Abstract: A method and a device suitable for carrying out the method are proposed for analyzing and quantifying flows, in particular for the three-dimensional determination of flow velocity components or the three-dimensional visualization of flows in fluids or gases. For this purpose, electromagnetic waves, especially light, are detected, which at least partially emanate from or are scattered by particles that are contained in the detection space and that characterize the flow to be analyzed, the waves being detected using at least one detection device, in the form of two-dimensional images that are recorded in a frequency-selective or frequency-band-selective manner, from which the flow is determined. The illuminating device for this purpose generates at least two, at least approximately parallel light sheets, arranged in spatial succession, generated in temporal succession, having electromagnetic waves of different frequencies or different frequency spectrums, which scan the detection space at least in areas.

Abstract: A process and apparatus are disclosed for generating object traces representing the movement of objects through a measuring space. The measuring space can be illuminated by a laser or other light source, or alternatively the objects can be self-illuminating. In either event, light from the objects is detected over a finite acquisition time, to generate the object traces. During a predetermined portion of the acquisition time, preferably near the end, one of several parameters that govern the object trace width is altered to increase the width, thereby giving the object trace the form of an arrow or vector. The altered parameter can be the brightness of illumination, the sensitivity of the image detector, or the position or state of system components, in particular the image detector, a lens or other active optical component between the objects and the detector, or an optical component between the light source and the objects.

Abstract: The invention concerns a method and device for determining the aerodynamic diameter of particles carried in a flow. To that end, the velocity of the flow is altered in an area and the particle velocity measured at at least one point before said area and at at least one point in or after said area. Owing to the alteration of the flow velocity, the particles carried in the flow are with increasing aerodynamic diameter retarded or accelerated increasingly more slowly than the carrier fluid, depending on whether an area of flow retardation or flow acceleration is concerned. Knowing the constraints makes it possible, therefore, by measuring the particle velocity in or shortly after this area of altered flow velocity, to infer the aerodynamic diameter.