Scaling of the Flow over a Conformal Vortex Generator with a Laminar Boundary Layer

A novel low-profile flow control device, termed conformal vortex generator (CVG), was recently developed as a flow control device that has been shown to reduce fuel consumption on commercial aircraft. The CVG is a three dimensional backwards facing step with height on the order of the boundary layer thickness. The primary fluid mechanisms responsible for the fuel savings are an open research topic. The focus of the current study is to investigate CVG scaling parameters with a laminar boundary layer inlet condition. A proposed scaling law is presented based on simple geometric and flow parameters. The scaling law is tested at flight scale on a general aviation aircraft (Piper Arrow) using wall shear stress visualization and laboratory scale in a water tunnel with two-dimensional, two component particle image velocimetry. Comparisons between the two scales are consistent with the proposed scaling law.