Rotor blade for a wind turbine and wind turbine

Description

[0001] The present invention relates to a rotor blade for a wind turbine. Furthermore, the present invention relates to a wind turbine and a method for optimizing a wind turbine.

[0002] Rotor blades for wind turbine rotors are well known. Such rotor blades feature a profile (cross-sectional profile) that meets specific aerodynamic requirements.

[0003] In order to influence the aerodynamic properties of rotor blades, it is known to provide vortex generators on the cross-sectional profile of the rotor blades. These vortex generators comprise several swirling elements running perpendicular to the surface. These vortex generators serve to create local regions of turbulent air flow above the surface of the rotor blade in order to increase resistance to flow separation. To do this, vortex generators swirl the near-wall flow on the rotor blade, as a result of which the momentum exchange between near-wall and far-wall flow layers increases significantly and the flow velocities in the near-wall boundary layer increase. Due to the increased near-wall velocities, the flow is able to overcome pressure increases over a longer distance on the rotor blade surface.

[0004] A rotor blade and a wind turbine of the type mentioned above are known from EP 3 309 388 A1. EP 3 309 388 A1 describes a rotor blade with a suction side and a pressure side for a wind turbine, which rotor blade has a rotor blade root of a hub region for connecting the rotor blade to a rotor hub, and a rotor blade tip arranged on the side of a tip region facing away from the rotor blade root. The rotor blade has a cross-sectional profile on which several identical vortex generators are arranged next to one another in sections in the longitudinal direction of the rotor blade. The vortex generators comprise swirl elements arranged next to one another in pairs and having a length and a height. The swirl elements are each oriented at an angle to a main flow direction of the rotor blade, wherein the swirl elements arranged at the same angle have a constant lateral distance from one another.

[0005] Rotor blades for wind turbines with vortex generators or swirling elements are also known from US 2014 / 0328692 A1, US 2014 / 0328693 A1, US 9,869,297 B2 and WO 2010 / 033018 A2.

[0006] On blade sections with vortex generators, the rotor blade typically has significantly higher limiting angles of attack at which flow separation first occurs at the trailing edge than on blade sections without vortex generators. The way in which the vortex generators work inevitably causes greater frictional resistance on the profile surface of the rotor blade, i.e. the drag coefficient of the cross-sectional profile increases significantly and with it the glide ratio, the ratio of lift coefficient to drag coefficient, may even decrease. The increase or decrease in the drag ratio has a detrimental effect on the turbine yield. The influence of the glide ratio or the drag coefficient on power increases continuously from the rotor blade root to the rotor blade tip.The further away from the rotor blade root toward the rotor tip, the more important low drag coefficients and high glide ratios are for the turbine's performance and yield. Furthermore, vortex generators can contribute to increased noise emissions.

[0007] The invention is based on the object of eliminating or at least reducing the above-mentioned problem, in particular of providing a rotor blade which is characterized in the hub area by absorbing high fluctuations in the angle of attack and in the tip area by high glide ratios.

[0008] With regard to the rotor blade, the object is achieved by a rotor blade according to claim 1. The invention also leads to a wind turbine according to claim 8 and a method for optimizing a wind turbine according to claim 9.

[0009] According to claim 1, a rotor blade with a suction side and a pressure side is provided for a wind turbine, wherein the rotor blade has a rotor blade root of a hub region for connecting the rotor blade to a rotor hub, a rotor blade tip arranged on a side of a tip region facing away from the rotor blade root, and at least one vortex generator arranged between the rotor blade root and the rotor blade tip. The at least one vortex generator comprises swirl elements arranged next to one another in the longitudinal direction of the rotor blade, each having a length and a height, which are each oriented at an angle to a main flow direction of the rotor blade. The swirl elements are laterally spaced from one another in the longitudinal direction of the rotor blade. The geometry of the swirl elements varies depending on the respective distance of the arrangement of the swirl elements from the rotor blade root.

