3D flow in the venom channel of a spitting cobra: do the ridges in the fangs act as fluid guide vanes?

The spitting cobra Naja pallida can eject its venom towards an offender from a distance of up to two meters. The aim of this study was to understand the mechanisms responsible for the relatively large distance covered by the venom jet although the venom channel is only of micro-scale. Therefore, we analysed factors that influence secondary flow and pressure drop in the venom channel, which include the physical-chemical properties of venom liquid and the morphology of the venom channel.

In vitro experimental investigation of voice production.

The process of human phonation involves a complex interaction between the physical domains of structural dynamics, fluid flow, and acoustic sound production and radiation. Given the high degree of nonlinearity of these processes, even small anatomical or physiological disturbances can significantly affect the voice signal. In the worst cases, patients can lose their voice and hence the normal mode of speech communication.

Experimental flow study of modeled regular and irregular glottal closure types.

The present study shows the results of visualization experiments of the jet formation through a dynamic model of the human vocal folds. The model consists of two counter-rotating, 3D-shaped driven cams covered with a stretched silicone membrane. The 3D contours of the cams are a result of an optimized mapping of observed characteristic clinical vocal fold motions.

Three-dimensional nature of the glottal jet.

The factors contributing to human voice production are not yet fully understood. Even normal human phonation with a symmetric glottal opening area is still the subject of extensive investigation. Among others, it has already been shown that fluid dynamics has a strong influence on the vocal process.

Investigation of the washout effect in a magnetically driven axial blood pump.

For a long-term implementation of the magnetically driven CircuLite blood pump system, it is extremely important to be able to ensure a minimum washout flow in order to avoid dangerous stagnation regions in the gap between the impeller and the motor casing as well as near the pivot-axle area at the holes in the impeller's hub. In general, stagnation zones are prone to thrombus formation. Here, the optimal impeller/motor gap width will be determined and the washout flow for different working conditions will be quantitatively calculated.

Computational fluid dynamics and digital particle image velocimetry study of the flow through an optimized micro-axial blood pump.

A detailed knowledge of the flow field in a blood pump is indispensable in order to increase the efficiency of the pump and to reduce the shear-induced hemolysis. Thus, three different impeller designs were developed and tested by means of computational fluid dynamics (CFD) and digital particle image velocimetry (DPIV). The results show a good agreement of CFD and DPIV data.