Wind turbine rotor blade with two rows of vortex generators

A wind turbine rotor blade comprising:

• a rotor blade body having a blade root, a blade tip, a leading edge, and a trailing edge;
• a first row of vortex generators;
• a second row of vortex generators;
• said first row of vortex generators and said second row of vortex generators extending in a spanwise direction;
• said first row of vortex generators being arranged closer to said leading edge than said second row of vortex generators;
• said first row of vortex generators including a first vortex generator defining a first longitudinal axis extending in a chordwise direction and a second vortex generator defining a second longitudinal axis extending in a chordwise direction;
• said first vortex generator and said second vortex generator being mutually adjacent;
• said first vortex generator including a first fin and a second fin arranged symmetrically to the first longitudinal axis;
• said second vortex generator including a third fin and a fourth fin arranged symmetrically to the second longitudinal axis;
• each of said first fin, said second fin, said third fin, and said fourth fin having a respective leading end and a respective trailing end;
• said trailing ends of said first fin and said second fin being arranged at a distance d to each other;
• said distance d being greater than a distance between said leading end of said first fin and said leading end of said second fin;
• the first longitudinal axis and said second longitudinal axis being arranged at a distance D from each other and mutually defining a center line extending in a chordwise direction;
• said second row of vortex generators including a fifth fin having a fifth fin leading end and a fifth fin trailing end, wherein said fifth fin trailing end is arranged closer to the center line than said fifth fin leading end;
• said fifth fin being positioned in relation to said first fin, which is arranged on a same side of the center line as said fifth fin, with said fifth fin trailing end closer to the center line than said fifth fin leading end such that said fifth fin trailing end is arranged at a chordwise distance c from said trailing end of said first fin;
• wherein a distance x of said fifth fin trailing end from the center line is within a range between
• (i) an upper limit xU defined by:
• xU ≤ 0.30 D
• for c > 1.43 D − 3.57 d
• xU ≤ D/2 − d/2 − 0.14 c
• for c ≤ 1.43 D − 3.57 d;
• and,
• (ii) a lower limit xL defined by
• xL ≥ 0.07 D
• for c > 0.75 D − 0.87 d
• xL ≥ D/2 − d/2 − 0.58 c
• for c ≤ 0.75 D − 0.87 d.