Changes between Version 46 and Version 47 of WikiStart

Sep 15, 2017, 2:15:31 PM (4 years ago)



  • WikiStart

    v46 v47  
    106106All  images from the experiments will be stored in the directory  /fsnet/projects/coriolis/2017/17ICESHELF/DATA under the name for the  experiment.
    108 == '''4.1 Calibration for shelf break experiments''' ==
     108== 4.1 Calibration for shelf break experiments ==
    109109The images for PIV (PC01, PC02) are calibrated from images of a horizontal grid, in 3D with an inclined grid (tilted angles) and in the vertical (NAME OF CAMERA!) for the camera fixed on the tank wall.[[BR]]The calibrated images with the grids are stored in 0_REF_FILES with the [[BR]]- 2D calibration in the directory CALIB_07_09[[BR]]- 3D calibration in the directory CALIB_07_09_3D[[BR]]- Vertical calibration in the directory CALIB_VERTICAL_08-09
    158158=  =
    159159= 7 - Diary: =
    160 == '''7.1 Thursday 07 September''' ==
     160== 7.1 Thursday 07 September ==
    161161The cameras still have to be adjusted. After that is done, we take photos with the calibration grid in the horizontal and in 3D with both cameras that are fixed on the roof. With PIV, we conduct the calibration of both cameras as described in 4.1.
    163 == '''7.2 Friday 08 September''' ==
     163== 7.2 Friday 08 September ==
    164164To verify the calibration, we took photos with both cameras with one ruler to see if the calibrations of the cameras agree (which it does!). Then, we added a wall into the tank to prevent the water of the freshwater experiments to return to the source. The laser height was adjusted.
    207207When turning to the horizontal cameras it was decided that sloping topography gave too many uncontrolled reflections that made it unsafe to increase the intensity. To remove these,parts of the bathymetry has to be Paint in black. The tank was set to empty during the night, while recycling the water.
    209 == '''7.4 Tuesday 12 September''' ==
     209== 7.4 Tuesday 12 September ==
    210210The bathymetry has been painted black, a pipe has been introduced into the source and the drain has been lowered to that it can be used also for 60 cm water depth.
    214214The reflection is now ok and we can start our experiments!
    216 === '''Test experiment EXP01''' ===
     216=== Test experiment EXP01 ===
    217217We conducted experiments with a long HS from the beginning after turning on the influx (EXP_01). The influx was 41 L/min with a diaphragma of 12.6 mm diameter. The influx water had a density of 998.2 and was enriched with particles of size 30mikrom. The laser sheet was at 11cm over the trough, 4 cm over the shelf, so at 54 cm when the laser setting was at 650. We decreased it to 640 to have the laser sheet at 55 cm. Water Level (supervision - this changes witha few mm when People come enter/leave the rotating Office) was at 58.4 cm. The exposure time of the cameras was at 50ms  and the time interval 500 ms.
    225225Data check: We checked these first results with the PIV and decided to decrease the exposure time to get sharper images of the particles. With PCO2, the flow around the curvature can be captured with the PIV, but on PCO1 the PIV is not very good, because the flow is more turbulent and more 3 dimensional. We decide to decrease the time between the photos. '''Later we realized that the cameras only took every second photo, so with a time interval of 1000ms - > useless PIV.'''
    227 === '''Experiment EXP02''' ===
     227=== Experiment EXP02 ===
    228228We repeated the HS with a reduced time to 200 ms between the photos and and exposure time of 30ms'''. We realized afterwards that the cameras only took every second photo, so with a time interval of 400ms! '''
    230 '''7.5 Wednesday 13 September'''
     230== 7.5 Wednesday 13 September ==
    232231The cameras are fixed now and taking every photo and the particles are spread out in the ambient water.
    234 === '''Experiment EXP03''' ===
     233=== Experiment EXP03 ===
    235234The setup is still the same as for the previous experiments with 200ms time difference between the photos (this time working!) and particles in the ambient water. This time, we measured the flow rater AFTER the experiment and it was $Q = 50 l/min$ (measurements repeated twice), as expected. There are still bubbles coming out of the source!
    237236The current reached the first corner after about 1 minute, and  the trough corner after about 3 minutes.
    239 === '''Experiment EXP04''' ===
     238=== Experiment EXP04 ===
    240239We started a new experiment at !10:31 with a reduced flow rate of about $Q = 20 l/min$ (diaphrama diameter of 6.8 mm). The first HS is run for 15 min n(!10:31- !10:46). The flow field was still evolving so we extended the five more minutes of hs (!10:51-10:56  this data are stored in EXP04_B) before we started the scan ( !10:59).
    244243Observations: The bubble at the source disappeared due to the lower flow rate. The current follows along the slope and turns left at the 2nd curvature into the trough. After the 15 min after the flow was turned on, the flow bifurcates at the continental coast and at the trough and fills up the trough. The return flow does not follow along the upstream slope of the trough, but occurs in the middle of the trough. The main current along the slope is getting wider with time. [[BR]]''''''''''
    246 === '''Experiment EXP05''' ===
     245=== Experiment EXP05 ===
    247246The vertical velocity of the laser was decreased and the timestep between the first and the second image at each level increased to 1s (first image will be discarded).
    255254The current was at the first corner about 1 minute after the valve was opened.
    257 === '''Experiment EXP06''' ===
     256=== Experiment EXP06 ===
    258257The squared cornes were inserted - the land corner was fastened with tape and the submerged corner with a screw..
    262261The flow separated at the first corner and turned at the second corner.
    264 The vertical scann was started 15 min after the valve was opened.''''''
    266 === '''Experiment EXP07''' ===
     263The vertical scann was started 15 min after the valve was opened.'''''''''''
     265=== Experiment EXP07 ===
    267266An eddy initially forms behind the first corner, but it then disappears.
    273272'''7.6 Thursday 14 September'''
    275 === '''Experiment EXP08''' ===
     274=== Experiment EXP08 ===
    276275The squared corners are still on, for the first 3 minutes of the horizontal slice the light in the entrance was turned on.
    284283This is to avoid shaking of laser.
    286 === '''Experiment EXP09''' ===
     285=== Experiment EXP09 ===
    287286The squared corners are removed and the flow rate is reduced. There were a lot of particles in the inflow in the beginning.
    291290The laser sheets were started 26 minutes after the valve was opened.
    293 === '''Experiment EXP10''' ===
     292=== Experiment EXP10 ===
    294293The flow rate is increased, there are again a lot of bubbles.
    300299A smaller part continued to the corner of the slope and the depression (after 3minutes) and entered the depression, circulated along the topography and escaped by the western side of the depression
    302 === '''Experiment EXP11''' ===
     301=== Experiment EXP11 ===
    303302The water level is increased by 10 centimeters to 68.5 cm. With the higher water level, we need to calculate new flow rates with the ration of the outflow area before and after the higher water level. Now, we are aiming to a flow rate of 33 l/min, which corresponds to the 20 l/min for the lower water level.
    326325Note: After Exp11 they realized that there was water in the laser, they had to go and move it up.
    328 === '''Experiment EXP12''' ===
     327=== Experiment EXP12 ===
    329328This experiment was the same as EXP11 with a water level of 68.5 cm but with the corner. The expected flowrate was 33 l/min and the measured flowrate was 34.6 l/min.
    347346Note: The source is leaking, which created bubbles and a little "waterfall" due the the water surface difference inside and outside the source. Thomas fixed it by putting a wooden block in front of the leakage.
    349 === '''Experiment EXP14''' ===
     348=== Experiment EXP14 ===
    350349We increase the influx to a desired value of 80 l/min with still the higher water level and increased rotation rate.