Wake Stabilization and Force Modulation via Surface Dimples on an Airfoil at Low-Reynolds-Numbers
Fuente:
arXiv
Salvato in:
| Autori principali: | , , |
|---|---|
| Natura: | Preprint |
| Pubblicazione: |
2025
|
| Soggetti: | |
| Accesso online: | |
| Tags: |
Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
|
| _version_ | 1866909713894998016 |
|---|---|
| author | Sudarsana, Putu Brahmanda Singh, Jagmohan Sareen, Anchal |
| author_facet | Sudarsana, Putu Brahmanda Singh, Jagmohan Sareen, Anchal |
| contents | This study investigates the effect of surface dimples on the unsteady aerodynamics of a National Advisory Committee for Aeronautics airfoil (NACA0012) at a chord-based Reynolds numbers of $Re_c = 5300$ and $10{,}000$ using direct numerical simulations. Dimples were placed on the suction side at non-dimensional chordwise locations of $l_D/c = 0.035$ and $0.35$, and the flow response was studied at a fixed angle of attack $α= 5^\circ$. At $Re_c = 5300$, dimples placed at $l_D/c = 0.35$ reduced lift and drag fluctuations by $26.5\%$ and $33.3\%$, respectively, with minimal change in mean forces. At $Re_c = 10{,}000$, the same configuration led to a seven-fold increase in force fluctuations, while the mean remained unchanged. The smooth airfoil exhibited irregular, aperiodic force signals at this $Re_c$, whereas the dimpled case showed highly periodic behavior, indicating wake stabilization. Flow visualizations revealed that dimples generate streamwise vortices within the boundary layer. These vortices are found to have a stabilizing effect on wake dynamics at $Re_c = 5300$, reducing vortex breakdown and enhancing the coherence of wake structures. Spectral Proper Orthogonal Decomposition (SPOD) showed that dimples redistribute modal energy depending on Reynolds number: at low $Re_c$, they reduce broadband content and suppress unsteadiness, while at high $Re_c$, they amplify dominant shedding modes and broaden the spectral energy distribution. These results demonstrate that dimples can passively modulate unsteady forces and wake dynamics for a flow over a streamlined body, either suppressing or enhancing flow instabilities depending on the regime. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_23564 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Wake Stabilization and Force Modulation via Surface Dimples on an Airfoil at Low-Reynolds-Numbers Sudarsana, Putu Brahmanda Singh, Jagmohan Sareen, Anchal Fluid Dynamics This study investigates the effect of surface dimples on the unsteady aerodynamics of a National Advisory Committee for Aeronautics airfoil (NACA0012) at a chord-based Reynolds numbers of $Re_c = 5300$ and $10{,}000$ using direct numerical simulations. Dimples were placed on the suction side at non-dimensional chordwise locations of $l_D/c = 0.035$ and $0.35$, and the flow response was studied at a fixed angle of attack $α= 5^\circ$. At $Re_c = 5300$, dimples placed at $l_D/c = 0.35$ reduced lift and drag fluctuations by $26.5\%$ and $33.3\%$, respectively, with minimal change in mean forces. At $Re_c = 10{,}000$, the same configuration led to a seven-fold increase in force fluctuations, while the mean remained unchanged. The smooth airfoil exhibited irregular, aperiodic force signals at this $Re_c$, whereas the dimpled case showed highly periodic behavior, indicating wake stabilization. Flow visualizations revealed that dimples generate streamwise vortices within the boundary layer. These vortices are found to have a stabilizing effect on wake dynamics at $Re_c = 5300$, reducing vortex breakdown and enhancing the coherence of wake structures. Spectral Proper Orthogonal Decomposition (SPOD) showed that dimples redistribute modal energy depending on Reynolds number: at low $Re_c$, they reduce broadband content and suppress unsteadiness, while at high $Re_c$, they amplify dominant shedding modes and broaden the spectral energy distribution. These results demonstrate that dimples can passively modulate unsteady forces and wake dynamics for a flow over a streamlined body, either suppressing or enhancing flow instabilities depending on the regime. |
| title | Wake Stabilization and Force Modulation via Surface Dimples on an Airfoil at Low-Reynolds-Numbers |
| topic | Fluid Dynamics |
| url | https://arxiv.org/abs/2507.23564 |