Changes between Version 1 and Version 2 of WikiStart

Sep 6, 2017, 3:21:09 PM (3 years ago)



  • WikiStart

    v1 v2  
    1 = Welcome to Trac 0.11.7 =
    3 Trac is a '''minimalistic''' approach to '''web-based''' management of
    4 '''software projects'''. Its goal is to simplify effective tracking and handling of software issues, enhancements and overall progress.
    6 All aspects of Trac have been designed with the single goal to
    7 '''help developers write great software''' while '''staying out of the way'''
    8 and imposing as little as possible on a team's established process and
    9 culture.
    11 As all Wiki pages, this page is editable, this means that you can
    12 modify the contents of this page simply by using your
    13 web-browser. Simply click on the "Edit this page" link at the bottom
    14 of the page. WikiFormatting will give you a detailed description of
    15 available Wiki formatting commands.
    17 "[wiki:TracAdmin trac-admin] ''yourenvdir'' initenv" created
    18 a new Trac environment, containing a default set of wiki pages and some sample
    19 data. This newly created environment also contains
    20 [wiki:TracGuide documentation] to help you get started with your project.
    22 You can use [wiki:TracAdmin trac-admin] to configure
    23 [ Trac] to better fit your project, especially in
    24 regard to ''components'', ''versions'' and ''milestones''.
    27 TracGuide is a good place to start.
    29 Enjoy! [[BR]]
    30 ''The Trac Team''
    32 == Starting Points ==
    34  * TracGuide --  Built-in Documentation
    35  * [ The Trac project] -- Trac Open Source Project
    36  * [ Trac FAQ] -- Frequently Asked Questions
    37  * TracSupport --  Trac Support
    39 For a complete list of local wiki pages, see TitleIndex.
     3= '''SLOCET''' =
     5||Project (long title)||Shelf sLOpe impact on Coastal Eddy Turbulence||
     6||Campaign Title (name data folder)||17SLOCET||
     7||Lead Author||Alex Stegner||
     8||Contributors||Remi Laxenaire, Ted Johnson, Chunxin Yuan,  Joel Sommeria, Samuel Viboud||
     9||Date Campaign Start||13/02/2017||
     10||Date Campaign End||10/03/2017||
     12= 0 - Publications, reports from the project =
     13= 1 - Objectives =
     14New theoretical analyses and numerical computations have shown that regions of the continental shelf where the offshore shelf profile changes significantly can be sources of coastal eddies and thus regions of coastal turbulence. The size and intensity of the eddies is determined by the rapidity of the change in the profile and also by the stratification of the flow on the shelf. Eddies can be excited both by coastal currents (Pennel et al. 2012; Cimoli et al. 2017) passing along the shelf over the profile change and, in the correct parameter regime, by incident Topographic Rossby Waves (Rodney & Johnson 2014). A series of experiments will be carried out using PIV in both layers to demonstrate this mechanism for coastal eddy generation in two­ layer flow. The results will be compared with existing and new theory and with new numerical simulations run with the MITgcm.
     16= 2 - Experimental setup: =
     17== 2.1 General description ==
     18In order to mimic the oceanic stratification a two ­layer salt stratification with a thin upper layer ( H1= 8cm) above a deep layer ( H2=72cm) is set up on the rotating platform.The ration period is fixed at To=50s (i.e. a Coriolis parameter f=4*pi/T0=0.25s-1) and adjusting the density difference rho2-rho1=10 g/l between the two layers give baroclinic deformation radius Rd around 32cm. This deformation radius will be large in comparison with the upper layer thickness ( Rd>H1) but remain small in comparison with the tank diameter D=13m. Hence, for eddies in the upper layer, we will satisfy the shallow­ water aspect ratio (H1/Reddy<<1) at meso­scale when the typical radius is of the same size or larger than Rd.
     20== 2.2 Wave maker ==
     21== 2.3 Jet forcing ==
     22== 2.4 References axis along the wall (horizontal and vertical) ==
     23By definition we will use Ox and Oy axis to define the along shore and the cross shore axis. The central reference point (0,0) along the wall is chosen to be the closest point to the center of the tank (also labeled '''M0'''). Positive direction corresponds to the mean wave or the mean flow direction. We use seven references points along the wall to quantify the impact of the free surface deformation and the possible vertical deviation of the laser sheet.
     25[[Image( )]]
     27All these points will be measured every day before starting the experiment.
