Session: 10.4.2 - Vortex Dynamics II

Paper Number: 158048

158048 - Comparison of Delta Wing Vortices in the Near-Wake: Flow Regimes and Methods 

Abstract: 

The iconic flow visualization images of highly swept leading-edge vortex flows, such as Werlé’s ONERA water tunnel studies, have long inspired generations of fluid dynamicists with their aesthetic appeal and the challenge of measuring and characterizing these complex flow fields, particularly in the wake region. Despite this, the state-of-the-art information on wake flows behind delta wings remains predominantly qualitative rather than quantitative. 

The 75° sweptback delta wing offers significant advantages for aircraft operating in both subsonic and supersonic regimes, including enhanced stability and maneuverability at low speeds, and reduced wave drag at supersonic speeds by aligning the leading edge with the Mach cone to minimize shock wave effects. However, the experimental and computational research on 75° sweptback delta wings remains relatively small, often extrapolating findings from other sweep angles to infer aerodynamic characteristics.

This study presents a computational fluid dynamics (CFD) investigation of a 75° sweptback delta wing at angles of attack of 7° and 12°, with a free stream velocity of 8 m/s. Results are validated with the experimental data and flow field visualizations, and subsequently compared with the supersonic experiments conducted at Mach 2.49. The wing model features a flat-top configuration, a 4% thickness-to-root-chord ratio, and 30° chamfered side edges.

The CFD results include skin friction contours on the planform and detailed flow field maps of the total pressure loss coefficient, turbulence intensity, normalized streamwise vorticity, and normalized total velocity at six near-wake locations. Comparisons of skin-friction lines with surface oil flow visualizations highlight the spanwise locations of leeward vortices, confirming topological similarities between the compressible and incompressible regimes. The CFD findings reveal details not accessible through measurements, reinforcing the potential of industrial software for wake-flow analysis.  

This study demonstrates qualitative similarities between high- and low-speed leading-edge vortices, identifies key quantitative differences between flow regimes, and lays the groundwork for future research on supersonic delta wing aerodynamics.

Presenting Author: Jagbir Singh Shergill University of Hartford

Presenting Author Biography: