Fluid Turbine Rotor Blade with Winglet Design

The rotor blade of claim one further comprising:

• said first winglet is at least 30% longer than said second winglet;
• and
• a rotor swept area providing a rotor plane having a center and a perimeter;
• and
• said first winglet is comprised of an airfoil profile having a lift surface facing toward the center of the rotor plane and a pressure surface facing away from the center of the rotor plane;
• and
• said second winglet comprised of an airfoil profile having a lift surface facing away from the center of the rotor plane and a pressure surface facing toward the center of the rotor plane.
• wherein, the winglet airfoils, being in opposite directions with respect to each other's lift and pressure surfaces, create counter rotating vortices in the wake of the rotor plane thus mixing relatively higher energy fluid into the relatively low energy wake of the rotor.

A rotor blade for a fluid turbine comprising:

• an upwind direction;
• and
• a downwind direction;
• and
• a root region;
• and
• a tip region;
• and
• a body extending from said root region to said tip region;
• and
• said body further comprising an airfoil cross section, said airfoil cross section comprising:
• a leading edge;
• and
• a trailing edge;
• and
• a lift surface;
• and
• a pressure surface;
• and
• said leading edge transitioning into a fork shape having a first leading-edge fork direction and a second leading-edge fork direction;
• and
• said first leading-edge fork direction turning arcuately in said downwind direction;
• and
• said second leading-edge fork direction turning arcuately in said upwind direction;
• and
• said trailing edge transitioning into a fork shape having a first trailing-edge fork direction and a second trailing-edge fork direction;
• and
• said first trailing-edge fork direction turning arcuately in said downwind direction;
• and
• said second trailing-edge fork direction turning arcuately in said upwind direction;
• wherein
• said fork shape having a first fork, and a second fork;
• and
• said first fork shape and said second fork shape each having a lift surface and a pressure surface;
• and
• said lift surface of said first fork shape facing the opposite direction of said lift surface on said second fork shape.

The rotor blade of claim five wherein

• said rotor plane has a center and a perimeter, the center proximal to the root of the rotor blades, the perimeter proximal to the a region past the tip of the rotor blades;
• and
• said first leading-edge fork direction turning arcuately in said downwind direction transitions to a lift surface that faces toward the center of the rotor plane;
• and
• said second leading-edge fork direction turning arcuately in said upwind direction transitions to a lift surface that faces toward the perimeter of the rotor plane.

A rotor blade for a fluid turbine comprising:

• an upwind direction;
• and
• a downwind direction;
• and
• a root region;
• and
• a tip region;
• and
• a body extending from said root region to said tip region;
• and
• a vertical centerline proximal to the center of gravity of any cross section of said body extending from said root region past said tip region;
• and
• said body further comprising an airfoil cross section, said airfoil cross section comprising:
• a leading edge;
• and
• a trailing edge;
• and
• a lift surface;
• and
• a pressure surface;
• and
• a winglet fixedly engaged with said body, proximal to said tip region;
• and
• said winglet having an arcuate shape that is tangent to a plane that is perpendicular to said vertical centerline at the point of engagement with said body;
• and
• said winglet having a first arcuate extension and a second arcuate extension;
• and
• said first arcuate extension extending in a down-wind direction;
• and
• said second arcuate extension extending in an upwind direction;
• and
• both arcuate extensions swept away from said leading edge of said body.

The rotor blade of claim seven wherein;

• said first arcuate extension of said winglet having an airfoil cross section;
• and
• said airfoil cross section on said first arcuate extension having a lift surface and a pressure surface;
• and
• said lift surface on said first arcuate extension of said winglet facing toward the center of the rotor plane;
• and
• said second arcuate extension of said winglet having an airfoil cross section;
• and
• said airfoil cross section on said second arcuate extension having a lift surface and a pressure surface;
• and
• said lift surface facing toward the perimeter of said rotor plane;
• wherein the lift surface of the first arcuate extension directs flow in rotating vortices that begin in a direction toward the center of the rotor plane and the lift surface of the second arcuate extension directs flow in rotating vortices that begin in a direction toward the perimeter of the rotor plane, the two sets of vortices being counter rotating.

