Pressure-Induced Separation of a Laminar Boundary Layer over a Partially-Slip Wall
Abstract
The characteristics of pressure-induced laminar separation bubbles (LSBs) over a partially-slip wall, compared with that over a canonical no-slip wall, are studied using direct numerical simulation. Three cases, two utilizing linear Robin-type slip boundary conditions of differing slip length ($\Lambda$), and one non-slip are compared. For the partial-slip cases, a streamwise distribution of slip profile is employed ensuring smooth transition between no-slip and partial-slip (transition from no-slip to a constant slip length takes 5$\delta$, where $\delta$ is the inflow boundary layer thickness). The constant target slip length is maintained for $20\delta$ upstream and during the onset of flow separation. The separation is induced by a wall-normal velocity profile applied at the top boundary. All cases are performed at $Re_\delta = U_{\infty}\delta/\nu = 455$. Initial results indicate that as slip length increases, separation and reattachment are delayed. Most notably, the formation and shedding of roller vortices is mitigated as slip length increases, resulting in a less turbulent wake, despite that self-similarity of the plane shear layer is maintained.
- Publication:
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arXiv e-prints
- Pub Date:
- August 2024
- DOI:
- 10.48550/arXiv.2408.07008
- arXiv:
- arXiv:2408.07008
- Bibcode:
- 2024arXiv240807008K
- Keywords:
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- Physics - Fluid Dynamics
- E-Print:
- 7 pages, 9 figures