     30||H_coast (cm)||||||||||||
     31||H_laser_up (cm)||||||||||||
     32||H_laser_down (cm)||||||||||||
     34== 2.5 Fixed Parameters ==
     36||$T_0$||Rotation period||$50 \ s^-^1$||||
     37||$\Delta\rho$||Density difference||$10 \ kg \ m^-^3$||The vertical stratification evolves in time, here we consider the maximum and minimum densities||
     38||$W$||Upstream shelf width||$1 \ m$||||
     39||$S$||Upstream shelf slope||$60%$||||
     40||$\nu$||Viscosity||$10^-^6m^2s^-^1$ ^||||
     41||$L$||Total length of the wall||$11 \ m$||||
     43== 2.5 Variable Parameters ==
     44||'''Notation'''||'''Definition'''||'''Unit'''||'''Initial Estimated Values'''||'''Remarks'''||
     45||$Htot$||Total water depth||$cm$||80||estimated at the center of the wall||
     46||$Hcoast$||Water depth at coast (at M0)||$cm$||20||estimated at the center of the wall||
     47||$W_1$||Downstream shelf width||$m$||0-1-4||||
     48||$S_1$||Downstream shelf slope||$%$||0-15-60||||
     49||$T_{flap}$||Flap period||$s$||40-200||||
     50||$A_{flap}$||Amplitude of carriage motion||$cm$||10-60||peak to peak amplitude||
     51||$V_{flap}$||Max speed of oscillating carriage||$cm/s$||1-4||||
     52||$Q_{jet}$||Flow rate of the jet||$l/min$||0.5-4||||
     54== 2.6 Additional Parameters ==
     55||'''Notation'''||'''Definition'''||'''Unit'''||'''Initial Estimated Values'''||
     56||$g'$||Reduced gravity||$cm/s2$||9.81||
     57||$Rd$||Baroclinic deformation radius||$cm$||32.4||
     58||$RD$||Barotropic deformation radius||$cm$||1050||
     59||$H2$||Mean lower layer depth over shelf||$cm$||46||
     61== 2.7 Definition of the relevant non-dimensional numbers ==
     62Vertical aspect ratio (gamma), $\ gamma = H1/H2$.
     64Froud number (equivalent Fd), $Fd = Umax/fRd = Umax/C$.
     66where C is the maximum phase speed of internal gravity waves $C=sqrt(g'H1)$
     68Wave Froude number $Fdwave = Umax/VTRW$
     70where VTRW is the maximum phase speed of Topographic Rossby Wave $VTRW=???$
     72= 3 - Instrumentation and data acquisition =
     73== 3.1 Instruments ==
     74'''Density profiler (DP)'''
     76'''Particle Imaging Velocimetry (PIV)''' A Spectra-Physics Millennia ProS 6W YAG continuous laser (532 nm) in conjunction with 3 cameras was used to provide PIV images. The laser light sheet was brought in parallel to the floor of the channel. The light sheet can then be racked in the vertical through a series of steps through the use of a motorized traverse (tilted at 3.5 degrees to match the slope of the channel) and a mirror set at 45 degrees. The laser has another set of optics to point the light sheet down at the mirror, producing the light sheet. There is a glass window that enables the laser beam to go through the surface of the water tank. A 3D animation of the laser is in the ‘videos’ subfolder of the Photos folder. The laser light sheet positions are then synchronized with the PIV cameras. The field of view extends from close to the upstream end of the first bend, towards the mid-point of the second bend.
     78Later experiments used larger seeding particles, 200 micron polystyrene particles for the flow seeding. These work very well for these situations where the measurement area is larger than 2 square metres. The three PIV cameras consist of one Falcon1 camera (Falcon 4M, CMOS 2432*1728 pixels, 10 bits) over the upstream part – with a 35 mm objective lens, PCO2 over the first bend with a 35 mm objective lens, and PCO3 over the most downstream part of the PIV measurement area, which has a 20 mm objective lens. 15 slices in the vertical are taken, each containing 20 images and these are repeated 10 times. Four different times between frames are used, since the velocities were not known a priori and vary as a function of height in the gravity current. So as such, no specific frame rate is used. All this is in the .xml files which can be read by a text editor. The two PCO cameras are PCO.edge5.5 CMOS cameras (2560*2160 pixels). The general approach is to have the lowest slice at approximately 2 cm above the floor, and then there are 2.5 cm heights between each successive level. These varied over time however, so there are a number of slightly different setups – see below. The sequence starts at the highest point, and then steps down through the flow, to the bottom, before switching back to the top again. Heights of laser slices (22/09/16 – 2.5 cm but after that 12/10/2016 and 14/10/2016 and 19/10/2016 all at basal 2 cm).
     80== 3.2 Definition of time origin and instrument synchronisation ==
     81This section relates to the main experiments, and not the test experiments (see diary entries for details of earlier experiments). Conductivity as measured in the inlet box (Probe C1) is seen to vary initially due to mixing within the input box, and because a higher input rate is used in the first minute of the experiment (~11-13 L/s in the main experiments – see Section 6) than later in the flow (~6 L/s). This initial pulse is intended to help to clear fluid out of the inlet box. The time origin is judged to be that point at which the value of this conductivity probe (C1) becomes approximately constant. The timings and synchronisation of the ADV, UVP and the Siphons are controlled with the aid of a stopwatch which is started at the time origin. PIV is then initiated soon after the time origin (approximately 0 minutes) to approximately 10 minutes run time. The timing of PIV initiation can be determined retrospectively, relative to the time origin, because the traverse initiation (that runs the ADV) is specifically linked to the time origin (ADV measurements start at 15 minutes and runs to 35 minutes), and both the traverse and the PIV are tied into the main control software. Thus knowing the time difference between the traverse initiation and the PIV initiation, and subtracting this from 15 minutes provides the PIV initiation relative to the time origin. The UVP and Siphon data are independent as their outputs are not directly tied into the Coriolis control software in the same way that the traverse is. Siphons are initiated after 5 minutes, and the cross-stream UVPs are started at 5 minutes (run until 15 minutes), whilst the downstream UVPs are started at 25 minutes are run until 35 minutes. For 19/10 and 20/10 files the start of the PIV integrates directly with the time origin, all other aspects as before. For PIV analysis, the time origin of the experiment is worked out from the C1 conductivity probe in the input box, where it exhibits the initial sharp rise (near instantaneous) as the flow input starts.
