Experimental and LES investigations of horseshoe vortex characteristics in wall-mounted rectangular cylinders for various angles of incidence
To examine the flow characteristics of horseshoe vortices (HV) in wall-mounted rectangular cylinders, surface oil-flow visualization and Large Eddy Simulation (LES) were used for experimental and numerical studies, respectively. This research examined various incident angles relative to the approach...
Saved in:
| Published in: | Ocean engineering Vol. 315; p. 119810 |
|---|---|
| Main Authors: | , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Elsevier Ltd
01-01-2025
|
| Subjects: | |
| Online Access: | Get full text |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | To examine the flow characteristics of horseshoe vortices (HV) in wall-mounted rectangular cylinders, surface oil-flow visualization and Large Eddy Simulation (LES) were used for experimental and numerical studies, respectively. This research examined various incident angles relative to the approaching flow (LES: α = 0°–45°, oil-flow visualization: α = 0°–90°) and cross-sectional aspect ratios (CR = 1–4) for Reynolds numbers of (12−48)×103. The features of HV have been analyzed, and the critical points (saddle and focal) and their relationships to physical phenomena have been evaluated. The presence of two saddle points (S1 and S2) and their associated nodes (N1 and N2) confirms the formation of two regions in the horseshoe vortices. The region closer to the upstream of the cylinder experiences higher shear stress than that farther away. It was observed that two focal points appear behind the cylinders, which show the positions of arch-shaped vortex legs that meet the bottom surface. Three patterns of horseshoe vortices were identified based on the focal point positions for various α and CR. The focal points in pattern I are symmetric with respect to the streamwise direction, where their spacing is less than the width of the cylinder. In pattern II, the focal points lose symmetry, forming on one side of the cylinder very close to each other. The positions of focal points in pattern III become asymmetric with respect to the streamwise direction. In addition, the width of the HV region and the reattachment point on the cylinder surface were examined for different CR and α. The reattachment point occurs at the junction between cylinders and wall for CR = 4 at α = 0°–15°, CR = 3 at α = 5°–15°, CR = 2 at α = 10°–15°, and CR = 1 only at α = 15°.
•Investigation of incidence angles and aspect ratios for flow over wall-mounted rectangular cylinders.•Using surface oil-flow visualization and Large Eddy Simulation for flow analysis.•Classifying critical points and their roles on the vortex structures.•Three flow patterns of horseshoe vortices are introduced.•Evaluating how reattachment flow influences on the vortex width. |
|---|---|
| ISSN: | 0029-8018 |
| DOI: | 10.1016/j.oceaneng.2024.119810 |