Changes between Version 45 and Version 46 of WikiStart


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Timestamp:
Sep 15, 2017, 2:13:28 PM (3 years ago)
Author:
steiger5na
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  • WikiStart

    v45 v46  
    214214The reflection is now ok and we can start our experiments!
    215215
    216 '''Test experiment EXP01'''
    217 
     216=== '''Test experiment EXP01''' ===
    218217We 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.
    219218
     
    226225Data 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.'''
    227226
    228 '''Experiment EXP02'''
    229 
     227=== '''Experiment EXP02''' ===
    230228We 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! '''
    231229
     
    234232The cameras are fixed now and taking every photo and the particles are spread out in the ambient water.
    235233
    236 '''Experiment EXP03'''
    237 
     234=== '''Experiment EXP03''' ===
    238235The 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!
    239236
    240237The current reached the first corner after about 1 minute, and  the trough corner after about 3 minutes.
    241238
    242 '''Experiment EXP04'''
    243 
     239=== '''Experiment EXP04''' ===
    244240We 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).
    245241
     
    248244Observations: 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]]''''''''''
    249245
    250 '''Experiment EXP05'''
    251 
     246=== '''Experiment EXP05''' ===
    252247The 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).
    253248
     
    260255The current was at the first corner about 1 minute after the valve was opened.
    261256
    262 '''Experiment EXP06'''
    263 
     257=== '''Experiment EXP06''' ===
    264258The squared cornes were inserted - the land corner was fastened with tape and the submerged corner with a screw..
    265259
     
    268262The flow separated at the first corner and turned at the second corner.
    269263
    270 The vertical scann was started 15 min after the valve was opened.
    271 
    272   '''Experiment EXP07'''
    273 
     264The vertical scann was started 15 min after the valve was opened.''''''
     265
     266=== '''Experiment EXP07''' ===
    274267An eddy initially forms behind the first corner, but it then disappears.
    275268
     
    280273'''7.6 Thursday 14 September'''
    281274
    282 '''Experiment EXP08'''''''
    283 
     275=== '''Experiment EXP08''' ===
    284276The squared corners are still on, for the first 3 minutes of the horizontal slice the light in the entrance was turned on.
    285277
     
    292284This is to avoid shaking of laser.
    293285
    294 '''Experiment EXP09'''
    295 
     286=== '''Experiment EXP09''' ===
    296287The squared corners are removed and the flow rate is reduced. There were a lot of particles in the inflow in the beginning.
    297288
     
    300291The laser sheets were started 26 minutes after the valve was opened.
    301292
    302 '''Experiment EXP10'''
    303 
     293=== '''Experiment EXP10''' ===
    304294The flow rate is increased, there are again a lot of bubbles.
    305295
     
    310300A 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
    311301
    312 '''Experiment EXP11'''
    313 
     302=== '''Experiment EXP11''' ===
    314303The 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.
    315304
     
    337326Note: After Exp11 they realized that there was water in the laser, they had to go and move it up.
    338327
    339 '''Experiment EXP12'''
    340 
     328=== '''Experiment EXP12''' ===
    341329This 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.
    342330
     
    344332
    345333== 7.7 Friday 15 September ==
    346 === Experiment 13 ===
     334=== Experiment EXP13 ===
    347335During night, we increased the rotation rate to get a rotation period of 30s! We kept the corners.
    348336
     
    359347Note: 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.
    360348
    361 '''Experiment 14'''
    362 
    363 We increase the influx to a desired value of 80 l/min with still the higher water level and increased rotation rate.
    364 
    365 Due to the high flux rate, we use an exposure time of 30 ms.
     349=== '''Experiment EXP14''' ===
     350We increase the influx to a desired value of 80 l/min with still the higher water level and increased rotation rate.
     351
     352Due to the high flux rate, we use an exposure time of 30 ms.
    366353
    367354Notes: The water level increased constantly. After this experiment, we had to adjust the sink to let out more water. It takes some time, so we had to wait until the water level was good again.