INFRASTRUCTURE FOR ATMOSPHERIC AND OCEANIC PHYSICAL MODELING

The 'Coriolis platform' in Grenoble, as well as the 'Stratified flume' in Toulouse are jointly open to research team from eligible states in the frame of the Integrated Infrastructure Initiative HYDRALAB III funded by the 6th EC framewoork programme. In order to use one of these installations, submit a proposal including the scientific aims of the study, the relevance of using the installation and a brief description of the proposed experiments. A preliminary informal contact with the infrastructure manager is strongly advised before finalizing the proposal. 

Proposals are selected every year by a User Selection Panel. The next deadline is September 30th 2007 and the outcome of the selection is expected by mid April. The same selection panel will also examine access to the ''Coriolis turntable' in Trondheim.

A project typically involves a short preliminary visit to set the details, one month of experiments, and a few months of data processing. A sufficiently strong team (two or three researchers or graduate students) is needed to handle the experiments while processing data in real time. Previous background in laboratory techniques is not a prerequisit as technical support and training is provided (for students or senior researchers), in conformity with the objectives of the EC programme.

Travel and living expenses of the visitors are fully covered by the EC grant, as well as all the expenses related to the realisation of the experiments.

Download the application form

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1-The infrastructure:

The infrastructure comprises two installations, the “Coriolis platform” in Grenoble, and the “stratified flume” of Météo-France in Toulouse. The “Coriolis platform” benefits from a long experience of European access, since 1992, in close contact with oceanography. The “stratified flume” allows one to study a similar physics in a complementary configuration, and opens new fields of application in the atmospheric sciences. We therefore associate these two installations for the EC Access programme, under the joint authority of the “Centre National de la Recherche Scientifique”.

The large size of both installations provides a good dynamical similarity with oceanic and atmospheric flows. Viscous and diffusive effects are indeed very weak, allowing the development of multi-scale turbulent effects and intense fronts, like in natural media. Diffusion of salt is so slow that the vertical stratification can persist during several weeks.

a. The Coriolis platform (Grenoble):

The « Coriolis » rotating platform, 14 m in diameter, is the largest turntable in the world. Its total weight is 150 tons and it supports an extra load of 180 tons. The axis of rotation is vertical with an accuracy ± 3 10^-6 rad. Its rotation period can be set with high stability (dT/T = 10^-4) between 30 and 1000 s and can be modulated by computer control in order to generate permanent or oscillating circular flows, so to simulate tidal effects for instance.

The platform is equipped with a tank of 13 m diameter and 1.2 m height. It can be filled with homogeneous or density stratified water with any vertical profile (e.g. multilayer or linear). The stratification is made by filling the tank through the bottom with increasingly salty water, obtained by computer controlled mixing from two underground tanks with specified salinity and temperature (within 1C). Various fixed or moving obstacles can be installed in the tank (transverse channel 10 m long and 4 m wide, annular shelf, oscillating plates, towed cylinder, cylindrical plunger …). All the instruments, including lasers and computers, stay on the platform, where electricity, water and computer network are available, like in an ordinary laboratory. Researchers can stay on the platform during rotation. Many operations are then easier than in a small rotating tank.

Thanks to the large dimensions, large Reynolds number (inertia/viscous friction) can be reached, and Rossby numbers (inertia/rotation) as low as 10^-3 -10^-2, like in natural geophysical or environmental flows. This is obtained with negligible centrifugal effects, e.g. small curvature of isopycnals.

More about the Coriolis platform

b. Stratified flume (Toulouse):

The large multilayer stratified flume is 22 m long, 3 m wide and 1.6 m deep. The three layers can be separately controlled in thickness, speed and density. In each of the three recirculating layers, the density is maintained by continuous removal and addition of water and brines from two 100m3 reservoirs. The velocity in each layer is adjustable from 3 to 60 cm/s.

The flume can also be used as a towing tank, filled with either homogeneous or density-stratified water, using mixtures of water and brines like in the Coriolis platform. The towing carriage can support large and heavy obstacles as well as all necessary instrumentation and can reach maximum speeds of 50 cm/s.