[0010] The invention is based on the idea that a wind turbine cannot be operated at a stationary operating point, but is subject to various influences that lead to a continuous change in the aerodynamic operating point. Angles of attack that exist across the cross-sectional profile of the rotor blade vary continuously during operation of the wind turbine. Parameters such as inflow turbulence, horizontal and vertical shear of the ground boundary layer, and air density in particular influence the angle of attack distribution. The effects of changes in these parameters are uneven across the rotor blade. Small-scale inflow turbulence and changes in air density, for example, result in a reduction in the tip speed ratio, which in turn causes the angle of attack to vary more in the hub area than in the tip area.

[0011] In order to increase the effort and complexity of the flow control measure when using passive flow measures, such as the arrangement of vortex generators, compared to the state of the art, a variation in the geometry of the vortex elements is provided depending on the respective distance of the arrangement of the vortex elements from the rotor blade root. Adapting the geometry of the vortex elements depending on their distance from the rotor blade root enables advantageous adaptation to the boundary conditions prevailing on the rotor blade in the rotor sections between the hub area and the tip area. By changing the geometry of the vortex elements depending on the distance, different lift coefficients and glide ratios can be achieved.These profile coefficient properties, achieved in particular by modifying the dimensions of the vortex generator's turbulence elements, precisely meet the requirements of the rotor blade.

[0012] According to the invention, the swirl elements are arranged in pairs, each oriented at a substantially opposite angle to the main flow direction of the rotor blade, with the lateral spacing between adjacent swirl elements being determined at a substantially equal angle. The paired arrangement of swirl elements ensures particularly effective vortex generation, in particular by generating counter-rotating vortices next to one another.

[0013] Preferably, the variation in the geometry of the swirl elements can result from a ratio of lateral distance to the length of the swirl element, whereby the ratio can be determined as a function of the distance. By increasing the ratio with increasing distance from the rotor root, in this case by reducing the length or increasing the spacing between identically oriented swirl elements, the maximum achievable angles of attack decrease, resulting in improved glide ratios. With a small ratio of lateral distance to the length of the swirl element, high maximum angles of attack are permissible in the hub area.

[0014] Furthermore, the variation in the geometry of the swirl elements can result from a ratio of lateral distance to height, which can also be determined as a function of distance. Accordingly, by changing the ratio depending on the distance from the rotor root—here, by changing the height of the swirl elements or by varying the spacing between identically oriented swirl elements—the maximum achievable angles of attack can be adjusted to improve glide ratios.

[0015] The relatively small ratio of lateral distance to length in the hub area makes it possible to accommodate the high angle of attack variations encountered there during operation of the wind turbine with reduced flow separation. The unfavorable glide ratios play a minor role in the turbine's yield there. Further out, a reduction in the maximum permissible angle of attack is acceptable, as occurs with an increase in the ratio of lateral distance to length or height, since the operational angle of attack variations also decrease there. This is then offset by the successively increasing influence of high glide ratios on yield.

[0016] According to the invention, the variation of the geometry of the swirl elements results from a ratio of lateral distance to the angle to the main flow direction of the rotor blade, which increases as a function of the distance with increasing distance.

[0017] The different forms of variation of the geometry can be provided individually, independently or in combination with each other.

[0018] In particular, the ratio of lateral distance to length and / or lateral distance to height of the turbulence elements may increase with increasing distance.

[0019] Preferably, the swirling elements may have a substantially triangular or fin-shaped profile.

[0020] Preferably, the length and / or the height and / or the installation angle of the swirling elements can be substantially constant. The geometric variation can then preferably be achieved by varying the lateral distances between adjacent swirling elements. This makes it possible to use only a single type of swirling element and still achieve the advantages according to the invention. Furthermore, a reduction in errors and incorrect assembly on the construction site due to mixing up the swirling elements is achieved, as well as advantages in production, since only one tool needs to be provided for manufacturing the swirling elements, for example by injection molding. As mentioned, the swirling elements are particularly preferably provided in pairs with a common base, for example as a single injection-molded part.

[0021] Particularly preferably, the swirl elements, especially in pairs, are identical, i.e., they have identical length, height, and installation angle across the entire length of the rotor blade. Several types of swirl elements are also conceivable, with the spacing between the swirl elements increasing with increasing distance from the rotor blade root.

