Abstract: The invention is based on the objective of preventing cavitation on streamlined bodies which are immersed in a liquid (2) at high relative speed (v), permitting their use within wider speed ranges. To this purpose, in a transverse slot (4) a two-phase mixture of air and water is produced, which forms a two-phase mixture layer (9) downstream of the slot (4). The required air is supplied from an external source or precipitated from the air contained in the water in the transverse slot. Even without any air at all a water/water-vapor mixture layer is generated, which behaves in the manner of a two-phase mixture layer on account of the finely distributed vapor bubbles. The Reynold's number derived from the width of the slot (4) is greater than 20′000 .

Abstract: In a wing with a main wing part (1) and a drag-reducing wing grid arranged at a distal end of the main wing part, a grid includes at least two winglets (2) staggered in parallel and with an overlap (c/t) smaller than one. A zero air flow direction of the winglets (2) is, on average, matched to the zero air flow direction of the main wing part (1) and the ratio of the length of the chord (cM) of the main wing part (1) to the chord length (cW) of the wing grid is essentially the same as the correction factor Kappa according to Betz applicable for the overlap of the winglets. For this wing, the lift of the main wing part (1) and the wing grid is not only equal in the design point, but also the lift gradients of the main wing part (1) and of the wing grid are coincident. This means that the drag-reducing effect of the wing grid is maintained independent of the momentary angle of attack of the wing, without the wing grid having to be adjusted accordingly.

Abstract: In a wing with a main wing part (1) and a drag-reducing wing grid arranged at the distal end of the main wing part, the grid comprises at least two winglets (2) staggered in parallel and with an overlap (c/t) smaller than one, the zero air flow direction of the winglets (2) is on average matched to the zero air flow direction of the main wing part (1) and the ratio of the length of the chord (cM) of the main wing part (1) to the chord length (cW) of the wing grid is essentially the same as the correction factor Kappa according to Betz applicable for the overlap of the winglets. For this wing, the lift of the main wing part (1) and the wing grid is not only equal in the design point, but also the lift gradients of the main wing part (1) and of the wing grid are coincident. This means that the drag-reducing effect of the wing grid is maintained independent of the momentary angle of attack of the wing, without the wing grid having to be adjusted accordingly.

Abstract: A wing with a wing span (b) has a main part (1), which has a substantially closed surface with respect to the flow (v) and is provided at its free end with an end section in the form of a wing grid. The wing grid has at least two parallel-staggered winglets (2). The wing grid as part of the wing span (b) takes over the intended profile circulation at the attachment point to the main part and subdivides that circulation approximately uniformly over the winglets. The same lift is produced in the end section with the at least two winglets. Thus, for the wing the spanwise lift distribution is more regular and the induced resistance is decreased. An upper or lower limit for the action is obtained as a function of whether, as a result of the fixed wing grid for the entire wing, a rectangular circulation distribution is produced or only for the part of the overall span replaced by the wing grid.

Abstract: A sewage sludge-irradiation device for irradiating sewage sludge with radiation having a sterilizing effect. A conveyor system embodies at least two conveyor devices, at least one of which conveyor device is supplied with a layer of sewage sludge. The conveyor devices are arranged in a manner to form therebetween a passageway defining a mixing gap for the through-passing sewage sludge. A relative movement exists between the two conveyor devices, and radiation means cooperates with the conveyor system for irradiating the sewage sludge at a location prior to intermixing thereof in the mixing gap. The conveyor devices can be driven to possess respectively different speeds of movement, and it is also possible for one of the conveyor devices to be driven and the other to be stationary so as to define a stationary boundary means or surface for the mixing gap.

Abstract: An electro-optical liquid-crystal display device is disclosed which retains its contrast even when viewed through an intervening plane polarizer. This objective is achieved by supplementing the plane polarizer on the viewing side of the display device with a .lambda./4 layer such that the plane polarizer together with the .lambda./4 layer form a circular polarizer.