Changes between Version 45 and Version 46 of WikiStart

Sep 15, 2017, 2:13:28 PM (3 years ago)



  • WikiStart

    v45 v46  
    214214The reflection is now ok and we can start our experiments!
    216 '''Test experiment EXP01'''
     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.
    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.'''
    228 '''Experiment EXP02'''
     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! '''
    234232The cameras are fixed now and taking every photo and the particles are spread out in the ambient water.
    236 '''Experiment EXP03'''
     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!
    240237The current reached the first corner after about 1 minute, and  the trough corner after about 3 minutes.
    242 '''Experiment EXP04'''
     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).
    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]]''''''''''
    250 '''Experiment EXP05'''
     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).
    260255The current was at the first corner about 1 minute after the valve was opened.
    262 '''Experiment EXP06'''
     257=== '''Experiment EXP06''' ===
    264258The squared cornes were inserted - the land corner was fastened with tape and the submerged corner with a screw..
    268262The flow separated at the first corner and turned at the second corner.
    270 The vertical scann was started 15 min after the valve was opened.
    272   '''Experiment EXP07'''
     264The vertical scann was started 15 min after the valve was opened.''''''
     266=== '''Experiment EXP07''' ===
    274267An eddy initially forms behind the first corner, but it then disappears.
    280273'''7.6 Thursday 14 September'''
    282 '''Experiment EXP08'''''''
     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.
    292284This is to avoid shaking of laser.
    294 '''Experiment EXP09'''
     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.
    300291The laser sheets were started 26 minutes after the valve was opened.
    302 '''Experiment EXP10'''
     293=== '''Experiment EXP10''' ===
    304294The flow rate is increased, there are again a lot of bubbles.
    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
    312 '''Experiment EXP11'''
     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.
    337326Note: After Exp11 they realized that there was water in the laser, they had to go and move it up.
    339 '''Experiment EXP12'''
     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.
    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.
    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.
    361 '''Experiment 14'''
    363 We increase the influx to a desired value of 80 l/min with still the higher water level and increased rotation rate.
    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.
     352Due to the high flux rate, we use an exposure time of 30 ms.
    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.