Various embodiments of an airfoil and machines with airfoils are disclosed. The airfoils include a thicker leading airfoil portion and a thinner trailing airfoil portion. In one embodiment, the leading airfoil portion is formed by bending a body of the airfoil back toward itself. In another embodiment, the leading airfoil portion has a solid geometry and includes two elliptic surfaces. To prevent detachment of airflow, the leading airfoil portion includes at least two arc portions or surfaces that act to direct the airflow down to the trailing airfoil portion in a manner that stabilizes vortexes that may form in the region of changing thickness.

Various embodiments of an airfoil and machines with airfoils are disclosed. The airfoils include a thicker leading airfoil portion and a thinner trailing airfoil portion. In one embodiment, the leading airfoil portion is formed by bending a body of the airfoil back toward itself. In another embodiment, the leading airfoil portion has a solid geometry and includes two elliptic surfaces. To prevent detachment of airflow, the leading airfoil portion includes at least two arc portions or surfaces that act to direct the airflow down to the trailing airfoil portion in a manner that stabilizes vortexes that may form in the region of changing thickness.

A profiled element used is disclosed for generating a force, the profiled element comprising a material having an active surface; a plurality of cavities located on the active surface of the material, the plurality of cavities comprising pin holes, each pin hole having an opening of a micrometric size on the active surface and a depth of a micrometric size greater than its diameter; wherein each pin hole is hermetically sealed on the opposite side of the cavity; and further wherein an airflow circulation against the active surface of the material causes a pressure change on the active surface and inside each of the plurality of cavities thereby generating a force.

A flow modifying device comprises an outer shell, a central tube within an interior space of the outer shell, and a plurality of helix vanes within the interior space. The central tube extends along at least a portion of a length of the outer shell. Each of the helix vanes extend along the outer shell and along the central tube. An outer edge portion of each of the helix vanes is attached to the outer shell and an inner edge portion of each of the helix vanes is located within a central passage of the central tube. In this manner, a first portion of each of the helix vanes extends between the outer shell and the central tube and a second portion of each of the helix vanes is located within the central passage of the central tube.

Various embodiments of an airfoil and machines with airfoils are disclosed. The airfoils include a thicker leading airfoil portion and a thinner trailing airfoil portion. In one embodiment, the leading airfoil portion is formed by bending a body of the airfoil back toward itself. In another embodiment, the leading airfoil portion has a solid geometry and includes two elliptic surfaces. To prevent detachment of airflow, the leading airfoil portion includes at least two arc portions or surfaces that act to direct the airflow down to the trailing airfoil portion in a manner that stabilizes vortexes that may form in the region of changing thickness.

Provided is a filtering apparatus configured to interact with objects of interest within a medium. The properties of the filtering apparatus can be configured to modify the trajectory of individual objects of interest which interact with the filtering apparatus within several orders of magnitude of the mean free path of objects of interest. Surfaces of a filtering apparatus can be constructed to preferentially redirect objects of interest in a desired direction, such as a direction substantially parallel to a surface, or substantially along the length of a channel connecting two reservoirs. This can modify the net diffusion of objects of interest relative to the surface, which can modify the bulk fluid flow velocity magnitude along the surface. This can be employed to reduce the viscous drag on a surface moving relative to a fluid, or to generate thrust, or to convert thermal energy of a fluid into useful work.

Various embodiments of an airfoil and machines with airfoils are disclosed. The airfoils include a thicker leading airfoil portion and a thinner trailing airfoil portion. In one embodiment, the leading airfoil portion is formed by bending a body of the airfoil back toward itself. In another embodiment, the leading airfoil portion has a solid geometry and includes two elliptic surfaces. To prevent detachment of airflow, the leading airfoil portion includes at least two arc portions or surfaces that act to direct the airflow down to the trailing airfoil portion in a manner that stabilizes vortexes that may form in the region of changing thickness.

Various embodiments of an airfoil and machines with airfoils are disclosed. The airfoils include a thicker leading airfoil portion and a thinner trailing airfoil portion. In one embodiment, the leading airfoil portion is formed by bending a body of the airfoil back toward itself. In another embodiment, the leading airfoil portion has a solid geometry and includes two elliptic surfaces. To prevent detachment of airflow, the leading airfoil portion includes at least two arc portions or surfaces that act to direct the airflow down to the trailing airfoil portion in a manner that stabilizes vortexes that may form in the region of changing thickness.

A structural component for a vehicle has a surface with a riblet structure. The riblet structure includes a plurality of grooves, including a first groove having a first longitudinal section forming a first angle with a main longitudinal direction of the structural component. The first angle is larger than 0 and the main longitudinal direction corresponds to a flow direction of a fluid along the surface of the structural component.

Various embodiments of an airfoil and machines with airfoils are disclosed. The airfoils include a thicker leading airfoil portion and a thinner trailing airfoil portion. In one embodiment, the leading airfoil portion is formed by bending a body of the airfoil back toward itself. In another embodiment, the leading airfoil portion has a solid geometry and includes two elliptic surfaces. To prevent detachment of airflow, the leading airfoil portion includes at least two arc portions or surfaces that act to direct the airflow down to the trailing airfoil portion in a manner that stabilizes vortexes that may form in the region of changing thickness.