David R. Williams, PhD

AFOSR - Active Control of Acoustic Tones in Aircraft Cavities

Aircraft are limited in the flight speed at which weapons bay cavities can be opened, because of the large amplitude acoustic resonances that develop. This project is aimed at preventing acoustic resonances in aircraft cavities by using active control. Pressure sensors detect the onset of resonant oscillations, which are cancelled by acoustic actuators. This technology may impact the noise in wheel well cavities on commercial aircraft.

Rockwell Science Center - Measurements of Stores Released from Weapons Bay Cavities

Releasing stores from internal weapons bay cavities has been a somewhat unpredictable process leading to large variability in store trajectories. The problem can be traced to the interaction between the store and the large oscillations in the shear layer present over the cavity. Researchers at Rockwell Science Center have developed new models for predicting the trajectories based on asymptotic methods. Experiments are being conducted in the IIT NDF wind tunnel to document the trajectories of generic models that are released from a cavity, in order to test the validity of the theory.

Acoustics Activities

The phenomenon of sonoluminescence is being studied experimentally in search of the mechanism leading to light production from concentrated acoustic waves. Acoustic beam-forming techniques are under investigation as a method to determine the key noise-producing elements from the CTA elevated train.