     83== 3.3 Requested final output and statistics ==
     84Batch processed camera data in to .png files for those experiments from 18-43 that have PIV data, so that images are in a non-proprietary format. PIV analysis of the flow field through multiple horizontal slices in different Z-positions, for the non-rotating case, and for the rotating cases (experiments 18-43 as above), dependent on the quality of the captured PIV images. Average velocity vectors for the channel slices. Potentially information on vorticity would enable the smaller-scale vortical structures that are obvious in some of the videos, to be identified.
     86= 4 - Methods of calibration and data processing =
     87The MSCTI conductivity probe is calibrated after each set of experiments when the tank is drained (see Section 3.1 for full details). The ADVs have 4 heads and as such this enables some internal verification of the instrument. The ADV and UVP datasets are processed using a series of bespoke Matlab scripts. The PIV data will be processed using a bespoke script. Access to commercial PIV processing packages is also available.
     89The images for PIV are calibrated from images of grid put in 0_REF_FILES/Calib_absolu. The 3D calibration involves 'intrinsic parameters' of the optical system obtained from images of the same grid seen with tilt angle (put in /Calib-14-09-3D). Then rotations and translations of the calibration points are introduced to adjust the relationship between image coordinates and physical coordinates defined in section 2.2. See for details of the method. The calibration parameters are copied in a xml file beside each image folder with the same name (for instance PCO2.xml for PCO2/). The xml files also containing all the timing information.
     91All the images and processing results from the images are in the folder 0_PIV under the folder with the name of the experiment.
     93The images are first extracted from their initial format and written as .png images (compression with no loss of data) labelled by two indices i and j=1 to 20. The index i generally runs from 1 to 150 scanning 15 levels (then coming back to each level 1O times).
     95A first step in image processing after extraction is to subtract the fixed background and rescale the image intensity leading to a image folder with extension .sback. PIV results are stored as netcdf files (extension .nc) in a folder .sback.civ. These data are still in pixel displacement.
     97Final velocity data in phys coordinates are stored as 2D matrices under the netcdf format in folders with extension .sback.civ.mproj. They are defined on a physical grid with 1 cm mesh.
     99= 5 - Organization of data files =
     100All data related to the project are in: \\SERVAUTH4\share\project\coriolis\2016 or \\\share\project\coriolis\2016
     102 * 0_DOC: miscellaneous documentation and reports
     103 * 0_MATLAB_FCT: specific matlab functions
     104 * 0_PHOTOS: photos of set-up
     105 * 0_PIV
     106   * Each ‘PIV’ folder contains subfolders for each of the 3 PIV cameras: Dalsa (sometimes Falcon1 – it’s the same thing); PCO2; PCO3 [these are named after the different brands of camera]. Other folders include PCO2.png and PCO3.png which contain processes images of the PCO cameras that are in a non-bespoke format. Other folders that can be within the Camera folder include: Dalsa.sback; Dalsa.sback_1; PCO2.png.civ; PCO2.png.civ_1; PCO2.png.civ_2; PCO2.png.sback: PCO2.png.sback_1; PCO3.png.sback_1. .sback files refer to those files where the background has been subtracted, then civ_1 contains images with the first PIV iteration as processed in UVMAT (Joel’s code) and shows the raw data – with or without the rejected vectors; vectors are shown in four colours, blue = best, green = medium, red = poor, and pink = false. A box can be clicked to hide the false vectors. Civ_2 uses a spline interpretation to interpolate between vectors, so long as they are close enough to the surrounding vectors. Then interpolates all the vectors onto a regular grid. Times for the .png images are in the XML files, or netcdf files.
     108 * 0_Processing: UVP processing scripts in Matlab
     109 * 0_REF_FILES: files of general use (calibration data, grids ...)
     110 * EXP1, EXP2, folder for each experiment with names given in the table below. The names refer to ‘fix’ for non-rotating fixed case, ‘rot’ for rotating case, ‘str1’ for the first straight position (also called position X1), and ‘apex 2’ , for the apex in bend 2 (also referred to as position X4).
     111   * Within each experiments, there is a folder with PIV imagery called ‘Camera’, one for ADV data – ‘ADV’, one for UVP data – ‘UVP’, and one for the data coming directly off of the Coriolis table control system ‘LABVIEW’. Some experiments also contain an ‘Images’ folder or a ‘Gopro folder’ containing Gopro videos.
