We report on the generation of mono- and polychromatic optical phase singularities from micron-sized birefringent droplets. This is done experimentally by using liquid crystal droplets whose three dimensional architecture of the optical axis is controlled within the bulk by surfactant agents. Because of its microscopic size these optical vortex generators are optically trapped and manipulated a...

Besides its original purpose of reducing wave drag at transonic speed it has been shown that shock control bumps (SCB) can additionally be used for buffet alleviation. Considering 3-D-SCBs as a novel sort of vortex generators these bumps introduce, when carefully designed, streamwise vorticity into the flow and thereby prevent the boundary layer (BL) from early separation. The current paper pre...

The six-dimensional exotic Galilean algebra in (2+1) dimensions with two central charges m and θ, is extended when m = 0, to a tendimensional Galilean conformal algebra with dilatation, expansion, two acceleration generators and the central charge θ. A realisation of such a symmetry is provided by a model with higher derivatives recently discussed in [1]. We consider also a realisation of the G...

this paper is about experimental results for partial reduction of vortex at vertical pipe intakes. one of the easiest and practical ways of reducing vortex effect is to use anti-vortex plates or baffles. these plates can be used to avoid the vortex completely or partially. this paper will concentrate on the latter case. rectangular plates with different dimensions have been placed at different ...

In air-cooling applications with frost production, heat exchanger performance is often air-side limited, because the two-phase flow of the refrigerant provides excellent heat transfer coefficients, and because designers typically use a large air-side fin spacing for frost tolerance. The large fin spacing prolongs operation of the heat exchanger by mitigating the effect of the accumulating frost...