Zweidimensionale kompressible turbulente Grenzschichten Messung und Berechnung des Einflusses der Vorgeschichte auf die Grenzschicht stromab

TIB: RN 6756 (1983,3) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Untersuchung zur Einsetzbarkeit von Miniatur-Drucksensoren fuer die Messung instationaerer Druecke in Stroemungsmaschinen

Measurements of pressure variations in the source region are to be conducted in conjunction with an investigation of sound generation mechanisms on axial flow turbomachinery. The capacitor microphones normally used in acoustic measuring techniques cannot be used universally because of their volume. In addition, there are plans to measure pressure variations at the blade tips of a rotating impeller. The use of capacitor microphones might be problematic due to centrifugal accelerations (> 1000 g) present there. Piezoelectric or piezoresistive transducers offer themselves as candidate pressure sensors. While silicon sensors today are becoming smaller and smaller and more complex, their operational performance is increasing. The objective of the investigation was to determine the quality of a variety of pressure sensors as compared to that of capacitor microphones under suitable acoustic sound applications (free field, pressure chamber and with flow). Commercially available miniature pressure sensors - e.g. piezoresistive sensors made by KULITE, or IC sensors, or even piezoelectric films (PVDF) - obviously have been used for acoustic measurements only little or not at all. Their main advantages over capacitor microphones are their considerably smaller external dimensions. The behavior of different sensors with respect to amplitude, frequency and phase position were to be determined and assessed. (orig./AKF)Available from TIB Hannover: RR 4148(89/B3) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

A note on the instability of a vortex sheet leaving a semi-infinite plate

SIGLETIB: RN 437 (87-16) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman