A flow control device on a structure such that strain in the structure is at least partially transferred to the flow control device is disclosed having at least two states, or shapes, separated by an elastic instability region. The flow control device is arranged to rapidly transition, or snap through, from the first state to the second state when strain in the structure exceeds an activation threshold of the flow control device. A spoiler on an aerofoil may have a rest position where it is substantially flush with the low pressure surface and an activated position where it protrudes from the low pressure surface and modifies the airflow over that surface. The spoiler bends to move from the rest position to the activated position when the strain in the aerofoil crosses a threshold. The deployed spoiler reduces the lift on the aerofoil, acting to reduce the lift induced strain of the aerofoil to which the spoiler is attached.

Provided is a wind turbine blade for a wind turbine, including a web extending along a longitudinal direction of the blade, an electrically conductive beam extending along the longitudinal direction of the blade and being connected to the web, a lightning conductor extending along the longitudinal direction of the blade and being attached to the web, and a ply including carbon fibers, wherein the ply is attached to both the lightning conductor and the beam to electrically connect the lightning conductor to the beam. This has the advantage that an extensive and a continuous electrical connection between the lightning conductor and the beam is provided and that a plurality of cables electrically connecting the lightning conductor with the beam may be substituted.

A flow control device on a structure such that strain in the structure is at least partially transferred to the flow control device is disclosed having at least two states, or shapes, separated by an elastic instability region. The flow control device is arranged to rapidly transition, or snap through, from the first state to the second state when strain in the structure exceeds an activation threshold of the flow control device. A spoiler on an aerofoil may have a rest position where it is substantially flush with the low pressure surface and an activated position where it protrudes from the low pressure surface and modifies the airflow over that surface. The spoiler bends to move from the rest position to the activated position when the strain in the aerofoil crosses a threshold. The deployed spoiler reduces the lift on the aerofoil, acting to reduce the lift induced strain of the aerofoil to which the spoiler is attached.

A system for storing and generating power is disclosed. The system comprises a first storage reservoir configured to store a first fluid, a second storage reservoir located at a lower elevation than the first storage reservoir and configured to store a second fluid wherein said second fluid has a higher density than the first fluid, and a pump. The pump and the first and the second reservoir are operatively connected such that power is stored by displacing the second fluid in the second storage reservoir by pumping the first fluid from the first storage reservoir to the second storage reservoir and such that power is generated by allowing the pumped first fluid in the second storage reservoir to exit the second reservoir. The first fluid is generally a liquid. In some embodiments, a power recovery device may be employed. In some embodiments, the hydraulic pressure of the low density fluid may be employed to pressurized desalination feed and facilitate desalination.

A method of manufacturing a rotor blade component for a rotor blade of a wind energy installation, a rotor blade component, and a wind energy installation comprising such a rotor blade component. The method includes manufacturing a layer system including a first layer of a first material and a second layer of a second material. The second material has a smaller modulus of elasticity than the first material, and the second layer extends at least partially along the first layer. The layer system is beveled at least at one end with the aid of at least one separation process such that the second layer projects beyond the first layer at the at least one end of the layer system. The layer system is connected to at least one other such layer system so as to form the rotor blade component.

The present application pertains to systems and methods for storing and generating power. In one embodiment the system pertains to a first storage reservoir near the surface of a body of water and configured to store a fluid which has a lower density than water. A second storage reservoir is located below the surface of the body of water and configured to store a fluid which has a higher density than water. A pump, generator, and the first and second reservoir are operatively connected such that power is stored by displacing the fluid which has a higher density than water in the second storage reservoir by pumping the fluid which has a lower density than water in the first storage reservoir to the second storage reservoir. Power is generated or discharged by allowing the fluid which has a lower density than water in the second storage reservoir to return to the first storage reservoir. The fluid which has a higher density than water may be in liquid form.

A wind turbine blade bushing system for arrangement in a root end of a wind turbine blade is described. The wind turbine blade bushing system comprises a threaded element for retaining a mounting bolt for a wind turbine blade, the threaded element being formed from a first material; and an anchor element for arrangement at the root end of the wind turbine, wherein the anchor element acts to at least partly retain the threaded element in the wind turbine blade, the anchor element being formed from a second material. The first material has a higher strength and higher fracture toughness than the second material.

Provided herein are passive microfluidic pumps. The pumps can comprise a fluid inlet, an absorbent region, a resistive region fluidly connecting the fluid inlet and the absorbent region, and an evaporation barrier enclosing the resistive region, the absorbent region, or a combination thereof. The resistive region can comprise a first porous medium, and a fluidly non-conducting boundary defining a path for fluid flow through the first porous medium from the fluid inlet to the absorbent region. The absorbent region can comprise a fluidly non-conducting boundary defining a volume of a second porous medium sized to absorb a predetermined volume of fluid imbibed from the resistive region. The resistive region and the absorbent region can be configured to establish a capillary-driven fluid front advancing from the fluid inlet through the resistive region to the absorbent region when the fluid inlet is contacted with fluid.

The present application pertains to systems and methods for storing and generating power. In one embodiment the system pertains to a first storage reservoir near the surface of a body of water and configured to store a fluid which has a lower density than water. A second storage reservoir is located below the surface of the body of water and configured to store a fluid which has a higher density than water. A pump, generator, and the first and second reservoir are operatively connected such that power is stored by displacing the fluid which has a higher density than water in the second storage reservoir by pumping the fluid which has a lower density than water in the first storage reservoir to the second storage reservoir. Power is generated or discharged by allowing the fluid which has a lower density than water in the second storage reservoir to return to the first storage reservoir. The fluid which has a higher density than water may be in liquid form.

Provided herein are passive microfluidic pumps. The pumps can comprise a fluid inlet, an absorbent region, a resistive region fluidly connecting the fluid inlet and the absorbent region, and an evaporation barrier enclosing the resistive region, the absorbent region, or a combination thereof. The resistive region can comprise a first porous medium, and a fluidly non-conducting boundary defining a path for fluid flow through the first porous medium from the fluid inlet to the absorbent region. The absorbent region can comprise a fluidly non-conducting boundary defining a volume of a second porous medium sized to absorb a predetermined volume of fluid imbibed from the resistive region. The resistive region and the absorbent region can be configured to establish a capillary-driven fluid front advancing from the fluid inlet through the resistive region to the absorbent region when the fluid inlet is contacted with fluid.