A three-axis positioning system is available on the carriage, as well as several linear displacement systems for profiling and other applications. The temperature of the air in the laboratory is maintained constant, within ± 0.2 °C at 20 °C. Models with complex topography and specific devices (mechanical and/or electrical) can also be constructed.

More about the Stratified Flume in Toulouse

c. Instrumentation:

Both facilities are equipped with continuous Argon laser (22 W in Toulouse and 8 W in Grenoble) and Yag solid laser, and use highly transparent water for illumination along a large scale laser sheet. Particle Imaging Velocimetry (PIV) systems provide time resolved velocity fields in both horizontal and vertical planes of up to 3 m x 4 m in size, with a relative precision 2%. The laser sheet position is scanned by a computer controlled system, so that image correlation for PIV can be made in a volume. Both vorticity and divergence fields can be computed from the PIV data and directly compared with numerical computations.

Various techniques of flow visualization are available, with dye, hydrogen bubbles or tin oxyde electrolytically released from a wire. Illumination devices and high quality video cameras are available. Tracking of float motion by image processing is available to record lagrangian trajectories in a plane.

A wide variety of local probes is also available, including ultrasonic and laser Doppler velocimeters, salinity and temperature sensors.

Probe displacements and data acquisition are controlled by computer. Tools for data processing and analyses are available.

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2-Eligibility for access :

In the frame of the EC programme, access to the infrastructure is open to research teams of which the majority of researchers, and the team leader, is conducting their research in an Eligible State, not being the country where the Infrastructure is situated (outside France). The term "research team" means a group of one or more researchers preferably not all coming from the same country. Researchers from third countries and from the country where the Infrastructure is situated may participate in a project as part of research team satisfying the rules of eligibility, but without financial support for travel.

Eligible states: European Community and Associated States
Belgium B
Czech Republic CZ
Cyprus CY
Denmark DK
Estonia EE
Germany D
Greece EL
Hungary HU
Spain E
France F
Ireland IRL
Italy I
Latvia LV
Lithuania LT
Luxembourg L
Malta MT
Netherlands NL
Austria A
Poland PL
Portugal P
Finland FIN
Slovakia SK
Slovenia SI
Sweden S
United Kingdom UK
Bulgaria BG
Iceland IS
Israel IL
Liechtenstein LI
Norway NO
Romania RO
Switzerland CH
Turkey TK

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Projects from eligible research teams are selected by an independent selection panel on the basis of their scientific merit and technical feasability. Additional criteria are introduced to encourage the participation of first users, female researchers, and transnational research teams.

To prepare the project proposal, download the application form. Before finalizing the formal project, please contact the infrastructure manager to get advice.

More about the Access Rules and Procedures(Hydralab)

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The experts belong to two lists common to Hydralab. The first list contains experts from one of the Hydralab infrastructures and the second list contains independent experts. At each session, a selection of five to eight experts will be present, a majority coming from the list of independent experts. The independent experts for a particular session will be chosen in such a way as to insure that they have no involvement whatsoever with any of the proposals to be reviewed.

A selection panel specific to 'Geophysical Fluid Dynamics' will meet on May 9th 2006. This covers access to the facilities in Grenoble and Toulouse, as well as to the Coriolis platform in Trondheim. The outcome will be comunicafor mid-May. The composition of this panel is the following:

Andree G., Sweden, hydraulics, waves
Chomaz J.M., France, fluid dynamics, instabilities, stratified fluids
Davies P., UK hydraulics, environmental flows
Etling D., Germany, atmospheric boundary layer
Kaese R., Germany, ocean dynamics

Experts from Hydralab infrastructures:
Ellingsen I.(Trondheim)/Mc Climans T.(Trondheim)
Sommeria J.(Grenoble).

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5-Access conditions and support for users

a-Description of the user's access :
Once a user team has been selected by the User Selection Panel, the team leader and co-workers are encouraged to come to visit the installation during one or two days to set the details of the experiments. This preliminary visit proves to be extremely useful since it is often the first opportunity for the visitors to actually see the installation and better realize its possibilities and constraints. The meeting involves the engineers of the installation and a local contact scientist, who provides advice during the project, and serves as a mediator between the visiting scientists and the technical team. In many projects, scientific collaboration is pursued beyond this minimum help, resulting in common publications.