[0022] Preferably, the variation in the geometry of the swirl elements can result from a ratio of lateral distance to an interior angle of a tip of the swirl element remote from a surface of the rotor blade, which can be determined as a function of the distance. The interior angle at the tip allows a statement to be made about how high, i.e., how large the extension perpendicular to the surface of the rotor blade is, the swirl element is in relation to its length, i.e., the extension in the plane of the surface of the rotor blade, particularly in the case of a substantially triangular or fin-shaped profile.

[0023] Furthermore, the at least one vortex generator comprises at least one base plate on which the vortex elements are arranged in pairs. Thus, vortex generators can be manufactured for different rotor sections, the vortex elements of which have a ratio of lateral distance to length and / or lateral distance to height adapted to the individual rotor sections.

[0024] A vortex generator for a rotor blade of a wind turbine is not claimed, wherein the vortex generator has a base plate with a leading edge and a trailing edge, wherein the leading edge, in the intended orientation on the rotor blade, points in the direction of the leading edge and wherein the trailing edge, in the intended orientation on the rotor blade, points in the direction of the trailing edge, thereby determining an orientation of the base plate from the rotor blade root to the rotor blade tip, wherein a plurality of vortex elements are arranged on the base plate. The geometry of the vortex elements on the base plate varies depending on the respective distance of the arrangement of the vortex elements from the rotor blade root.

[0025] The swirling elements are preferably arranged in pairs, with several pairs being particularly preferably arranged on a base plate.

[0026] The direction of the base plate, or rather the leading edge and the trailing edge thereof, is not necessarily completely parallel to a longitudinal direction of the rotor blade. For example, the base plate can also be formed parallel to the trailing edge of the rotor blade or inclined by a certain angle, for example up to 20°, preferably less than 10°, to the longitudinal direction and / or the trailing edge.

[0027] According to the invention, a wind turbine is also proposed that is equipped with one or more rotor blades according to at least one of the embodiments described above. In particular, a wind turbine with three rotor blades is proposed, each of which is designed according to one of the above embodiments.

[0028] Finally, the invention also proposes a method for optimizing a wind turbine according to claim 9, wherein the wind turbine has a rotor blade with a suction side and a pressure side for a wind turbine, and wherein the rotor blade has: a rotor blade root of a hub region for connecting the rotor blade to a rotor hub, a rotor blade tip arranged on a side of a tip region facing away from the rotor blade root, and at least one vortex generator arranged between the rotor blade root and the rotor blade tip. The at least one vortex generator comprises swirl elements arranged next to one another in the longitudinal direction of the rotor blade, each having a length and a height, which are each oriented at an angle to a main flow direction of the rotor blade, wherein the swirl elements are laterally spaced from one another.Depending on the respective distance of the arrangement of the swirl elements to the rotor blade root, the geometry of the swirl elements varies.

[0029] Further examples and advantages are described below with reference to the attached figures. These show: Fig. 1: a schematic representation of a wind turbine; Fig. 2: a schematic representation of a rotor blade; Fig. 3: a schematic representation of a vortex generator; Fig. 4: two schematic curves of a lift coefficient versus an angle of attack for an airfoil with vortex generators; Fig. 5: two schematic curves of a glide ratio versus the angle of attack for an airfoil with vortex generators; and Fig. 6: a schematic representation of a rotor blade.

[0030] Fig. 1 shows a wind turbine 100 with a tower 102 erected on a foundation 103. At the upper end, opposite the foundation 103, is a nacelle 104 (machine house) with a rotor 105, which has a rotor hub 106 and attached rotor blades 1, which are described in more detail with reference to the subsequent figures. The rotor 105 is coupled to an electric generator inside the nacelle 104 for converting mechanical work into electrical energy. The nacelle 104 is rotatably mounted on the tower 102, whose foundation 103 provides the necessary stability.

