Real-Time Adaptive Control of Mixing in a Plane Shear Layer
Abstract
A control system for the enhancement and regulation of mixing in a nonreactive plane shear layer has been developed in a two-stream closed-return water facility. Mixing of a passive scalar is estimated using a thermal analog in which two streams have uniform, steady temperatures differing by AT = 30 C. The position of the temperature interface between the two streams is measured by an optical sensor which is placed upstream of the initial rollup of the spanwise vortices. Downstream of this sensor cross-stream temperature distributions are measured with an array of 31 cold wire sensors. The actuators are a mosaic of surface film heaters flush mounted on the high-speed side of the flow partition. The degree of mixing between the two streams can be significantly varied with open-loop spanwise-uniform and -nonuniform time-harmonic excitation. In closed-loop experiments and output from the interface position sensor is fed back to the surface heaters. These experiments indicate that feedback control of the motion of the temperature interface can be a powerful means of controlling entrainment by the spanwise vortices and hence effectively controlling mixing downstream of the mixing transition. In related experiments, piezoelectric actuators are developed for the modification and control of free shear flows. A square air jet is forced using four resonantly driven piezoelectric actuators and excitation is effected via amplitude modulation of the resonant carrier-waveform.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1992
- Accession Number
- ADA246948
Entities
People
- A. Glezer
Organizations
- University of Arizona