Detached-eddy simulation of turbulent flow over a wiper blade

Abstract

Decreasing noise and improving efficiency is an important trend for the future jetliner industry. The predominant sources of aerodynamic noise are created from attached turbulent boundary layers (TBL) as well as separated flows. The current numerical effort will focus on geometry of a fence to crudely model a windshield wiper blade for a large jetliner. This will produce an unsteady separated flow field. The recent literature lacks some of the characteristics that would make it most useful to aircraft applications. The numerical simulations performed were validated with a backward facing step experiment at M = 0.15. The backstep geometry was then altered one feature at a time until an angled fence system was produced. All simulations except the final were performed with conditions that matched the wind tunnel experiment. The final simulation was performed at cruise conditions at 35,000 feet, with rough flight deck conditions provided by the Boeing Company. The Mach number of the incoming boundary layer flow is 0.5. Results of mean velocity fields were in excellent agreement with experiments. Turbulence intensity as well as pressure quantities agreed. Spectra of pressure fluctuations followed trends of past experiments. Pressure fluctuation magnitudes were over predicted just as many other numerical investigations in literature concluded.