamically effective rotor according to claim 5 or 6, characterized in that the distances of the maxima (M) in pairs unequal and in the order of magnitude of avoidable wavelengths and their pairwise relationships no rational breaks are. Fluid dynamically effective rotor according to claim 5 or 6, characterized in that the distances of the minima (m) in pairs unequal and in the order of magnitude of avoidable wavelengths and their pairwise relationships no rational breaks are. Fluid dynamically effective rotor according to claim 5 or 6, characterized in that the distances between maxima (M) and Minima (m) in pairs unequal and of the order of avoidable wavelength and their pairwise relationships no rational breaks are. Fluid dynamically effective rotor according to one of claims 5 to 9, characterized in that the lateral distances of the local minima (m) and / or maxima (M) of the order of the wavelengths of are to be avoided frequencies. Fluid dynamically effective rotor according to one of claims 1 to 10, characterized in that the wave-generating edge regions by corresponding contours ( 611 . 612 . 613 . 614 ) of various rotor blades ( 61 ) of the rotor ( 60 ) are given and / or in each case in pairs unequal angles (α ₁ , α ₂ , ... α _n ) with respect to the rotor axis ( 63 ) are arranged and their pairwise angular relationships (α ₁ / α ₂ , α ₁ / α ₃ , ... α ₂ / α ₃ , ... α _n-1 / α _n ) are not rational fractions. Fluid dynamically effective rotor according to one of claims 1 to 11, characterized in that the rotor is a propeller ( 20 ; 60 ). Fluid dynamically effective rotor according to one of claims 1 to 11, characterized in that the rotor is a ship propeller ( 70 ; 80 ). Fluid dynamically effective rotor according to one of claims 1 to 11, characterized in that the rotor is a rotor ( 30 ; 40 . 50 ) of a helicopter. Fluid dynamically effective rotor according to one of claims 1 to 11, characterized in that the rotor of the rotor ( 90 ) is a wind turbine. Fluid dynamically effective rotor according to one of claims 1 to 15, characterized in that the rotor is a double rotor ( 30 ; 40 . 50 ). Fluid dynamically effective rotor according to claims 1 to 11, characterized in that the rotor of the rotor of a turbine is. Fluid dynamically effective rotor according to claims 1 to 11, characterized in that the rotor of the rotor of the fan, compressor or the turbine of a jet engine. Fluid dynamically effective rotor according to one of claims 1 to 18, characterized in that the rotor ( 20 ; 30 ; 40 ; 50 ; 60 ; 70 ) one to the axis of rotation ( 23 ; 33 ; 43 ; 53 ; 63 ; 73 ) point-symmetrical configuration, each with two identical opposite rotor blades has. Fluid dynamically effective rotor according to one of claims 1 to 19, characterized in that the waves generating contour areas ( 211 . 212 . 213 ; 611 . 612 . 613 . 614 ; 811 . 812. ; 911 . 912 ) in an approximately incommensurate relationship with q _{incommensurable} = q _{commensurable} + δq _g with q _{commensurable} = n / m (rational fraction), δq _g : misfit parameters are arranged.

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