[0031] Fig. 2 shows a schematic representation of a rotor blade 1 of one embodiment. The rotor blade 1 has the rotor blade root 2 at one end and a rotor blade tip 3 at the end facing away from it. At the rotor blade root 2 or generally in the area near the rotor blade root 2, the rotor blade 1 has a large profile depth. At the rotor tip 3, on the other hand, the profile depth is much smaller. Starting from the rotor blade root 2, which can also be referred to as the profile root 2, in this example after an increase in the inner region of the blade, the profile depth decreases significantly down to a central region 4. A separation point can be provided in the central region 4 (not shown here). From the central region 4 to the rotor blade tip 3, the profile depth is almost constant, or the decrease in the profile depth is significantly reduced.The rotor blade 1 has a substantially convex suction side 7, a substantially concave pressure side, a leading edge 5, and a trailing edge 6. The pressure side and / or the suction side can also be straight or have a different shape. Reference numeral 8 denotes the overall length of the rotor blade 1.

[0032] Furthermore, the illustration in Fig. 2 Vortex generators 9, also referred to as vortex generators, are arranged on the suction side 7 of the rotor blade 1. The vortex generators 9 comprise swirl elements 10, 11 arranged side by side in pairs. The respective swirl elements 10, 11 extend in sections between the leading edge 5 and the trailing edge 6 and are each oriented at an angle to the main flow direction SR of the rotor blade 1 around which air flows, so that the pairs of swirl elements 10, 11 have a course that widens from the leading edge 5 to the trailing edge 6.

[0033] In this example, the swirl elements 10, 11 extend perpendicular to the surface of the rotor blade 1, although angles other than right angles between the swirl elements 10, 11 and the surface of the rotor blade 1 are also possible. While the vortex generators 9 are shown arranged on the suction side 7 in the example, vortex generators 9 are also possible on the pressure side as an alternative or additional option.

[0034] The swirl elements 10, 11 are arranged at a distance R from the rotor hub or the rotor blade root 2. A hub region I of the rotor blade 1 extends from the rotor blade root 2 essentially to the central region 4. A tip region II of the rotor blade 1 extends essentially from the central region 4 to the rotor blade tip 3.

[0035] Fig. 3 shows a schematic representation of an embodiment of a vortex generator 9 in perspective view. The vortex generator 9 can have at least one base plate 13, which serves to attach the vortex generator 9 to the surface of the rotor blade 1. The base plate 13 has a leading edge 14 and a trailing edge 15. Between the leading edge 14, which faces the leading edge 5 when mounted on the rotor blade 1, and the trailing edge 15, which faces the trailing edge 6, extend the respective swirl elements 10, 11, which, in this example, have a substantially triangular or fin-shaped contour.

[0036] The swirl elements 10, 11 each have a height H, wherein the height profile increases in the direction of the rear edge 15 of the base plate 13 up to a maximum value, as well as a length L, which designates the extension of the respective swirl element 10, 11 between the leading edge 14 and the trailing edge 15 or in the rotor blade plane.

[0037] The swirl elements 10, 11, each arranged side by side in pairs, are inclined at an angle to the main flow direction SR, with the adjacent swirl elements 10, 11 expanding from the front edge 14 to the rear edge 15. Two swirl elements 10, 11 arranged side by side have a substantially symmetrical orientation with respect to the main flow direction SR, i.e., one swirl element 10 of the paired swirl elements 10, 11 points outwards in the longitudinal direction of the rotor blade, and another swirl element 11 points inwards in the longitudinal direction of the rotor blade. A lateral distance between two tips of two swirl elements 10 and 11 aligned essentially in the same direction is designated by a reference number D and D 1 , respectively.

[0038] Vortex generators are a passive means of flow control. Their swirl elements, generally arranged at equal lateral intervals, cause swirling in the boundary layer flow. The swirl elements are inclined at an angle to the main flow direction. The vortex generators swirl the near-wall flow at the rotor blade, resulting in a significant increase in momentum exchange between near-wall and far-wall flow layers and an increase in flow velocities in the near-wall boundary layer. Due to the increased near-wall flow velocities, the flow is able to overcome pressure increases over a longer distance on the surface of the rotor blade. This increases resistance to flow separation.

