Investigation of Backward-Facing-Step Flow Field for Dynamic Interface Application

Abstract

A research program to investigate helicopter downwash and frigate airwake interaction has been initiated using a statistically robust experimental program featuring design of experiments. Engineering analysis of the helicopter/frigate interface is complicated by the fact that two flow fields become inherently coupled as a separation distance decreases. The work presented was performed in the Old Dominion University 7 × 8 ft Low-Speed Wind Tunnel using a simplified 1/50-scale frigate waterline model and traverse-mounted powered rotor with thrust measurement capability. Particle image velocimetry velocity surveys were acquired with rotor thrust coefficient measurements at coincident locations to help understand the underlying flow physics.