During the preparatory meeting, a detailed description of the project is written, with sketches and a time table of experimental runs. The appropriate specific equipment is then designed by the engineers and the needed supplies are ordered. The experiments are scheduled according to the requirements of the visitors and to the other experiments planned either by the permanent staff or by other visitors. On the “Coriolis turntable”, a project typically requires one week for installing and testing the set-up, and two to six five weeks of experiments (five weeks total in average). For the stratified flume, we forecast slightly longer projects, six weeks in average.

Visitors are asked to be present during this installation, as it is often an opportunity to finalize the experimental plans. Modifications are sometimes needed to account for unexpected difficulties or evolving ideas. Visitors also use the installation period to learn about the instrumentation and the data processing system. At least one group member is asked to stay during the whole period of installation and experiments, for good coordination. At least two visitors are requested to be present at any time during the experiments, so that the data can be processed and checked before running a new experiment. Additional collaborators can come for shorter periods.

During the whole duration of access, the visitors have full control of the installation, which supports only one experiment at a time. They get office space with telephone and computer facilities. During the regular working hours, at least one of the engineers is permanently available to assist the visitors in their experiments. Local scientists and PhD students also help them to optimize their measurements and data processing. In Grenoble, the visitors can come at any time to analyze their data, although the experiments on the installation itself are generally limited to the regular working days for safety reasons. In Toulouse, access outside the regular working time is possible upon special request.

After their experiments in Grenoble, the visitors have free access to the computer network and software, so they can process their data on-line from their home institution. The raw data and results of each group are kept on hard disks (typically a few hundred Gbytes for a visitor group). Data from Toulouse may be also stored in Grenoble, since on-line access to the computer system of Météo-France is restricted for safety reasons. In all cases, archive back-up are kept on magnetic tapes or other dedicated storage systems, and a copy is given to the visitors, who have also the possibility to come again for further processing and discussion of their results.

b-Reporting and publications:

At the end of the project, the visiting team must provide a written report, conforming with rules specified by the European Commission, (1 page summary report and description of highlights of results). These reports will be submitted by the Infrastructure to the Commission as annual or final reports.

Another short report, including a few illustrative sketches and figures, will be prepare for display on the web site of the infrastructure and Hydralab.

A data report or descriptive report, including experimental set-up, programme of experiments, and detailed explanation of data storage, must be submitted to the Infrastructure. The instrumentation system is computerized and documented to assist the users in this task. The raw data will be made openly accessible in a web server, after a delay of two years after the end of the experiments, during which exclusive access to the data is reserved to the user team.

Finally the users are strongly encouraged to publish their results in conferences and international journals. Users must acknowledge in their publications that their work was supported by the ‘FP6: Structuring the European Research Area’-programme of the EC.

b-Technical and scientific support:

Access to the installations is provided free of charge to the users and includes all infrastructural, logistical, technical and scientific support (including training) that is normally provided to external users of the installations. Travel and subsistence expenses of all users within an eligible team, irrespective of their nationality, will be reimbursed according to the normal internal rules and procedures of CNRS. This covers international travel from the user's institution to the Infrastructure for each period of occupancy of the installation or for a meeting, and a fixed daily subsistence rate for each day of occupancy of the installation (including weekends and public holidays).

In Toulouse rooms are available on site in student housing, and in Grenoble a university organization provides help for booking accommodation. Their life in the city is made as pleasant as possible. Visitors have access to the restaurant of the personal, which favors exchanges with the local team.

A staff of engineers and technicians is working full time on each installation, so they have an outstanding experience of its capabilities. They are familiar with all the measuring techniques and their implementation constraints. The engineers are always fully involved in the design of the experiments; they are responsible for the installation of the measurement equipment and the actual setting up of the experiment. At least one of them is permanently available to assist the visitors during the regular working time. Since each installation can support only one experiment at a time, much attention can be provided to the visitors, helping to make their experiments successful.

