Direct numerical simulation of flow separation behind a swept, rearward-facing step at ReH=3000
| Autor: | H.-J. Kaltenbach, Gerd Janke |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Fluid Flow and Transfer Processes
Physics Turbulence Mechanical Engineering Computational Mechanics Direct numerical simulation Reynolds number Laminar flow Mechanics Condensed Matter Physics Instability Laminar flow reactor Physics::Fluid Dynamics symbols.namesake Flow separation Classical mechanics Mechanics of Materials symbols Mean flow |
| Zdroj: | Physics of Fluids. 12:2320-2337 |
| ISSN: | 1089-7666 1070-6631 |
| DOI: | 10.1063/1.1287338 |
| Popis: | The effect of sweep on a transitional separation bubble behind a backward-facing step is investigated using direct numerical simulation (DNS). The Reynolds number based on step height and free stream component normal to the step, Reα=(HC∞ cos α)/ν, is kept constant at 3000 for sweep angles α between 0° and 60°. Results agree well with two experimental investigations. Up to α=40°, the mean flow follows the sweep-independence principle. For higher sweep angles, the size of the separated flow region is shortened considerably which is mainly due to an upstream shift of transition in the laminar shear layer emanating from the step and—to a lesser degree—to an increase in turbulent momentum flux uv¯. Fluctuations of wall-stress and wall pressure are largest near the reattachment location and their magnitude scales with (C∞ cos α)2 for all sweep angles. Transition is dominated by a Kelvin–Helmholtz-type instability of the free shear layer. The influence of skewing on the growth rate of instability waves is weak ... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|