Turbulent Boundary Layer in a 3-Element High-LiftWing: Coherent Structures Identification

TL;DR

This study uses large-eddy simulation to analyze the turbulent boundary layer on a high-lift wing, identifying coherent structures and comparing boundary layer characteristics to classical models.

Contribution

It provides detailed LES analysis of a high-lift wing's turbulent boundary layer, highlighting the presence of streaks and energy distribution across modes.

Findings

Boundary layer exhibits zero-pressure-gradient characteristics.

TBL streaks are identified and linked to energetic structures.

Energy is spread across higher-order POD modes.

Abstract

A wall-resolved large-eddy simulation (LES) of the fluid flow around a 30P30N airfoil is conducted at a Reynolds number of Rec=750,000 and an angle of attack (AoA) of 9 degrees. The simulation results are validated against experimental data from previous studies and further analyzed, focusing on the suction side of the wing main element. The boundary layer development is investigated, showing characteristics typical of a zero-pressure-gradient turbulent boundary layer (ZPG TBL). In particular, the boundary layer exhibits limited growth, and the outer peak of the streamwise Reynolds stresses is virtually absent, distinguishing it from an adverse-pressure-gradient turbulent boundary layer (APG TBL). A proper orthogonal decomposition (POD) analysis is performed on a portion of the turbulent boundary layer, revealing a significant energy spread across higher-order modes. Despite this, TBL streaks are identified, and the locations of the most energetic structures correspond to the peaks in the Reynolds stresses.