     112     * Each ‘Camera’ subfolder contains subfolders for each of the 3 PIV cameras: Dalsa (sometimes Falcon1 – it’s the same thing); PCO2; PCO3 [these are named after the different brands of camera]. Other folders include PCO2.png and PCO3.png which contain processes images of the PCO cameras, that are in a non-bespoke format. Other folders that can be within the Camera folder include: Dalsa.sback; Dalsa.sback_1; PCO2.png.civ; PCO2.png.civ_1; PCO2.png.civ_2; PCO2.png.sback: PCO2.png.sback_1; PCO3.png.sback_1
     113     * Each ‘ADV’ subfolder, contains two sub-folders: ‘nkt_files’ containing raw Nortek files, and the ‘mat_files’ are the exported raw data in Matlab format.
     114     * Each ‘UVP’ subfolder contains two folders – one with the experiment name (which is the downstream velocity data) recorded downstream of the velocity inflection downstream of bend apex 2, and one with experiment name ‘_cross’ which contains the cross-stream UVP data recorded at bend apex ‘2. These two folders contain text files for each of the probes. The convention is that Probe 1 is the basal probe, with each subsequent probe being successively higher. There are also .mfprof files which are the raw UVP data in native format. All probes are also integrated into single Matlab files. Lastly, there is a Logfile with the header file for the UVP detailing all of the parameters used in the run.
     115     * Each ‘LABVIEW’ subfolder contains: 1) a .lvm file which is a text file and contains a time-stamp, two voltages for the Conductivity probe on the traverse (C0 – Conductivity, and T0 – temperature [this latter one doesn’t work]), a Trig_cam heading representing the Trigger for the PIV Cameras, Conductivity probe in the input box (C1 and T1), and C2 (this was conductivity for a second probe in the input box which was briefly used before breaking. There is always a record for this but it is just background noise. 2) _position.lvm file which is an XYZ file with a times for the movement of the traverse. 3)Some folders also contain files. These are netcdf files and contain the vector data from the processed PIV images.
     117= 6 - Table of Experiments: =
     118||'''Exp No.'''||'''Name'''||'''Date_begin'''||'''Hcoast'''||'''W1'''||'''S1'''||'''Angle_flap'''||'''T_flap'''||'''A_flap'''||'''Vmax_flap'''||'''Q_jet'''||'''d_jet'''||'''dt_forcing'''||'''delay'''||'''dt_record'''||'''Cameras'''||
     120||'''Test Exp'''||||||||||
     121||1||EXP01||??????||17.7||1||60||90||200||60||0.9||-||-||2000 / 34||0||9856.5||PCO||
     122||2||EXP02||??????||17.7||1||60||90||100||60||1.9||-||-||3000 / 50||100||3250||PCO||
     123||3||EXP03||??????||17.7||1||60||90||100||30||0.9||-||-||3000 / 50||50||3250||PCO||
     124||4||EXP04||??????||17.7||1||60||90||60||60||3.1||-||-||1800 / 30||50||1850||PCO||
     125||5||EXP05||??????||17.6||1||60||90||40||38||3.0||-||-||1200 / 20||50||1500||PCO||
     126||6||EXP06||??????||17.6||1||60||90||80||75||3.0||-||-||2400 / 40||50||2770||PCO||
     127||7||EXP07||??????||17.6||1||60||90||20||20||3.1||-||-||2400 / 40||50||750||PCO||
     130||10||EXP10||??????||17.6||1||-||-||-||-||-||35.3 to 60||60||2965.5/49||0||2965.5||PCO||
     133||'''Exp Canyon'''||||||||||
     134||11||EXP11||22/02 11:41||18||0||0||90||60||16||0.8||-||-||3000/50||50||3300||PCO/FALCON/Lumenera||
     135||12||EXP12||22/02 15:33||18||0||0||90||60||22||1.2||-||-||3000/50||300||3300||PCO/FALCON/Lumenera||
     136||13||EXP13||22/02 17:09||18||0||0||90||60||36||1.9||-||-||3000/50||300||3300||PCO/FALCON/Lumenera||
     137||14||EXP14||22/02 18:58||18||0||0||90||60||46||2.4||-||-||3000/50||300||3300||PCO/FALCON/Lumenera||
     138||15||EXP15||23/02 10:11||18||0||0||90||60||12||0.6||-||-||3000/50||300||3300||PCO/FALCON/Lumenera||
     139||16||EXP16||23/02 12:52||18||0||0||90||60||18||0.9||-||-||3000/50||300||3300||PCO/FALCON/Lumenera||
     140||17||EXP17||23/02 16:25||18||0||0||90||80||30||1.2||-||-||4000/67||800||4800||PCO/FALCON/Lumenera||
     141||18||EXP18||24/02 09:20||18||0||0||57.5||80||34||1.3||-||-||3517/59||400||3917||PCO/FALCON/Lumenera||
     142||19||EXP19||24/02 11:27||18||0||0||57.5||60||16||0.9||-||-||2220/37||780||3000||PCO/FALCON/Lumenera||
     143||20||EXP20||24/02 13:21||18||0||0||57.5||45||50||3.5||-||-||1800/30||450||2250||PCO/FALCON/Lumenera||
     144||21||EXP21||24/02 14:56||18||0||0||57.5||80||32||1.3||-||-||3200/53||800||3600||PCO/FALCON/Lumenera||
     145||22||EXP22||27/02 14:39||18||0||0||90||60||16||0.8||-||-||2400/49||600||3000||PCO/FALCON/Lumenera||
     146||23||EXP23||27/02 16:09||18||0||0||90||60||46||2.4||-||-||2400/49||600||3000||PCO/FALCON/Lumenera||
