Device mountable on a surface (10), the device comprising a spacer system (12, 16, 20, 22) and a grid structure (2) which grid structure (2) is attached in spaced relation to the surface (10) by means of the spacer system (12, 16, 20, 22), wherein the distance between the surface (10) and the grid structure (2) is in a range from >0.1 m to <10 mm, wherein the grid structure (2) forms meshes of a mesh size in a range from >0.5 m to <8 mm, and wherein the surface of the grid structure (2) is at least partially amphiphobic. Method of maintaining a gas or air layer on a surface when the surface is immersed in a liquid or water comprising such device, and uses thereof.

A spoiling apparatus for triggering a turbulent transition by autonomous disturbance and spoilers. The spoilers are mounted in multiple grooves in the circumferential direction of a navigating body, when a flow autonomously undergoes a turbulent transition, the spoilers remain in the grooves, the surface of the navigating body is free of protrusion, thus causing no additional flow resistance. A rated critical Reynolds number is set, in a case of a reduced flow speed and reduced density, the flow is a laminar flow, at which time the pressure applied to the spoilers by the flow is reduced, and the spoilers are ejected under the effect of compression springs. When ejected, the spoilers disturb the flowing of the bottom layer of the flow, and trigger the laminar flow into a turbulent flow. By setting the rebounding force of the compression springs, the spoiling apparatus is turned on automatically when a disturbance-triggered turbulent transition is required and is turned off when not required, thus implementing the autonomous control of turbulent transitions.

The invention relates to a cover device for at least sectional closing of an underwater opening in a hull of a watercraft, in particular an opening of a transverse channel of a thruster. According to the invention the cover device includes at least one variable-volume hollow chamber lip including at least one buoyancy body, and the at least one hollow chamber lip is shiftable into an expansion state or into a shrinkage state by supplying or removing a fluid, in particular air. As a result of the variable-volume or inflatable cover device a more reliable and simultaneously lower-maintenance operation of the cover device is given. In addition, the invention has a thruster, in particular a bow or stern-thruster, as subject matter.

The invention relates to a cover device for at least sectional closing of an underwater opening in a hull of a watercraft, in particular an opening of a transverse channel of a thruster. According to the invention the cover device includes at least one variable-volume hollow chamber lip including at least one buoyancy body, and the at least one hollow chamber lip is shiftable into an expansion state or into a shrinkage state by supplying or removing a fluid, in particular air. As a result of the variable-volume or inflatable cover device a more reliable and simultaneously lower-maintenance operation of the cover device is given. In addition, the invention has a thruster, in particular a bow or stern-thruster, as subject matter.

The invention provides a solution for inadequate boundary layer testing methods. The invention includes a uniquely configured multi-module concentric loop cycling water past a testing module to obtain real-time values and variables to use in CFD calculations. The invention is comprised of various sections, specifically designed to support the entire system. The system includes: one or more water reservoirs/degassing tanks, high-capacity water pumps, water stream straightener(s), stable flow section, air induction ports, viewing ports, test modules containing test surfaces designed to measure friction and pressure of a passing water or air/water stream. The present invention includes one or more sensors on the test surface(s) that convey conditions to one or more computers that may receive, store, process and send interpretations to one or more visual monitors on or near the invention in real time.

The invention provides a solution for inadequate boundary layer testing methods. The invention includes a uniquely configured multi-module concentric loop cycling water past a testing module to obtain real-time values and variables to use in CFD calculations. The invention is comprised of various sections, specifically designed to support the entire system. The system includes: one or more water reservoirs/degassing tanks, high-capacity water pumps, water stream straightener(s), stable flow section, air induction ports, viewing ports, test modules containing test surfaces designed to measure friction and pressure of a passing water or air/water stream. The present invention includes one or more sensors on the test surface(s) that convey conditions to one or more computers that may receive, store, process and send interpretations to one or more visual monitors on or near the invention in real time.

Aerodynamic microstructures having sub-microstructure are disclosed herein. One disclosed example apparatus includes an aerodynamic microstructure on an external surface of a vehicle, and sub-microstructures superimposed on the aerodynamic microstructure, where the sub-microstructures are spaced to reduce reflections.

Aerodynamic microstructures having sub-microstructure are disclosed herein. One disclosed example apparatus includes an aerodynamic microstructure on an external surface of a vehicle, and sub-microstructures superimposed on the aerodynamic microstructure, where the sub-microstructures are spaced to reduce reflections.

The invention relates to a vessel for operating on a body of water comprising: a non-planing hull having a waterline and a longitudinal direction with a forward portion, an aft portion, and a central portion, the hull being configured to have the aft portion with a smaller water displacement relative to a water displacement at the central portion; and an aft foil affixed to the aft hull portion with one or more connecting members, and below the surface of the water, and spaced from the hull, the aft foil having a span, a chord, and a leading edge and a trailing edge relative to a forward direction, wherein the leading edge of the aft foil is tilted at a downward angle relative to the horizontal, wherein the aft foil has a chord and profile in longitudinal cross section, with a configuration to provide a lifting force, the tilt angle of the chord of the aft foil being measured with respect to the horizontal, and wherein the aft foil is oriented to provide a continuous, upward, forwardly directed component of the lifting force.

A floating structure for transport is presented, formed by a train arrangement of rotary bodies of revolution that reduces the drag of same during sailing, the train arrangement of rotary bodies being formed by a front body, intermediate bodies and a rear body that have rotation synchronized with the speed of travel of the structure, the intermediate bodies of revolution being connected together by longitudinal rotation shafts by connections secured to an upper platform, while the longitudinal rotation shafts of the front body and the rear body are connected to the rotation shafts of adjacent bodies by hinges, which are pivotably connected to an end of draft-adjustor, pivotably connected at their other ends to the upper platform, the longitudinal rotation shafts being disposed perpendicular to the structure's travel direction and associated with actuators. The rotary bodies are separated by a distance of approximately 5% or less of their diameter.