Control of airflow about a high energy laser turret.

Abstract

A high energy laser system inflicts damage on a target by radiating large amounts of thermal energy onto a small area. Airflow about the laser turret, which is located on top of the aircraft fuselage, is unsteady and causes problems in beam control. The problems are jitter, which is vibration of the laser beam, and optical path distortions. The theory of flow around a cylinder and around a sphere was examined, and several airflow control techniques were screened in an effort to suppress the unsteadiness of the flow. A fairing and turret base suction apparatus was selected and experimentally tested in a wind tunnel. During the course of the experiments several parameters were varied as follows: blower flow rate, spacing between turret and fairing nosepiece, and flow rate in five separate ducts. Results of the tests indicate that the fairing and base suction technique eliminates the unsteadiness. Further research and testing are required to develop the technique for actual use on aircraft.