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Experiments by Invited Researchers

 

Experiments on vertical motions of rotating flows over variable topography

Project acronym: HyIII-CNRS-26
Name of Group Leader: G. van Heijst, Eindhoven University of Technology,
User-Project Title: Experiments on vertical motions of rotating flows over variable topography
Facility: Coriolis platform
Proceedings TA Project: Experiments on vertical motions of rotating flows over variable topography
Data Management Report: There is no Data Management Report available for this project

User-Project Objectives

Summary:

This project seeks to gain a better understanding of vertical displacements in a rotating fluid interacting with topographic features. Although vertical motions at meso and large scales in the oceans are usually one order of magnitude smaller than horizontal displacements, they play a fundamental role on a large number of oceanic processes by transporting physical, biological and chemical properties. In particular, aggregations of plankton are frequently observed over shelf breaks and seamounts (Genin, 2004), as well as fish and cetacean populations. These aggregations are produced by different mechanisms, some of which might be closely related with the dynamics of the flow-topography interaction.

For mesoscale motions, where the Earth’s rotation effects are important, a relevant mechanism producing vertical displacements is the stretching and squeezing effects on fluid columns as they impinge over variable bottom topography. Laboratory experiments of these processes have been focused on the horizontal behaviour of the flow by using quasi 2D models (see e.g. van Heijst and Clercx, 2009), where horizontal divergence is usually included in 2D formulations. This project, in contrast, is focused on determining the structure of vertical motions produced when a barotropic flow experiences the bottom topography in two basic configurations: a pronounced escarpment and a submerged mountain. Certainly, flows in nature (ocean and atmosphere) are affected by density stratification and this might be an important additional effect to take into account when considering vertical motions. Given its own complexities, however, it might be better to restrict ourselves to the homogeneous case, and avoid for the moment the additional difficulties inherent to experiments with stratified fluids. Click here for further information about this project on the CNRS website.

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