     147||24||EXP24||01/03 10:42||18||0||0||-||-||-||-||120||30||???||0||???||PCO/FALCON/Lumenera||
     148||25||EXP25||01/03 11:17||18||0||0||-||-||-||-||80||30||???||0||???||PCO/FALCON/Lumenera||
     149||26||EXP26||01/03 15:57||18||0||0||-||-||-||-||55.8||60||???||0||???||PCO/FALCON/Lumenera||
     150||27||EXP27||02/03 09:00||18||0||0||-||-||-||-||24||60||???||0||???||PCO/FALCON/Lumenera||
     151||28||EXP28||02/03 11:15||18||0||0||-||-||-||-||25.3||60||???||0||???||PCO/FALCON/Lumenera||
     152||29||EXP29||03/03 10:19||18||0||0||-||-||-||-||56||60||???||0||???||PCO/FALCON/Lumenera||
     153||30||EXP30||03/03 11:46||18||0||0||-||-||-||-||85||60||???||0||???||PCO/FALCON/Lumenera||
     154||31||EXP31||03/03 14:42||18||0||0||-||-||-||-||120||60||???||0||???||PCO/FALCON/Lumenera||
     155||32||EXP32||03/03 16:08||18||0||0||-||-||-||-||75||60||???||0||???||PCO/FALCON/Lumenera||
     157||'''Exp Smooth Shelf'''||||||||||
     158||33||EXP33||08/03 14:55||19||0||0||-||-||-||-||37.5||60||???||0||???||PCO/FALCON/Lumenera||
     159||34||EXP34||08/03 16:26||19||0||0||-||-||-||-||69||60||???||0||???||PCO/FALCON/Lumenera||
     160||35||EXP35||08/03 17:56||19||0||0||-||-||-||-||107||60||???||0||???||PCO/FALCON/Lumenera||
     162= 7 - Diary: =
     163'''Wednesday, February 15th 2017'''
     165First day of experiment ! We have many difficulties to get an homogeneous distribution of particles at the level of the laser sheet (located in the dense lower layer). We first spray at the surface the particles (30 microns, 1013 g/l) diluted with quite dense salty water. But after waiting one hour the particles never reach the level of the laser sheet... Hence, in order to be able to visualize something we started to inject directly inside the lower layer with the sprayer. We then succeed to disperse high concentration of particles at the level of the laser sheet.
     167Three test experiments were performed with the oscillatory flap.
     169'''EXP01''': '''Oscillation''' period 200s, very poor repartition of particles and hard to distinguish the global flow structure.
     171||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     173||PCO||after carriage||100ms||0.1||?||?||||
     175Laser parameters
     181'''EXP02''': '''Oscillation''' period 100s, we starts to see some oscillation in the flow that propagates along the wall. A large-scale shear flow seems to establish along the shelf.
     183||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     185||PCO||after carriage||50ms||0.5||?||?||||
     187'''EXP03''': '''Oscillation''' period 100s, reduced oscillation amplitude
     189||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     191||PCO||after carriage||50ms||0.5||?||?||||
     193'''Thursday, February 16th 2017'''
     195The repartition of particles over the tank is better when we arrive in the morning. During all the day, particles are added at the level of the laser beam following the same method than the previous day. The laser angle was changed from 60° to 75 °.   Three interdependent parameters of the carrier can be tuned to set the forcing of the oscillating flat: T_flap, A_flap and Vmax_flap. We choose to set Vmax_flap to 3 cm/s to improve the comparison with the MITgcm simulations.  Four experiments with different amplitudes and periods were performed to study the sensibility of the formation of topographic wave. In these experiments, we do not stop the record of the camera when we stop the flap to record what happen when the forcing is stopped.
     197'''EXP04''': '''Oscillation''' period 60s
     199||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     201||PCO||after carriage||50ms||0.1||?||?||||
     203Laser parameters
     209'''EXP05''': '''Oscillation''' period 40s
     211||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     213||PCO||after carriage||50ms||0.5||?||?||||
     215'''EXP06''': '''Oscillation''' period 80s
     217||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     219||PCO||after carriage||50ms||0.5||?||?||||
     221'''EXP07''': '''Oscillation''' period 20s
     223||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     225||PCO||after carriage||50ms||0.5||?||?||||
     227At the end of the day, we want to perform an experiment with the laser in the upper layer but the upper limit of the laser is inside the layer of transition between the upper and lower layer. Consequently, it changes the angle of the laser due to the refraction of the beam into the inhomogeneous layer. This upper limit is fixed by the position of the mirror on which the laser beam is reflected that need to be moved when the tank is empty.
