Active Flow Control Simulations and Experiments for Drag Reduction of an External Stores Support System

A flow control study was conducted on the UH-60 helicopter External Stores Support System (ESSS) to demonstrate drag reduction on full-scale flight hardware at relevant speeds. This study included a coupled computational fluid dynamics (CFD) and experimental approach. Reynolds Averaged Navier-Stokes (RANS) CFD simulations identified the baseline flow patterns and the drag contributions from each component of the ESSS. CFD design tools were then used to determine an improved Active Flow Control (AFC) configuration using steady suction and steady blowing. This AFC configuration was implemented in both a 1/3 scale wind tunnel model and full scale flight hardware tested in a wind tunnel. Drag reduction numerical predictions greater than 12% were validated in both scaled and full-scale wind tunnel tests for freestream velocities up to 100 knots. Net energy efficiency was achieved on the 1/3 scale model for lower drag reduction values at low-level AFC input. This joint effort demonstrated a practical design methodology for development of AFC systems for drag reduction in full-scale applications. The method has yet to be expanded to include unsteady AFC effects, which have the potential of reduced mass-flow and larger energy efficiency.