Technical Support Package for LAR-13311: Continuous Multi-Element Hot-Film Transition Gage

Abstract

Installed on a laminar flow surface, the continuous multi-element hot-film transition gage provides boundary layer transition information in the streamwise direction. The gage allows simultaneous measurement of stagnation or attachment line position aligred in the streamwise direction with the transition measurement. With this gage, detailed studies are possible concerning the effects of three dimensional flow fields on laminar flow behavior. Thus, the gage provides a unique means for acquiring accurate boundary layer data in situations where sensing instruments must be installed on the exterior of a test surface. The gage performs the functions of previous systems with greater simplicity and saves time, space, and cost for laminar boundary layer data acquisition systems. The electronic circuitry allows switching of elements into the servo control loop at faster rates than was previously possible. The electronic MOSFET switch provides a very low resistance which will remain repeatable throughout the aging of the circuit, and the switch will not be affected by vibration, accelerations, oxidation or life cycle. The rapid switching speed permits significantly more data to be gathered than prior art circuitry.