| Status | 已發表Published |
| In Search of the Dominant Free Surface Fluctuation Frequency Downstream of the Oscillating Hydraulic Jump with the Bayesian Spectral Density Approach | |
Mok, K. M. ; Yuen, K. V.; Cheong , K. H. ; Hoi, K. I.
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| 2011-08-01 | |
| Source Publication | Abstracts of the Proceedings of the Third International Conference Turbulent Mixing and beyond
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| Pages | 24-24 |
| Publication Place | Trieste |
| Publisher | The Abdus Salam International Centre for Theoretical Physics |
| Abstract | Oscillating hydraulic jump is a particular open-channel flow phenomenon characterized by its abrupt increase in water depth due to the rapid transition from the supercritical to subcritical flow with the inflow Froude number existing between 2.5 and 4.5. The most distinct features of the oscillating jump are its formed turbulent surface roller and the wavy downstream free surface. Previous studies found that this wavy surface should have periodic fluctuation with its signature left in the measured energy spectrum of the surface fluctuation, which has the main trend of an approximately bell-shaped curve but is shadowed with obvious fluctuating spikes (Mok, 2004; Mossa, 1999; Murzyn and Chanson, 2009). Based on the concept proposed by Mok (2004) that the dominant frequency was caused by the periodic generation and advection of the turbulent eddies released from the surface roller and their interactions with the free surface downstream, the present study sets out to model this process with a single-degree-of-freedom (SDOF) system and identify the dominant frequency with the Bayesian spectral density approach (Katafygiotis et al., 2001; Yuen, 2010). This study is the first of its kind since the optimal estimates of the dominant frequencies and their corresponding uncertainties could be estimated without imposing any engineering judgment from the noisy spectra. In this study, a numerical example was employed to demonstrate the proposed methodology. In addition, the validated Bayesian approach was further applied to estimate the dominant frequencies based on the measured energy spectra of the free-surface fluctuation at the jump end for six cases of oscillating jumps with inflow Froude numbers ranging from 2.63 to 3.62. It was found that the main trend of the measured spectrum in each case could be well captured by the modeled one with the identified parameters; hence confirming the validity of the proposed methodology in application. |
| Keyword | Bayesian spectral density hydraulic jump surface fluctuation surface roller |
| Language | 英語English |
| The Source to Article | PB_Publication |
| PUB ID | 48381 |
| Document Type | Conference paper |
| Collection | HENRY FOK PEARL JUBILEE COLLEGE |
| Corresponding Author | Mok, K. M. |
| Recommended Citation GB/T 7714 | Mok, K. M.,Yuen, K. V.,Cheong , K. H.,et al. In Search of the Dominant Free Surface Fluctuation Frequency Downstream of the Oscillating Hydraulic Jump with the Bayesian Spectral Density Approach[C], Trieste:The Abdus Salam International Centre for Theoretical Physics, 2011, 24-24. |
| APA | Mok, K. M.., Yuen, K. V.., Cheong , K. H.., & Hoi, K. I. (2011). In Search of the Dominant Free Surface Fluctuation Frequency Downstream of the Oscillating Hydraulic Jump with the Bayesian Spectral Density Approach. Abstracts of the Proceedings of the Third International Conference Turbulent Mixing and beyond, 24-24. |
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