This dissertation analyzes the effect of periodic roughness elements on the stability
of a flat plate boundary layer. Receptivity data is extracted from direct numerical
simulations and experimental data and the results are compared to theoretical predictions.
This analysis shows that flow in the immediate vicinity of roughness elements is
non-linear; however, the evolution of roughness-induced perturbations is a linear phenomena.
New techniques are developed to calculate receptivity information for cases
where direct numerical simulations are not yet possible. Additionally, the stability
behavior of the roughness wake is analyzed. New instability modes are found, and
the effect of boundary layer complexity, perturbation amplitude and other factors are
examined. It is shown that the wake is much less stable than optimal perturbation
theory predicts, and highlights the importance of receptivity studies. The implication
of these results on transition-to-turbulence is discussed, and future work is proposed.
T
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2011-05-9192 |
| Date | 2011 May 1900 |
| Creators | Denissen, Nicholas Allen |
| Contributors | White, Edward |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | thesis, text |
| Format | application/pdf |
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