     229'''Friday, February 17th 2017'''
     231This day is dedicated to the formation of the coastal current in the upper layer.
     233For the moment, the control of the flow rate is complicated. It can be done by tuning the opening of one valve and estimating the flow rate in the tanks above the platform. It is done by looking at the evolution of the water levels at during 1 minute given by a stopwatch. This is not precise and it takes time to reach the flow rate targeted. We have to build and test some diaphragms to reduce the size of the pipe. Each diagram will be associated with a flow rate which will be constant.
     235There is no laser in the upper layer. The particles are directly mixed with the water in the tanks above the platform before their injection in the surface layer. These particles are lighted by the diffusion of the laser from below. Consequently, it is possible to see the water added by the injectors into the upper layer but all the other part of this layer are not visible. Indeed, the signal of the particle at the depth of the laser beam (i.e. in the lower layer) is too strong. This is a main problem that has to be changed by moving up the mirror which reflect the laser.
     237The stratification is not very good when filling from the bottom of the tank. The process will consequently be changed. The tank will firstly be filled with the salty water. The upper layer will be added directly into the surface layer using diffusers.
     239The laser stopped by itself during the experiment 8. This happened also shortly after the beginning of an experiment we did not save as no water injected had not enough time to reach the camera field-of-view. The problem comes from the tarpaulin of the platform which is close to the fan of the laser cooler. This blocks the evacuation of the air and increase the temperature inside the laser device. To prevent any damage, the laser is automatically shut down when a maximum temperature is reached. Now, the tarpaulin is open behind the cooler but it results in a hole letting the air to enter inside the platform. Moreover, the fan of the cooler might warm the water surface locally which can perturb the upper surface. Consequently, the cooler has to be put outside the tarpaulin to prevent all these effects.
     241The exit of the injector is not along the wall as it exists a gap of 20.5 cm. A large amount of the water injected turn to the right when it is injected and do not flow along the wall. This effect reduces when the flow rate is increased. It needs a flow rate by far superior (30 l/min) than what it was planned (7 l/min). Moreover, the separation of the flow due to the geometry adds a lot of perturbation that lead to the creation of large eddies. For example, a large cyclonic eddy stays close to the exit of the injector for a flow rate of 7l/min. We need to prevent this effect adding a wall between the onshore part of the injector and the wall.  This solution was tested with a wooden sheet hold by hand which seems to drastically reduce this effect. A fixed one will be added when the platform will be empty on Monday.
     243All the different problems mentioned before will be solved when the platform will be empty on Monday. Three experiments were performed but, as the flow is perturbed in many ways, we do not think that it will be representative of the flow when the different problems will be solved.
     245'''EXP08''': '''Injection''' flow rate 7.2 l/min
     247||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     249||PCO||after carriage||50ms||0.5||?||?||||
     251'''EXP09''': '''Injection''' flow rate 7.4 l/min
     253||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     255||PCO||after carriage||50ms||0.5||?||?||||
     257'''EXP10''': '''Injection''' flow rate 35.3 l/min to 60 l/min. We increased the flow rate from 35.3 l/min to 60 l/min after XXXX minutes of recording the see its impact on the formation of the coastal current.
     259||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     261||PCO||after carriage||50ms||0.5||?||?||||
     263'''Monday, February 20th 2017'''
     265The platform is empty in the morning.
     267The day begins by the calibration of the two CTD sensors using 7 samples which span from 998.6 to 1025.1 kg/m3. One 2nd order polynomial regression is applied for each of them to define the relation between the voltage measured and the water density. The profiles obtained are presented in the following figure.
     271All the distance between each element of the experimental setup and the point of reference along the wall are measured. A schematic of the setup of the first week called smooth shelf configuration is presented in the following figure.
     275The three downstream plastic sheets were removed to replace them by a triangle which make the transition between the slope and the flat floor. Along the wall, it results in 6.75m of constant shell, 2.74m of transition and 3.27m of flat bottom.
     277The calibration of two of the three fixed cameras is also done using a target of 2mx2m in the field of view of each of them. Firstly, the target is kept horizontal for the first pictures. Then, it is moved in all directions to have a 3D representation of the target that help to correct the picture. This calibration is not done for the camera recording the flap and the injector as we did not succeed to have a clear picture in the computer.
     279We saw last week that a lot of turbulence is created at the exit of the injector. A schematic of what was observed is presented in the following figure.
     283To prevent these perturbations, the shelf is extended and now the exit of the injector is above the shelf to ensure that the water flow directly above it. Secondly, a vertical plastic sheet that link the exit of the injector and the wall is added. We hope that this will prevent the return of the current below the injector and will help the injected water to reach directly the vertical wall.
     285'''Tuesday, February 21th 2017'''
     287The position of the carrier is changed. The flap is now linked to the downstream edge of the carrier to improve the field of view in the cameras upstream of the transition area.
