Waterproof sensor system for simultaneous pressure and hot-film flow measurements
For simultaneous measurement of pressure and near surface flow conditions allowing indirect determination of wall shear stress in experimental water tunnel environment an integrated hybrid sensor system has been developed. In contrast to known approaches, which are limited to the use in gas atmosphere due to protruding electrical and fragile parts, our sensor system is waterproof shielded and embedded in epoxy resin. Furthermore an amplification circuit for the pressure signal based on a programmable gain amplifier is integrated in direct vicinity to the pressure sensor in order to minimize noise by electromagnetic disturbances. Also sensor systems with on-board digitalization of the pressure signal for direct digital read-out were realized. We present all aspects of system assembly and embedding to one waterproof module. Furthermore, read-out strategies as well as sensor test results in air and water are shown and watertightness is confirmed.