Leading Edge Oscillatory Blowing: Influence on Subsonic Cavity Flow and Application in Synchronized Dynamic Store Separation
Abstract
The objective of the research was twofold: first, investigate the effect of leading-edge flow control on subsonic (Mach < 0.13) flow fields over a rectangular cavity (L/D = 4.465), and second, develop the capability to synchronize store release with an oscillatory leading edge blowing device's position and identify any trends in forces and moments imparted on the store. The active flow control method utilized a linear motor oscillating at 5.0 Hz to provide leading edge blowing. Five different leading edge devices were designed and characterized: a single channel Slot and four fluidic diodes. The study used the AFIT low-speed wind tunnel in combination with a tri-axial velocity probe to gather time-accurate data for all three velocity components. Flow control methods were compared using measurements of growth in the shear layer, turbulence intensity, and spatial representation of secondary flows. Compared to the Slot, the fluidic diode designs increased shear layer thickness and displaced it toward the freestream. A second linear motor was used to move the store from 0.75 inches below the cavity lip line to 2.25 inches above the lip line. Two initialization positions were tested: the oscillatory linear motor either fully retracted or fully extended. Synchronization between the motors was successfully accomplished using in-situ position readouts from the high-resolution digital encoders in each linear motor and visually with a high-speed digital camera. A dedicated data acquisition system incorporating a Nano-25 balance, collecting data at 1000 Hz, provided time-accurate measurements of the forces and moments acting on the store before, during, and after trajectory motion. The oscillatory blowing was observed to influence the normal force component within the shear layer prior to store motion.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2018
- Accession Number
- AD1056663
Entities
People
- Matthew L. Wood
Organizations
- Air Force Institute of Technology