     289The laser length is now changed to 90°. The mirror of the laser is also lifted of 8cm to have the laser sheet in the upper homogeneous layer. The laser device is also rotated to have enough light both over the transition area and over the flat bottom.
     291All the distance between each element of the second experimental are measured. A schematic of the setup of the second week in the canyon configuration is presented in the following figure.
     296||H_coast (cm)||||||18||||||
     297||H_laser_up (cm)||||||||||||
     298||H_laser_down (cm)||||||||||||
     300'''Wednesday, February 22th 2017'''
     303||H_coast (cm)||19.7||19||18||18.5||19||
     304||H_laser_up (cm)||/||/||/||/||/||
     305||H_laser_down (cm)||9.5||3.5||4||7.3||/||
     307A CTD profile recorded this morning can be compared to the one recorded at the end of the day yesterday in the following figure : [[Image(]]
     310||H_coast (cm)||19||18||18.5||18||18.8||
     311||H_laser_up (cm)||/||/||/||/||/||
     312||H_laser_down (cm)||6||2.5||3.5||5||/||
     314Bottom density => 1009.5 (T 20.9) Surface density => 1002 (T 19.9)
     321'''Thursday, February 23th 2017'''
     324||H_coast (cm)||19||18.7||18||18||18.5||
     325||H_laser_up (cm)||/||/||/||/||/||
     326||H_laser_down (cm)||/||6.6||3.4||2.5||/||
     328Changeemnt de sonde aprés EXP15, C0 est déplacé et maintenant devient C2. La nouvelle sonde C0 est à la place de l'ancienne C0. Surface nouvelle C0/TO 371 surface libre. C2 est ajoutée aux données lors de l'expérience 17. Le gain de cette dernière est modifié aprés 5min de cette même expérience.
     335'''Friday, February 24th 2017'''
     337Position of the flap changed in the morning. A schema of the two positions is given in the following figure.
     347'''EXP18''': '''Oscillation'''
     349Problem of data recording with the PCO camera during the experiment 18. First 4'35'' of the record were not stored due to a lack of disk space.''
     351''We stopped the recording before the end of the experiment as the number of particles was not sufficient.''
     353'''EXP19''': '''Oscillation'''
     355'''EXP21''': '''Oscillation'''  period 80s
     357||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     359||PCO/FALCON/Lumenera||before carriage||50ms||0.3||?||?||||
     361[[BR]]'''Monday, February 27th 2017'''
     363The extraction of the surface layer during the weekend did not succeed. 15 cm of water was extracted but there is still a stratification on the profiles.
     365The remaining water is mixed by hand and the 15 last centimetres are added using water with the density of the bottom layer. The final density is 1009.1 g/m!^3 at 20.2°C. The difference of height with two layers stratification is less than 1 mm.
     367Checked the horizontal of the laser sheet.Change the flat position to have its reference perpendicular to the wall.
     369The mixing of the water re-suspend the particles in all the water column. The repartition is now homogeneous but they are in all different layers but not only at the position of the laser sheet. The resulting pictures are less complicated to interpret by eyes because the fronts are less obvious.
     371'''EXP22''': '''Oscillation''' '''__Barotropic__''' period 60s amplitude 16cm
     373||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     375||PCO/FALCON/Lumenera||before carriage||50ms||0.3||?||?||||
     377'''EXP23''': '''Oscillation''' '''__Barotropic__''' period 60s amplitude 46cm
     379||'''Cameras'''||'''location'''||'''exposure'''||'''dt'''||'''size'''||'''avg scale'''||||
     381||PCO/FALCON/Lumenera||before carriage||50ms||0.3||?||?||||
     383The recycling of the water is started at the end of the day.
     385[[BR]]'''Wednesday, March 1st 2017'''
     387Injector, reduction of its surface
     389'''EXP23''': '''Inejctor''' '''diaphragm 19mm "'''
     391'''EXP24''': '''Inejctor''' '''diaphragm 15mm "'''
     393We test the relation between the flow rate $Q[L/min]$ and the diameter of the diaphragm $D[mm]$. The relation gives the following figure.^^
     403'''Thursday, 2 of March  2017'''
     409Dist from surface =>1=>Hcoast=18cm Laser_surf=3.4cm; -1=>LAser_surf=3.2cm, 0=>Hcoast=18cm LAser_surf=5.2cm
     412||H_coast (cm)||||18??||18||18||
     413||H_laser_up (cm)||||14.6||12.8||14.8||||
     414||H_laser_down (cm)||||||||||||
     416Samuel starts the day by calibrating ultrasound probes. He also changed on probe (Acq 3. Third from the wall). Values are stored in the file : calib probe 02/03. He different positions are : 0/-0.5/-1/+1/+0.5/0
     418Profile made this morning is presented in the following figure. [[Image(]]
     420EXP27=> change of the laser position at 09.39.
     422'''Friday, 3 of March 2017'''
     428We lifted the ultrasound sensors of 42mm.
