Session: Student Poster Competition

Submission Number: 187063

Coupled Cfd–bem and Structural Load Analysis for Optimal Integration of Active Fluid Gurney Flaps in Wind Energy Systems 

This work examines the Active Fluidic Gurney Flap (AFGF) as an adaptive trailing-edge flow-control concept for wind-turbine blades, with particular emphasis on a multi-level numerical methodology used to evaluate its aerodynamic performance, energetic benefit, and structural-load implications. The AFGF relies on localized jet injection near the trailing edge to actively manipulate the pressure field, enabling controllable lift augmentation without permanent modification of the baseline airfoil. This addresses key limitations of conventional passive Gurney flaps, which lack adaptability and may impose performance penalties outside their design operating range.

The aerodynamic behavior of the AFGF is analyzed using two-dimensional unsteady Reynolds-Averaged Navier–Stokes (URANS) simulations performed on the NREL S809 airfoil, representative of mid-span blade sections in utility-scale wind turbines. Simulations are conducted over a Reynolds number range from 6.0 × 10⁵ to 1.6 × 10⁶ to capture inflow variability typical of wind-turbine operation. Actuation is modeled as discrete trailing-edge jet injections with total pressure levels between 0.5% and 3% above ambient, allowing a systematic investigation of actuation intensity and angle-of-attack dependence.

All simulations are carried out in ANSYS Fluent using the Transition SST turbulence model to resolve laminar–turbulent transition, separation, and reattachment phenomena relevant to wind-turbine airfoils. Wall-resolved meshes with targeted refinement in the boundary layer, jet-exit region, and near wake are employed to accurately capture jet–flow interaction and pressure redistribution. Grid independence is verified through a Grid Convergence Index approach, while second-order spatial discretization and implicit time integration are used throughout. Time-step sensitivity studies ensure convergence of time-averaged aerodynamic coefficients.

Aerodynamic quantities extracted from statistically steady solutions include lift and pitching-moment coefficients, circulation, and surface pressure distributions. In addition, the airfoil center of pressure is evaluated as a function of angle of attack and actuation level, providing direct insight into changes in sectional pitching moments and structural load redistribution induced by active flow control. All AFGF results are benchmarked against both a clean airfoil and a conventional mechanical Gurney flap of comparable height to isolate the benefits of active versus passive devices.

To assess rotor-level implications, the sectional aerodynamic data are incorporated into a Blade Element Momentum (BEM) model representing the central span of a wind-turbine blade. This CFD–BEM coupling enables evaluation of power capture while accounting for changes in aerodynamic loading. A genetic-algorithm-based optimization framework is used to identify actuation strategies that maximize net power output, explicitly accounting for the energetic cost of jet actuation. The results demonstrate that pressure-optimized, spatially targeted AFGF actuation can enhance aerodynamic performance while maintaining controllable load redistribution, highlighting its potential for adaptive, high-performance wind-turbine blade applications.

Presenting Author: Mario Lucas Jerez Universidad Rey Juan Carlos

Presenting Author Biography: Mario Lucas is an aerospace engineer from Rey Juan Carlos University of Madrid. He is currently a PhD Candidate in Aeronautical Engineering at the same institution. Mario also serves as a Research Assistant in the Department of Signal Theory and Communications, Telematic Systems, and Computers. His research focuses on the development of active flow control technologies aimed at improving aerodynamic performance.

Authors:

Mario Lucas Jerez Universidad Rey Juan Carlos
Jorge Saavedra García Universidad Rey Juan Carlos