[0039] A wind turbine does not operate at a stationary operating point, but is constantly subject to different influences, which cause the aerodynamic operating point on rotor blade 1 to change continuously. Angles of attack α, which are present across the blade radius on rotor blade 1, vary continuously during operation of the turbine. In particular, parameters such as inflow turbulence, horizontal and vertical shear of the ground boundary layer and air density, to name only the most important parameters, influence the angle of attack distribution on rotor blade 1. Small-scale inflow turbulence or changes in air density result in a reduction in the high-speed speed, which means that the angle of attack α varies more in the inner region, i.e. from the hub region I to the center region 4, of rotor blade 1 than in the outer region, i.e. from the center region 4 to the tip region II of rotor blade 1.Therefore, greater reserves for the angle of attack α during operation are provided in the inner region of the rotor blade 1 than in the outer region of the rotor blade 1. Accordingly, the vortex generators 9 are used particularly in the inner region of the rotor blade 1. By increasing the resistance to flow separation, the vortex generators 9 extend the usable range of the profile of the rotor blade 1, the so-called linear branch, in which a proportional relationship exists between lift and angle of attack.

[0040] Furthermore, the influence of the drag ratio ε or drag coefficient cw on the power increases steadily from the rotor blade root 2 to the rotor tip 3 of the rotor blade 1. As the distance from the rotor blade root 2 increases, achieving low drag coefficients cw or high drag ratios ε is essential for the performance and yield of the turbine.

[0041] For the safe operation of a wind turbine, high fluctuations in the angle of attack must be absorbed in the interior of the rotor blade 1, which can be ensured by rotor blades 1 with the vortex generators 9 arranged on them. The disadvantage of reduced glide ratios ε when using vortex generators 9 is acceptable in the interior of the rotor blade 1, since the influence of the glide ratio ε on the turbine yield in the interior of the rotor blade 1 is negligible. The further out one is on the rotor blade 1, the smaller the angle of attack ranges that must be covered and the greater the influence of the glide ratio ε on the yield of the wind turbine. To take these circumstances into account, the dimensioning of the swirl elements 10, 11 depends on the respective distance R of the arrangement of the swirl elements 10, 11 from the rotor blade root 2. This means that with increasing distance R to the rotor hub orof the rotor blade root 2, the geometric dimensions height H, length L and / or lateral distance D of the turbulence elements 10, 11 are changed.

[0042] In this case, a ratio V of lateral distance D to height H or of lateral distance D to length L is varied, whereby the ratio V of lateral distance D to height H or of lateral distance D to length L increases with increasing distance R. In the rotor hub area I, a small ratio V of lateral distance D to height H or of lateral distance D to length L is selected so that the high angle of attack variations present there during operation of the wind turbine can be covered without flow separation. On the other hand, with increasing distance R, a reduction in the maximum permissible angle of attack is acceptable, as occurs with an increase in the ratio V of lateral distance D to height H or of lateral distance D to length L. Since the operational angle of attack variations also decrease with increasing distance R from the rotor hub, this can then be taken into account by the successively increasing influence of high glide ratios on the yield.

[0043] In an alternative embodiment, an angle γ at which the swirl elements 10, 11 are located with respect to the main flow direction SR is also or alternatively varied with increasing distance R from the rotor hub or the rotor blade root 2. In particular, a lower angle with respect to the main flow direction SR is provided with increasing distance R.

[0044] In the Fig. 4 und 5 two curves 16, 17 and 18, 19 of lift coefficient c A and glide ratio ε over the angle of attack α are shown for a rotor blade 1 provided with vortex generators 9 for two different ratios V of lateral distance D to height H. The curves 16 and 18 were determined for a first ratio V of lateral distance D to height H, while the curves 17 and 19 were determined for a second ratio V of lateral distance D 1 to height H, where the lateral distance D 1 is greater than the lateral distance D.

[0045] From the Fig. 4 The curves 16 and 17 show that the maximum lift coefficient c A decreases with increasing ratio V of lateral distance D to height H. In contrast, the curves in Fig. 5 The compared curves 18 and 19 show that the maximum achievable glide ratio ε increases over a wide angle of attack range. If the ratio V of lateral distance D to height H or H or lateral distance D to length L of the swirl elements 10, 11 in the hub area I of the rotor blade 1 is chosen to be small, high maximum angles of attack α are permissible in this profile section of the rotor blade 1, although this is accompanied by a reduced glide ratio ε. If the ratio of lateral distance D to height H or H or lateral distance D to length L is increased towards the blade tip 3, the maximum achievable angles of attack α decrease in favor of improved glide ratios ε.

