DES prediction of a 3-element high-lift airfoil with a blown flap

Ouyang, Bo; Yao, Yufeng; Bouferrouk, Abdessalem

Abstract

Over the last 20 years, research on aerodynamic flow control methods has received considerable attention due to its ability to improve aircraft aerodynamic performance beyond current capabilities (Ternoy et al., 2013). It is evident that a successful implementation of flow control in an aircraft’s high-lift devices can result in various benefits to its performance, such as stall suppression, lift increase and drag reduction (Bright et al., 2013). However active devices such as blowing slots can also produce sophisticated flow phenomena such as turbulent flow mixing, which increase the difficulty in CFD prediction. In particular, when using the Reynolds-Averaged-Navier-Stokes (RANS) approach, discrepancy between CFD results and experimental predictions is very common and sometimes the level of disagreement can be significant (Bright et al., 2013; Ciobaca et al., 2013). Further investigation on high-fidelity CFD method was suggested in order to better predict the performance and to understand the underlying flow physics of such an actively controlled high-lift system. Despite a higher computational cost, it is known that large-eddy simulation (LES) gives more accurate results than RANS especially when dealing with flows involving complex flow physics, such as largely separated or unsteady separated flows. However, recent trends have seen the increased use of detached-eddy simulation (DES) which exploits the strength of LES in predicting separated flows, through incorporating sub-grid scale (SGS) model in the separated flow region away from the wall and turbulence modelling in the near wall attached flow region, to significantly reduce the computational costs while still achieving higher prediction accuracy for complex flows (Choudhari, 2011). Recently, a three-element 30P30N baseline configuration with a steady blown flap was investigated using DES which showed a positive effect on stall suppression (Ouyang et al., 2016), see, e.g. Figure1. The main purpose of the present work is to evaluate the capabilities of the DES method for the same baseline airfoil but with a periodic / pulse blown flap. Further studies will be carried out to identify the effects of changing flow control parameters such as nozzle positions and momentum coefficients in the hope of finding an optimized flow control configuration.

• Presentation Conference Type: Presentation / Talk
• Conference Name: 52nd 3AF International Conference on Applied Aerodynamics
• Start Date: Mar 27, 2017
• End Date: Mar 29, 2017
• Acceptance Date: Mar 29, 2017
• Publicly Available Date: Jun 7, 2019
• Peer Reviewed: Not Peer Reviewed
• Keywords: DES, prediction, 3-element, high-lift, airfoil, blown flap
• Public URL: https://uwe-repository.worktribe.com/output/890642
• Additional Information: Title of Conference or Conference Proceedings : 52nd 3AF Int. Conf. on Applied Aerodynamics