A device for lacquer transfer includes a frame, a transfer roller with a circumferential lateral wall, a drive unit and a lacquer application unit. The lacquer application unit is mounted on the frame and applies lacquer to a work surface of a work piece while the device is moved in an application direction across the work surface. The drive unit drives the transfer roller in a rotation direction about an axis of rotation. An outside contact surface of the lateral wall comprises a plurality of depressions forming a predetermined structure. The transfer roller rolls with the outside contact surface on the work surface of the work piece for transferring the predetermined structure defined by the depressions in the outside contact surface to lacquer previously applied to the work surface by the lacquer application unit.

The present invention relates to a bullet with an increased effective range. The bullet includes a front end portion (10) having a hemispherical shape, a recess portion (20) connected to a rear end of the front end portion (10) and having a curved surface that is recessed inward, an inclined portion (30) connected to a rear end of the recess portion (20) and inclined at a predetermined angle (A) with respect to a horizontal line, a stepped portion (40) connected to a rear end of the inclined portion (30) and inclined at a predetermined angle (A) with respect to the horizontal line, and fluid inducing grooves formed from the rear to a rear end surface of the bullet (1). Thus, when the bullet passes through underwater, super cavitation may be more effectively generated and maintained for even longer to significantly increase the effective range of the bullet.

A magnetic insertion meter is disclosed herein. Disclosed insertion meters include in some examples, a sensor head tube cylinder having a textured front surface and at least two electrodes. Disclosed insertion meters include a textured front surface adapted to move the separation point of a fluid flowing over the sensor head tube towards the upstream surface as compared to the same sensor head tube without the textured front surface. Methods of measuring flow are also disclosed herein using example magnetic insertion meters.

A rowing oar is described. The rowing oar can have a plurality of flow disrupters arranged on a shaft of the oar. In one embodiment, the flow disrupters can be circular bumps arranged in lines along the shaft of the oar. The flow disrupters can cause the air flow over the oar to be more turbulent so that the flow separation on a backside of the oar is reduced. The reduction in flow separation can reduce aerodynamic drag on the oar when it travels through the air. Thus, a rower can expend less energy during rowing using the oar.

A microstructured surface with microfeatures formed thereon and defining spaces between the microfeatures includes least one electrode of an electrode pair in the spaces, wherein electrodes of the pair are electrically connected to one another. The at least one electrode located in the space is configured to generate a gas in between the microfeatures when an electrolyte solution penetrates into the microfeatures. Importantly, the electrodes are not connected to any external power source. Because the microstructured surface is self-powered in replenishing the gas lost in a submerged condition, no additional provision to supply energy or regulate the replenishment is necessary for implementation and use.

The invention pertains to the use of an easy-to-clean soft fiber-coated material on the underwater surface of structures to mimic mammal pelage and as such reducing residual drag, wherein said material comprises or consists of fibers having an average fiber length between 0.3 and 4 mm, and an average fiber thickness between 5 and 80 m. The underwater surface of structure is preferably the hull of a movable or moving vessel, or the underwater part of a static structure such as offshore wind monopiles and off-shore rigs. In some embodiments, the invention pertains to the reduction of fuel consumption of a nautical vessel passing through water.

A coating apparatus for the reduction of aerodynamic noise and vibrations. The coating apparatus is configured to include a group of fibrillar structures, wherein each fibrillar structure is configured with a diverging tip so that the coating reduces the size of and shifts downstream, a separation bubble, and modulates large-scale recirculating motion. Each fibrillar structure can be configured as a cylindrical micropillar. The group of fibrillar structures can be configured as a group of uniformly distributed cylindrical micropillars (e.g., one or more micropillar arrays). The surface coating is effective in reducing the separation bubble and displacing the separation bubble downstream. The coating facilitates a reduction in noise (e.g., aerodynamic noise) and vibrations due to the reduction in the size of the separation bubble.

A phononic material includes an interface surface and a subsurface feature mechanically connected to the interface surface. When a hypersonic flow having at least one instability flows past the interface surface, the interface surface vibrates in response to one or more frequency components of the pressure. The interface surface couples each frequency component into the subsurface feature, which at least partially reflects and phase-shifts each frequency component to generate a corresponding phase-shifted frequency component. The interface surface vibrates in response to the phase-shifted frequency component, thereby coupling the phase-shifted frequency component back into the hypersonic flow. The phase-shifted frequency component interferes with said each frequency component within the hypersonic flow. The subsurface feature may perform phase-shifting such that the phase-shifted frequency component destructively interferes with said each frequency component, thereby reducing the at least one instability.

A magnetic insertion meter is disclosed herein. Disclosed insertion meters include in some examples, a sensor head tube having a textured front surface and at least two electrodes. Disclosed insertion meters include a textured front surface adapted to move the separation point of a fluid flowing over the sensor head tube towards the upstream surface as compared to the same sensor head tube without the textured front surface. Methods of measuring flow are also disclosed herein using example magnetic insertion meters.

A novel mechanism for reducing boundary layer friction and inhibiting the effects of uncontrolled fluid turbulence and turbulent layer separation, thus reducing the body drag, kinetic energy losses and lowering engine and pump fuel consumption is proposed. It steps on the type of turbulence observed in the so-called in fluid dynamics drag crisis. Plurality of device shapes and plurality of devices producing the wanted pure form of even plurality of counter-rotating vortices extending into the flow, i.e. tubes, are presented and discussed in detail, contrasting with the prior art. Configurations of multiple devices for the purposes of drag and fuel reduction, including their simulations and experimental results are put forward. Additional embodiments of the resulting tubes disclose use on aircraft or vessel control surfaces as stall inhibitors, use in wind turbines as dynamic range extenders, as well as use in turbines in efficient cooling mechanisms.