Changes between Version 56 and Version 57 of WikiStart

Timestamp:

Sep 20, 2017, 6:00:38 PM (7 years ago)

Author:

steiger5na

Comment:

--

WikiStart

@@ -425 +425 @@
 Observations: The flow was much more established, when it reached the view of PCO1. Regular waves occurred along the slope until it reached the first corner. Almost the whole current turned south into the trough.
 
-Notes: The images for HS were accidently only taken for 7min, but restarted again for 7 min (EXP18_B).
+Notes: The images for HS were accidentally only taken for 7min, but restarted again for 7 min (EXP18_B).
 
 === Experiment EXP19 ===
@@ -460 +460 @@
 
 === Experiment EXP24 ===
-We increased the water level to 70 cm and kept the corner. The plan was to do one experiment with Q=110 l/min, but because that was so similar to 80 l/min before, we decided to increase it to 130 l/min (diaphragme 19.5mm). We kept the small dt = 50 ms and the E = 20 ms. 
+We increased the water level to 70 cm and kept the corner. The plan was to do one experiment with Q=110 l/min, but because that was so similar to 80 l/min before, we decided to increase it to 150 l/min (diaphragme 19.5mm). Measurements of the flow rate gave a value of Q = 150 l/min. We kept the small dt = 50 ms and the E = 20 ms.
 
 Observations: The current entered the trough in a very large radius and builds an anti-cyclone on the shelf. Only a very small part of the current went straight, passing the trough.
+
+Note: '''During this and the following experiments with a water level of 70 cm, we didn't convert the flow rate relative to the source area below the water level! So, all these experiments give a smaller velocity compared to the same experiments with the lower water level.'''
+
+=== Experiment EXP25 ===
+The desired flow rate was reduced to 80 l/min (diaphragme 16mm), which gave a flow rate of 94 l/min.   
+
+Observations: At the slope current towards the first corner, large vortices were created. The inflow into the trough was not very strong and more turbulent. Half of the flow passed the trough along the slope.
+
+=== Experiment EXP26 ===
+The desired flow rate was reduced to 50 l/min (diaphrame 12.6mm), which gave a flow rate of 54 l/m. The images were started after the flow started, because it takes a long time for the flow to reach the view of the first camera.
+
+Note: The images for the first HS were taken for too short time (10 min), so that the flow was not established yet. We restarted and took more images for 5 min (saved in EXP26_B).
+
+Note: We added larger particles (60 micron) into the inflow water (instead of the 30 micron), because Joel suggested that it may be better for the PIV. The particles in the ambient water were still the same.
+
+Observations: The current enters the trough in a very large radius.
+
+=== Experiment EXP27 ===
+This is a repetition of EXP26 without the corner. The measured flow rate was 53.2 l/min.
+
+Observations: Compared to EXP26 with the corner, the current enters the trough in a much smaller radius, following neatly the topography. After waiting, also a large part flow straight.
+
+Note: In the beginning of the experiment, there were still a lot of particles in the ambient water.
+
+=== Experiment EXP28 ===
+The desired flow rate was increased to 80 l/min (16mm), which gave a measured flow rate of 92.4 l/min.
+
+We had to do this experiment twice (first one was overwritten), because the honeycomb in the source loosened in the beginning of the first time and released a lot of clustered particles/bubbles that spread over the whole flow area. The source had to be fixed and we didn't have the time to completely wait until all the clusters escaped the tank. During the second round of this experiment, there were therefore still some of the clusters moving into the sight of the cameras.
+
+Observations: The largest part of the current continued straight, but there was quite a strong return flow across the trough from the western corner of the trough to the southeastern corner of the trough.
 
   '''' ''6 - Table of Experiments: '''''