Session: 31-11 Boundary Layer Dynamics

Paper Number: 152886

Unsteady Boundary Layer Behavior Due to Wake Passing Effects on Low-Speed Linear Cascade Compressor Airfoils With Single and Tandem Configurations: Part 1 - Midspan Flow 

This study numerically investigates the unsteady boundary layer behavior of highly loaded compressor airfoils in single and tandem configurations, subjected to wake-passing effects in a low-speed linear cascade with contracting endwalls. The influence of periodic disturbances, generated by an upstream cylindrical wake generator, is analyzed at various flow coefficients and Strouhal numbers using unsteady numerical simulations with DLR’s CFD solver TRACE, employing a rotation-corrected k−w turbulence model and the gReTH transition model.

Results show that both configurations exhibit wake-induced transition, with the front vane of the tandem stator behaving similarly to the single stator. However, the rear vane is primarily influenced by the wake of the cylinder convecting along the pressure side of the front vane, while the suction-side wake branch is shielded, reducing unsteady effects and boundary layer losses. Calmed regions stabilize the boundary layer and delay transition, but increased wake-induced turbulence leads to higher entropy generation and overall airfoil losses, particularly at higher bar speeds.

The study confirms that low bar speeds still capture key unsteady effects, enabling reduced mechanical loading in experiments. While the URANS simulations successfully resolve characteristic boundary layer features, the results remain preliminary and serve as a foundation for comparison with high-fidelity simulations and experimental validation.

Presenting Author: Lukas Reisinger Technical University of Munich

Presenting Author Biography: Lukas Reisinger earned his master’s degree in aerospace engineering in 2022 and is currently a research associate and doctoral candidate at the Institute of Turbomachinery and Flight Propulsion at the Technical University of Munich. His research focuses on developing innovative blade designs for highly loaded compressors, with a particular emphasis on transition modeling and boundary layer laminarization. Lukas aims to enhance compressor efficiency and performance by advancing the understanding of both steady and unsteady aerodynamic effects on boundary layer behavior.

Authors:

Lukas Reisinger Technical University of Munich
Philippe Bieli Technical University of Munich
Volker Gümmer Technical University of Munich