Boundary Layer Transition Induced By Surface Roughness Distributed Over a Low-Pressure Turbine Blade
Year: 2026
Type: article
Abstract: Direct numerical simulations of a low-pressure turbine with roughness elements distributed over the blade surface have been performed. A series of 15 cases with varying roughness heights and streamwise wavenumbers is introduced to present a systematic study of the effect of roughness on the various transition phenomena in the suction-side boundary layer. For cases with large roughness heights, the boundary layer is violently disturbed by the wake of roughness elements in the leading edge (LE) region, and maintains a turbulent state over the whole blade suction side. For cases with small roughness heights, however, the disturbances induced by the LE roughness are suppressed by the favorable pressure gradient in the downstream boundary layer, and the relaminarized flow does not undergo transition until the separation near the blade trailing edge (TE). Furthermore, the streamwise wavenumber of the distributed roughness plays an important role in cases with intermediate roughness height. Specifically, cases with larger streamwise slope show earlier transition induced by strong shear layer instability, which manages to suppress the mean flow separation near the TE region. Overall, the combined effect of several factors, including the geometric effect at the blade LE and TE, the complex pressure gradient distribution across the turbine vane, and the various roughness configurations, is responsible for the intriguing boundary layer behaviors in the present study.
Source: Journal of Turbomachinery
DOI: 10.1115/1.4072013
Authors: Xianwen Zhu, Yuchen Ge, Yaomin Zhao, Zuoli Xiao, Richard D. Sandberg
Institutions: Peking University, The University of Melbourne
Language: English
Subfield: Aerospace Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Awards: G1948000921, G8996434041, G995612298
OpenAlex ID: W7162096538