Original scientific paper
https://doi.org/10.21278/brod75102
On the propeller wake evolution using large eddy simulations and physics-informed space-time decomposition
Zhan Zhang
; Chongqing Southwest Research Institute for Water Transport Engineering, Key Laboratory of Inland Waterway Regulation Engineering, Chongqing Jiaotong University; Chongqing Xike Water Transport Engineering Consulting Co., Ltd
Peng Sun
; Chongqing Southwest Research Institute for Water Transport Engineering, Key Laboratory of Inland Waterway Regulation Engineering, Chongqing Jiaotong University; Chongqing Xike Water Transport Engineering Consulting Co., Ltd
Long Pan
; Bomber and Transport Aircraft Pilots Conversion Department
Teng Zhao
; School of Shipping and Naval Architecture, Chongqing Jiaotong University
Abstract
A novel modal analysis methodology, denoted as the physics informed sparsity-promoting dynamic mode decomposition (pi-SPDMD) model, was introduced for the reduction and reconstruction analysis of intricate propeller wake flows, aiming to provide insight into the inherent flow structures spanning diverse temporal and spatial scales. Large-Eddy Simulation (LES) was employed to numerically model the wake dynamics of a four-bladed propeller, providing a comprehensive resolution from the proximate to the distant wake regions. The findings indicate that the pi-SPDMD model enhances the efficiency of the sparse-promoting algorithm, producing modes that gravitate towards stability, and the resulting decomposition maintains commendable physical fidelity. Integrating the results from the LES solution and the modal decomposition of pi-SPDMD, the tip vortex exhibits a uniform topological configuration with notable coherence in the proximate domain. In this region, the large-scale vortex is the dominant feature of the propeller wake, and there is a marked intermittency in the turbulence. In the mid-field, the tip vortex system transitions into fine-scale vortices, rapidly diminishing in coherence due to the onset of elliptic instability and subsequent secondary vortex generation. As the tip vortex structures related to physical quantities become fully discretized, the small-scale turbulent patterns quickly intermingle, leading to a more homogeneous distribution in the distant wake.
Keywords
LES; Pi-SPDMD; numerical analysis; propeller wakes; tip vortex instability; vorticity
Hrčak ID:
312936
URI
Publication date:
1.1.2024.
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