Abstract. If a fluid is electrically conductive, its flow may be controlled using electromagnetic forces. Meanwhile, this technique is a recognized tool even on an industrial scale for handling highly conductive materials like liquid metals. However, also fluids of low electrical conductivity as considered in the present study, like sea-water and other electrolytes, permit electromagnetic flow control. Experimental results on the prevention of flow separation by means of a streamwise, wall parallel Lorentz force acting on the suction side of inclined flat plates and hydrofoils will be presented.

No abstract

This paper presents an approach that predicts the resonant frequency of a high-performance dc servomotor. The correlation between this approach and experimentally determined resonant frequencies is good. The design of the armature, the coupling shafts, and the annular couplers is discussed with regard to maximizing the resonant frequency of the motor.

In HSVA’s medium-sized cavitation tunnel, an LDV-service (Laser Doppler Velocimeter) was used to measure the three-dimensional flow field in the slipstream of different model propellers. Three propellers were investigated with the same main dimensions except for different skew. The propellers were designed especially for this investigation. The skew angles were 0 degrees, 21 degrees and 62 degrees. Most measurements were done at a distance of 0.3 D behind the propellers at uniform inflow.

A direct thermal-to-pneumatic energy converter utilizing the principle of thermal transpiration through a porous membrane is described. The applicability of this no-moving-part pump to a fluidic control system is discussed. A laboratory model has been constructed and experimentally evaluated for several gases, membrane types, and temperature ranges. A theoretical model is derived from the binary diffusion equations of kinetic theory. A linearized version of this model is verified experimentally for small temperature gradients. The kinetic theory model is evaluated numerically to predict the static performance of a pump for large temperature gradients.