[0046] Fig. 6 schematically shows a rotor blade 1 in which the distance between pairs of swirl elements 10, 11 increases with increasing distance from the rotor blade root 2. Over the entire distance in the longitudinal direction of the rotor blade, the swirl elements 10, 11 are essentially identical, ie, mounted at the same angle and have identical heights H and lengths L.

[0047] By using only one type of swirl elements 10, 11, especially provided in pairs, assembly can be simplified, for example, on a construction site, since the risk of confusion and incorrect assembly of the swirl elements 10, 11 is reduced. This also offers production-related advantages, since only one production tool is required, for example, in injection-molding production.

[0048] In addition, the execution of the Fig. 6be combined with all other geometric variations described to achieve the associated advantages.

[0049] A gust of wind hitting the wind turbine, i.e., a change in the speed of the incoming airflow, causes a change in the effective angle of attack on the operating rotor blade 1. The effective angle of attack results from the vectorial addition of the circumferential speed and the incoming wind speed. The ratio of circumferential speed to wind speed thus determines whether a change in the speed of the incoming airflow results in a large or small change in the effective angle of attack.

[0050] At the rotor blade root 2, a gust results in a large change in the effective angle of attack, as the approach velocity is high relative to the peripheral velocity. At the outer blade, near the rotor tip 3, where the peripheral velocity is several orders of magnitude higher and the approach velocity correspondingly significantly lower, the same gust of wind results in only a small change in the effective angle of attack.

[0051] For this reason, it is necessary to design the vortex generators 9 on the inner blade in such a way that they result in the greatest possible angle of attack reserve. This can also be expressed by a desired profile polar that is as free from separation as possible and is the case with a relatively small spacing of the vortex generators 9. The resulting additional drag and the resulting reduced gliding performance are of little significance for the performance of the wind turbine at the low circumferential speeds.

[0052] For the reasons stated above, smaller additional angle of attack reserves are required on the outer blade near the rotor tip 3. Furthermore, excessive drag on the rotor blade 1 at high peripheral speeds would have significantly more negative effects on rotor performance than on the rotor blade root 2. Therefore, in this area, increasing distances between the vortex generators 9 are preferably provided, which, due to lower drag, result in better gliding performance and a somewhat smaller angle of attack extension until stall.

[0053] Alternatively or additionally, the use of smaller vortex generators 9 toward the outside is also expedient, particularly preferably in combination with an increase in the distance to the outside, even if the vortex generators 9 are reduced in size toward the outside. Particularly preferably, the vortex generators 9 are selected from three to five available different sizes of vortex generators 9, so that the complexity, for example, in storage and assembly, remains manageable.

[0054] With regard to the generated sound, the more vortex generators 9 are positioned in the wind, the more sound is generated. Furthermore, the higher the wind speed, the more sound each of the vortex generators 9 generates. A lower density of vortex generators 9 toward the outside compared to the rotor blade root 2 is therefore also preferable from an acoustic perspective.

[0055] The blade design of a rotor blade 1 also aims to maintain the induction factor at the performance-optimal value of 1 / 3 across the radius. Due to the low speed, this is only possible in the area of ​​the rotor blade root 2 by increasing the profile depth, which is only possible to a limited extent for transport reasons, or by increasing the lift coefficients. Therefore, the performance-optimal rotor with a limited maximum depth at the rotor blade root 2 must always be designed to achieve the highest possible lift coefficients in the root area.

