Changes between Version 46 and Version 47 of WikiStart
- Timestamp:
- Sep 15, 2017, 2:15:31 PM (7 years ago)
Legend:
- Unmodified
- Added
- Removed
- Modified
-
WikiStart
v46 v47 106 106 All images from the experiments will be stored in the directory /fsnet/projects/coriolis/2017/17ICESHELF/DATA under the name for the experiment. 107 107 108 == '''4.1 Calibration for shelf break experiments'''==108 == 4.1 Calibration for shelf break experiments == 109 109 The 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_08-09 110 110 … … 158 158 = = 159 159 = 7 - Diary: = 160 == '''7.1 Thursday 07 September'''==160 == 7.1 Thursday 07 September == 161 161 The 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. 162 162 163 == '''7.2 Friday 08 September'''==163 == 7.2 Friday 08 September == 164 164 To 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. 165 165 … … 207 207 When 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. 208 208 209 == '''7.4 Tuesday 12 September'''==209 == 7.4 Tuesday 12 September == 210 210 The 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. 211 211 … … 214 214 The reflection is now ok and we can start our experiments! 215 215 216 === '''Test experiment EXP01'''===216 === Test experiment EXP01 === 217 217 We 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. 218 218 … … 225 225 Data 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.''' 226 226 227 === '''Experiment EXP02'''===227 === Experiment EXP02 === 228 228 We 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! ''' 229 229 230 '''7.5 Wednesday 13 September''' 231 230 == 7.5 Wednesday 13 September == 232 231 The cameras are fixed now and taking every photo and the particles are spread out in the ambient water. 233 232 234 === '''Experiment EXP03'''===233 === Experiment EXP03 === 235 234 The 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! 236 235 237 236 The current reached the first corner after about 1 minute, and the trough corner after about 3 minutes. 238 237 239 === '''Experiment EXP04'''===238 === Experiment EXP04 === 240 239 We 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). 241 240 … … 244 243 Observations: 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]]'''''''''' 245 244 246 === '''Experiment EXP05'''===245 === Experiment EXP05 === 247 246 The 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). 248 247 … … 255 254 The current was at the first corner about 1 minute after the valve was opened. 256 255 257 === '''Experiment EXP06'''===256 === Experiment EXP06 === 258 257 The squared cornes were inserted - the land corner was fastened with tape and the submerged corner with a screw.. 259 258 … … 262 261 The flow separated at the first corner and turned at the second corner. 263 262 264 The vertical scann was started 15 min after the valve was opened.'''''' 265 266 === '''Experiment EXP07'''===263 The vertical scann was started 15 min after the valve was opened.''''''''''' 264 265 === Experiment EXP07 === 267 266 An eddy initially forms behind the first corner, but it then disappears. 268 267 … … 273 272 '''7.6 Thursday 14 September''' 274 273 275 === '''Experiment EXP08'''===274 === Experiment EXP08 === 276 275 The squared corners are still on, for the first 3 minutes of the horizontal slice the light in the entrance was turned on. 277 276 … … 284 283 This is to avoid shaking of laser. 285 284 286 === '''Experiment EXP09'''===285 === Experiment EXP09 === 287 286 The squared corners are removed and the flow rate is reduced. There were a lot of particles in the inflow in the beginning. 288 287 … … 291 290 The laser sheets were started 26 minutes after the valve was opened. 292 291 293 === '''Experiment EXP10'''===292 === Experiment EXP10 === 294 293 The flow rate is increased, there are again a lot of bubbles. 295 294 … … 300 299 A 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 301 300 302 === '''Experiment EXP11'''===301 === Experiment EXP11 === 303 302 The 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. 304 303 … … 326 325 Note: After Exp11 they realized that there was water in the laser, they had to go and move it up. 327 326 328 === '''Experiment EXP12'''===327 === Experiment EXP12 === 329 328 This 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. 330 329 … … 347 346 Note: 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. 348 347 349 === '''Experiment EXP14'''===348 === Experiment EXP14 === 350 349 We increase the influx to a desired value of 80 l/min with still the higher water level and increased rotation rate. 351 350