A rotor blade for a fluid turbine comprising:

• an upwind direction;
• and
• a downwind direction;
• and
• a root region;
• and
• a tip region;
• and
• a body extending from said root region to said tip region;
• and
• said body further comprising an airfoil cross section, said airfoil cross section comprising:
• a leading edge;
• and
• a trailing edge;
• and
• a lift surface;
• and
• a pressure surface;
• and
• said lift surface facing in said downwind direction;
• and
• said pressure surface facing in said upwind direction;
• and
• a centerline proximal to the center of gravity of each cross section along said body and extending from said root region past said tip region;
• and
• a rotor plane provided by the swept area of said rotor blade, the center of the rotor plane proximal to said root region and the perimeter of the rotor plane proximal to said tip region;
• and
• a forked winglet transitioning from said lift surface of said body, and said fork having at least two prongs, at least a first prong and at least a second prong;
• and
• said at least first and said at least second prong curving arcuately away from said centerline in a downwind direction;
• and
• said at least first and said at least second prong each having an airfoil cross section, first and second prong-airfoil having a leading edge and a trailing edge;
• and
• first and second prong-airfoil cross sections having a lift surface facing the center of the rotor plane and a pressure surface facing the perimeter of the rotor plane;
• and
• said first and second prong-airfoil cross sections having trailing edges that are further from said rotor plane center than said first and second prong-airfoil cross section leading edges;
• wherein
• flow through the rotor plane is directed by said forked winglet in a bell shape downwind of said rotor plane creating an expanding wake region where wake-flow expands into.

A rotor blade for a fluid turbine comprising:

• an upwind direction;
• and
• a downwind direction;
• and
• a root region;
• and
• a tip region;
• and
• a body extending from said root region to said tip region;
• and
• said body further comprising an airfoil cross section, said airfoil cross section comprising:
• a leading edge;
• and
• a trailing edge;
• and
• a lift surface;
• and
• a pressure surface;
• and
• said lift surface facing in said downwind direction;
• and
• said pressure surface facing in said upwind direction;
• and
• a centerline proximal to the center of gravity of each cross section along said body and extending from said root region past said tip region;
• and
• a rotor plane provided by the swept area of said rotor blade, the center of the rotor plane proximal to said root region and the perimeter of the rotor plane proximal to said tip region;
• and
• said tip region comprising a first winglet and a second winglet;
• and
• said first winglet extending arcuately away from said lift surface in said downwind direction;
• and
• said first winglet having an airfoil cross section with said lift surface facing toward the center of the rotor plane;
• and
• said second winglet extending arcuately away from said pressure surface in said upwind direction;
• and
• said second winglet having an airfoil cross section with the lift surface facing away from the center of the rotor plane while the second winglet extends arcuately away from said pressure surface;
• and
• said second winglet continuing to curve arcuately in the downwind direction;
• and
• as the second winglet curves arcuately in the downwind direction, the airfoil cross section of said second winglet transitions to an airfoil cross section with a lift surface facing the center of the rotor plane;
• wherein
• flow through the rotor plane is directed by said forked winglet, first in opposing rotating vortices and then in a bell shape downwind of said rotor plane providing mixing of high speed flow into the rotor wake while creating an expanding wake region where wake-flow expands into.

The rotor blade of claim fifteen further comprising:

• said first winglet extending arcuately away from said lift surface in said downwind direction at an angle that is between 70° and 120° with respect to the vertical centerline;
• and
• said second winglet extends arcuately away from said pressure surface in an upwind direction at an angle that is between 15° and 35° with respect to the vertical centerline;
• and
• said second winglet continuing to curve arcuately in the downwind direction at an angle that is between 75° and 95° with respect to the vertical centerline.

The rotor blade of claim fifteen;

• wherein
• the airfoil cross section at the end of the first and second winglet comprises a leading edge and a trailing edge;
• and
• said leading edge of said first winglet is closer to the center of the rotor plane than the trailing edge of said first winglet;
• and
• said leading edge of said second winglet is closer to the center of the rotor plane than the trailing edge of said second winglet.