Pasternack1 Received 23 February ; revised 7 April ; accepted 1 May ; published 23 September However, most studies utilizing classical hydraulic jump relationships have neglected the role of aerated flows and jump types prevalent in natural systems.
Waterfalls Overview The interaction between flow, sediment transport, and channel morphology is very poorly known for bedrock rivers. A key foci for channel change in such rivers is the bed step.
Despite their prevalence, the role of bed steps on river flow mechanics, sediment transport, channel change, and basin evolution has been hardly investigated at all, primarily because of adverse site conditions that previously limited field data collection.
The overall goal of this line of research has been to overcome past constraints on investigating the fluid mechanics in the vicinity of waterfalls of all sizes and its relevance to fluvial geomorphology.
This is being done with the aid of new technologies that enable precise in situ measurement for the first time. New technologies developed and tested at UC Davis include a patented River Truss system, an air content sensor for studying the hydraulic jump at the base of falls, a 3D force sensor, and differential pressure transducers with high-frequency response.
These new technologies are being used to address hypotheses regarding bedrock river morphology, universal waterfalls systematics, the dynamics associated with individual types of bed steps.
A better understanding of the role of waterfalls in channel change is very important to science because it would improve the physics of landscape evolution models, provide needed guidance for including in-stream features in river restoration, and make interdisciplinary contributions to ecology and aquatic geochemistry.
In future research, other scientists will be able to apply the newly proven field technologies and resulting models to better understand the complex flow mechanics and channels interactions occurring in mountain rivers. Please select specific topical areas from the list below to learn more about the specific research activities that have been done as part of this program.
Field mapping and digital elevation modelling of submerged and unsubmerged hydraulic jump regions in a bedrock step-pool channel.
Earth Surface Processes and Landforms Air concentrations of submerged and unsubmerged hydraulic jumps in a bedrock step-pool channel, Journal of Geophysical Research Submerged and unsubmerged natural hydraulic jumps in a bedrock step-pool mountain channel.
Convergent hydraulics at horseshoe steps in bedrock rivers.
Jet and hydraulic jump near-bed stresses below a horseshoe waterfall, Water Resources Research 43, W, doi: Modeling energy dissipation and hydraulic jump regime responses to channel nonuniformity at river steps. Journal of Geophysical ResearchF, doi:Sep 20, · This video shows lab experiments about measuring bed shear stress in free and submerged hydraulics jumps using a Preston tube.
Experiments and video was produced by the following postgraduate.
While this analogue has been applied to unsubmerged jumps of varying sizes in natural channels [e.g., Kieffer, ; Carling, ], it has also been applied to submerged jumps in step‐pool settings [e.g., Parker and Izumi, ].
There are a myriad of ways to prevent a submerged hydraulic jump from forming, however most solutions have serious drawbacks. Some points to consider when designing a retrofit include: cost, safety, energy dissipation, scour, sediment deposition, variable flow, fish passage, effects on headwater depth, and ice passage.
The experiment showed that hydraulic jumps happen when a high velocity liquid enters a zone of lower velocity.
The approach used by the group is controlled volume method, as it is the most commonly used approach in analyzing hydraulic jumps. Read "Submerged and unsubmerged natural hydraulic jumps in a bedrock step-pool mountain channel, Geomorphology" on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
High-resolution digital elevation models (DEMs) for natural submerged and unsubmerged jump regions were tested against the classical hydraulic jump (CHJ) and engineering analogues that have.