12,000

We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK

93%

93% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > Laboratory measurements of flow and turbulence ...
View graph of relations

« Back

Laboratory measurements of flow and turbulence in discontinuous distributions of ligulate seagrass.

Research output: Contribution to journalJournal article

Published

Journal publication date1/07/2007
JournalJournal of Hydraulic Engineering
Journal number7
Volume133
Number of pages11
Pages750-760
Original languageEnglish

Abstract

Turbulent flow characteristics were investigated in laboratory flume studies of a ligulate plant canopy interrupted by a gap representing discontinuities observed in seagrass prairies. The reliability of velocity measurements obtained using an acoustic Doppler velocimeter within the canopy was shown using specifically designed experiments. In relatively fast flow (mean velocity 5.5 cm s−1), the mean flow profile was logarithmic above the canopy, had an inflection point near its top, and uniformly low values within it. Within the gap, a recirculation cell formed. Reynolds stress maxima were approximately coincident with the mean flow inflection point. Quadrant analysis revealed an ejection-dominated upper layer, a sweep-dominated region around the top of the canopy and within the gap, and no dominant quadrant within the canopy. In slower flow (mean velocity 1.7 cm s−1) the plants were quasiemergent and the flow fields more uniform. Sweeps similarly dominated the region near the top of the canopy and within the gap. In both flows, autocorrelation of longitudinal velocity fluctuations showed a Lagrangian time scale maximum at the downstream end of the gap.

Bibliographic note

AF's roles: formulated the idea, co-led the discussion and interpretation of results, wrote a significant portion of text. RAE_import_type : Journal article RAE_uoa_type : Earth Systems and Environmental Sciences