The different techniques are taught to the visitors, including image-processing and PIV. Processing programs developed by the local team are now available as free software. The visitors can download it in their home institution. The contact scientist, but also PhD students and/or postdoctoral researchers working directly on each installation, provides wide scientific expertise in fluid dynamics and experimental techniques.

During their stay, the visitors get office space with computer and communication facilities (telephone, fax, mail), like local scientists. In Grenoble, they receive the key of the laboratory, allowing them to come at any time to analyze their data. In Toulouse, they can get authorization for extended time for office access. They can use the library of the laboratory and get on-line access to most scientific journals. They are often invited to give a seminar about their own research.

Both installations are located in large and active research laboratories in fluid mechanics, oceanographic modeling or meteorology, providing a very stimulating scientific environment, with an active flux of foreign visitors. The Centre National de Recherches Météorologiques in Toulouse is a pole of excellence in the world meteorological research community, especially in numerical simulations. The access (under conditions) to the supercomputer Fujistu VPP of Météo-France provides opportunities of coupling numerical modeling with experimental projects.

More about the Access Rules and Procedures(Hydralab)

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List of user group leaders

Institution

(country)

Ref. #

(year)

Access provided

(operating days)

Topic

Dr. Angelo Rubino

30

Frictional and nonfrictional decay of surface frontal anticyclonic vortices in a stratified environment

Summary

Dr. Peter J. Thomas

25

Experiments on Gravity-Driven Surface Currents Simulating Fresh-Water River Discharges into the Ocean

Summary

Prof. Dieter Etling

30

The effect of boundary turbulence on oscillating flows in the vicinity of submarine canyons

Summary Report(.pdf)

Netherland Institute for Sea Reasearch, PO Box 59, 1790 AB Texel, Nederland

15

Non-axisymmetric inertial wave propagation, focusing and mean flow generation

Summary Report(.pdf)

30

Mean flow generation/modification in beta-plane geostrophic turbulence

Summary Report(.pdf) (.html)

Dept. of General Physics, University of Torino, Via Pietro Giuria 1, 10125 Torino, Italy

24

Governing parameters for the equation of turbulent diffusion in the planetary boundary layer of a rotating flow

Summary Report(.pdf)

James Rennell Division, Southampton Oceanography Center, EmpressDock, Southampton SO14 3ZH, UK

25

Rotating exchange flows through straits with multiple channels

Summary Report(.pdf)

Dept. Computer Science,Technion, Haifa 32000, Israel

13

The effect of rotation on axisymmetric gravity currents with stratified fluids and inclined bottom

Summary Report(.pdf)

12 April-18 May

2003

30

Rotating stratified flow over rough topography

Summary

The effect of rotation on axisymmetric gravity currents with stratified fluids and inclined bottom.
Summary

RESULTING PUBLICATIONS

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List of user group leaders

Institution

(country)

Ref. #

(year)

Access provided

(operating days)

Topic

D. Etling

IfMK

Univ. Hannover (D)

1

(1996)

44

Laboratory experiments of ocean outflow

S. Pierini

Inst. Meteo. Oceanogr.

Univ. Napoli (I)

2

(1997)

25

Laboratory modeling of topographic Rossby modes

K. Börenas

Dept Oceanography,

Univ. Göteborg (S)

3

(1997)

28

Eddy formation on the downstream side of a sill

L. Maas

NIOZ

(NL)

4

(1998)

10

Inertial waves attractors (test exp.)

DAMPT

Univ. Cambridge (UK)

5

(1999)

20

Rotation’ effects on axisymmetric particle-driven flows

NIOZ

(NL)

6

(1999)

30

Inertial waves attractors

Univ. Dundee (UK)

IfM Kiel (D)

7

(1999)

35

Model experiments on meddy-seamount interaction

A. Provenzale

CNR- Fiume (I)

Univ. Torino (I)

8

(1999)

30

Transport of passive tracers by coherent vortices

D. Dritschel

Univ. Warwick (UK)

9

(2000)

25

Breakdown of columnar vortices in a rotating stratified fluid at finite Ro, Fr and Re numbers

TOTAL

247

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