Considerations for Numerical Modeling of Inverted Wings in Ground Effects

T HE series of experiments conducted by Zerihan [1], Zerihan and Zhang [2,3], and Zhang and Zerihan [4–6] on an 80% scale model of the front wing of the 1998 Tyrell Formula One car (here referred to as the T-026 profile, based on a modified NASA GA(W) LS(1)-0413) have justifiably become the go-to source of validation for researchers investigating single and double element wings in ground effect (for example, [7–13]). This is due to the comprehensive nature of the tests, which included chordwise and spanwise pressure measurements for a large range of angles of attack and ground clearances (in terms of height-to-chord ratio, h=c), flow visuali­ zation, information about turbulent transition, offsurface measure­ ments of wakes, vortices, and the general flowfield using both particle image velocimetry and laser doppler anemometry and force balance data for drag and downforce (negative lift). Subsequent numerical investigations modeling this geometry have tended to focus on two-dimensional geometry representing the semispan point of the full wing (z=b = 0), and several studies have made comparisons between turbulence models and meshes in an attempt to determine the best approach for such flows [7–12]. While the original experiments for the wing detailed three-dimensional effects in considerable detail with regard to vortex behavior, spanwise pressure distributions, etc. [1], the wing had a fixed aspect ratio of 4.92 (corresponding to the real-world Formula 1 wing) and thus the true two-dimensionality of the wing at the semispan was not fully investigated. For this reason, some methodological issues associated with the interpretation of the data in two-dimensional comparisons have not been properly resolved, and to date it is not clear if a truly objective comparison of numerical schemes has been determined. While the influence of aspect ratio and wind-tunnel wall effects are well established for other oft-cited airfoils [14], lifting