Claims

1. A rotor blade (1), with a suction side and a pressure side, for a wind turbine, having: - a rotor blade root (2) of a hub region (I) for attaching the rotor blade (1) to a rotor hub, - a rotor blade tip (3), which is arranged on a side, facing away from the rotor blade root (2), of a tip region (II), - at least one vortex generator (9), which is arranged between the rotor blade root (2) and the rotor blade tip (3), wherein the at least one vortex generator (9) comprises swirl elements (10, 11) with a length (L) and a height (H), which are arranged one next to the other in a longitudinal direction of the rotor blade and are in each case oriented at an angle to a main flow direction (SR) of the rotor blade (1), wherein, in the longitudinal direction of the rotor blade, the swirl elements (10, 11) have a lateral spacing (D, D1) to one another, wherein the vortex generator (9) comprises at least one base plate (13), on which the swirl elements (10, 11) are, in pairs, oriented at an angle to the main flow direction (SR) of the rotor blade (1) that is in each case formed substantially in the opposite direction, wherein the lateral spacing (D, D1) is determined between swirl elements (10, 11) arranged one next to the other at substantially the same angle wherein a variation in the geometry of the swirl elements (10, 11) is realized in a manner dependent on a respective distance (R) between the arrangement of the swirl elements (10, 11) and the rotor blade root (2), characterized in that the variation in the geometry of the swirl elements (10, 11) stems from a ratio (V) of the lateral spacing (D, D1) to the angle to the main flow direction (SR) of the rotor blade (1), which ratio is able to be determined as a function of the distance (R) that increases with increasing distance (R).

2. The rotor blade (1) as claimed in claim 1, characterized in that the variation in the geometry of the swirl elements (10, 11) stems from a ratio (V) of the lateral spacing (D, D1) to the length (L), which ratio is able to be determined as a function of the distance (R).

3. The rotor blade (1) as claimed in one of the preceding claims, characterized in that the variation in the geometry of the swirl elements (10, 11) stems from a ratio (V) of the lateral spacing (D, D1) to the height (H), which ratio is able to be determined as a function of the distance (R).

4. The rotor blade (1) as claimed in one of claims 2 and 3, characterized in that the ratio of the lateral spacing (D, D1) to the length (L) and / or of the lateral spacing (D, D1) to the height (H) increases with increasing distance (R).

5. The rotor blade (1) as claimed in claim 4, characterized in that the length (L) and / or the height (H) of the swirl elements (10, 11) are / is substantially constant.

6. The rotor blade (1) as claimed in one of the preceding claims, characterized in that the swirl elements (10, 11) have a substantially triangular or fin-like profile.

7. The rotor blade (1) as claimed in one of the preceding claims, characterized in that the variation in the geometry of the swirl elements (10, 11) stems from a ratio (V) of the lateral spacing (D, D1) to an internal angle at a tip, at a distance from a surface of the rotor blade (1), of the swirl element (10, 11), which ratio is able to be determined as a function of the distance (R).

8. A wind turbine having a rotor, wherein the rotor has at least one rotor blade (1) as claimed in one of claims 1 to 7.

9. A method for optimizing a wind turbine, wherein the wind turbine has a rotor blade (1), with a suction side and a pressure side, for a wind turbine, wherein the rotor blade has: - a rotor blade root (2) of a hub region (I) for attaching the rotor blade (1) to a rotor hub, - a rotor blade tip (3), which is arranged on a side, facing away from the rotor blade root (2), of a tip region (II), - at least one vortex generator (9), which is arranged between the rotor blade root (2) and the rotor blade tip (3), wherein the at least one vortex generator (9) comprises swirl elements (10, 11) with a length (L) and a height (H), which are arranged one next to the other in a longitudinal direction of the rotor blade and are in each case oriented at an angle to a main flow direction (SR) of the rotor blade (1), wherein the swirl elements (10, 11) have a lateral spacing (D, D1) to one another, wherein the vortex generator (9) comprises at least one base plate (13), on which the swirl elements (10, 11) are, in pairs, oriented at an angle to the main flow direction (SR) of the rotor blade (1) that is in each case formed substantially in the opposite direction, wherein the lateral spacing (D, D1) is determined between swirl elements (10, 11) arranged one next to the other at substantially the same angle wherein a variation in the geometry of the swirl elements (10, 11) is realized in a manner dependent on a respective distance (R) between the arrangement of the swirl elements (10, 11) and the rotor blade root (2), characterized in that the variation in the geometry of the swirl elements (10, 11) stems from a ratio (V) of the lateral spacing (D, D1) to the angle to the main flow direction (SR) of the rotor blade (1), which ratio is able to be determined as a function of the distance (R) that increases with increasing distance (R).