     430EXP29 =>10h19 13 D (FPS 3)
     432Mooving of the sensor closer to the wall
     434EXP30 =>11h46 16 D (FPS 10)
     436EXP31 =>14h42 19 D (FPS 10)
     438EXP32 =>16h08 15 D (FPS 10)
     440'''Wednesday, 8 of March 2017'''
     443||H_coast (cm)||||||19||18||
     444||H_laser_up (cm)||||||15||14.3||||
     445||H_laser_down (cm)||||||||||||
     447EXP33 =>14h55 10.5 D (FPS 3) Problems with the camera PCO at the beginning. We need to compare the date of the first record with the trigger to obtain its time of start (~15h08).
     449Changement de vanne suite à une fuite.
     451EXP34  =>16h26 15 D (FPS 3) Problems with the camera FALCON at the  beginning. Delay of 201 frames with Dalsa2
     453EXP35  =>17h56 19 D (FPS 3) Problems with the camera FALCON at the  beginning. Several start of the trigger recorded are not representative of the start of the camera.
     459'''Thursday, 9 of March 2017'''
     462||H_coast (cm)||||19.5||19.7||18.2||
     463||H_laser_up (cm)||||17||16||15.5||||
     464||H_laser_down (cm)||||||||||||
     466Lumenera Settings
     473[[BR]]EXP36 =>[11h09:The 11h09]:50  The laser sheet before the wall pass through a clean (light) fluid layer without particles. This new option provides a significant increase of the intensity of illuminated particles in the experimental area !! Good option to keep for the next experiments.
     475Diaphragm 9mm / flow rate 24 lit/min
     477EXP37 => 14h12:30
     479Diaphragm 11.5mm / flow rate 33 lit/min (?? strange value according to the previous fit)
     481The position of lumen era camera was changed for this experiment and new calibration done.
     483Very nice upstream current with a well defined unstable wavelength on the steep slope.
     485EXP38 => 15h58
     487Diaphragm 13mm / flow rate 55 lit/min
     489Very nice upstream current with a well defined unstable wavelength on the steep slope. We test in the middle of the acquisition the laser sheet in the lower layer (-13cm). It confirms that the velocity in the lower layer is very weak.
     491'''Friday, 10 of March 2017'''
     494||H_coast (cm)||||20||20||19||
     495||H_laser_up (cm)||||19||17||16||||
     496||H_laser_down (cm)||||||||||||
     498Lumenera Settings
     509[[BR]]We start today with a frontal density current (like a buoyant river plume). In other words the injection of fresh water in a deepd fluid  layer of uniform density.
     511EXP39 start injection around =>09h20
     513Diaphragm 9mm / flow rate 24 lit/min
     515fps of PCO, DALSA, FALCON stays at 3 images/s
     517A very thin (small width) current flow along the wall, no apparent signature of instability or any meander formation . But due to the curvature of the laser sheet we didn't see what happens at the same depth everywhere... we are quite deep at the center (M0) of the wall while much closer to the surface at (M1 and M-1).
     519EXP40 =>10h06
     521Diaphragm 13mm / flow rate 54 lit/min
     523Always a stable density front with almost no impact of the bottom shelf bathymetry...
     525We forget to take a density profile inside the current ! grrr...
     527EXP41 =>10h!37:55
     529fps of PCO, DALSA, FALCON was changed to 10 images/s and for all the records below
     531Diaphragm 15mm / flow rate  75lit/min
     533Always a stable density front with a slight change on the width of the current from steep to gentle slope, but not sure that it is note due to the curvature of the laser sheet ...
     535EXP42 =>11h!05:55
     537Diaphragm 17mm / flow rate 88 lit/min
     539Always a stable density front with a slight change on the width of the current from steep to gentle slope, but not sure that it is note due to the curvature of the laser sheet ...
     541Several density profiles were done inside the coastal front.
     543EXP43 =>14h!32:30
     545Diaphragm 19mm / flow rate  120 lit/min
     547A roughly stable front with some few meanders or stretched eddies at the edge of the front.
     549'''Wednesday, 15 of March 2017'''
     552||H_coast (cm)||||6.6||6.9||7||
     553||H_laser_up (cm)||||4.6||2.1||4||||
     554||H_laser_down (cm)||||||||||||
     556Lumenera Settings
     564EXP44 =>08h48 fin 9h28
     566Diaphragm 9mm / flow rate 24 lit/min
     568A clear stagnation point occurs along the coast where the bathymetric slope changes. The impact of the bottom bathymetry is significantly stronger now.
     570On the other hand with the 40s period of rotation there is more vibration of the platform which may affect the stability of the recording cameras.
     572EXP45 =>10h10 fin ?
     574Diaphragm 13mm / flow rate 48 lit/min
     576The coastal current (and the eddies) pass over the bathymetric change without any stagnation points
     578EXP46 => 11h49 end 12h26
     580Diaphragm 10.5mm / flow rate 34.5 lit/min
     582Here again a stagnation point appears at the change of the bathymetric slope and the coastal flow is strongly reduced along the wall on the gentles slope area.
     584EXP47 =>14h11  end 15h00
     586Diaphragm 7.5mm / flow