Abstract
Flow in a channel with distributed surface roughness is considered. Results of the linear stability analysis show that the presence of the roughness destabilizes the traveling-wave instability as well as introduces a new instability that manifests itself in the form of streamwise vortices. The critical conditions for the occurrence of both instabilities are given for different classes of roughness shape. It is shown that these conditions can be predicted with a reasonable accuracy in the case of an arbitrary (but Fourier transformable) roughness by considering only the leading Fourier mode (wavy-wall model). It is argued that the onset of instabilities provides a decision mechanism that determines whether a particular rough wall can be viewed as being hydraulically smooth in the case of transitional flows. © 2006 Elsevier Masson SAS. All rights reserved.
| Original language | English |
|---|---|
| Pages (from-to) | 305-329 |
| Journal | European Journal of Mechanics, B/Fluids |
| Volume | 26 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - May 2007 |
| Externally published | Yes |
Bibliographical note
Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].Research Keywords
- Distributed surface-roughness
- Flow instabilities
- Hydraulically smooth wall