Changes between Version 143 and Version 144 of WikiStart

Oct 6, 2016, 1:40:53 PM (4 years ago)

Thursday Sept 22 added


  • WikiStart

    v143 v144  
    145145'''Thursday, September 22nd 2016'''
     147Experiment name: fixstr_2209a, b. File names: fixstr1_2909a, fixstr1_2909b. Location: Position X1 (75% down straight section, 58 cm upstream from the end of the straight section). Density excess 19.2 kg/m^3^.
     149Before the experiments samples were collected from the storage tanks which store 10 kg/m^3^ and 20 kg/m^3^ salt water in order to check the density. Also, samples from the base and the top of the rotating Coriolis tank were collected. No laser was used since the quality of the water was not good enough.
     151fixstr1_2909a: Flow rate started with 6 L/s for about 16 minutes. Siphon sample Set !#1 was collected around 5 minutes after the start of the experiment for 1 minute. After 7 minutes, a sample was collected from the tank on the third floor where salt water enters from the storage tank. Then the flow rate was increased to 8 L/s. At around 16 minutes constant flow rate was reached and a second set of siphon samples were collected at about 19 minutes for 1 minute deviation. The flow rate then was increased to 10 L/s, but since it took a long time to become constant the UVP stopped. So a second experiment was conducted with a flow rate 10 L/s. Also, the Nikon Camera took 2 videos, 10 minutes each one at the start and one almost right at the end.
     153fixstr1_2209b: Flow rate was 10 L/s and the total experiment timing was 16 min. The flow rate became constant after about 7 minute, so potentially it was not constant before. One siphon sample was collected at 4:27 for one minute deviation. After measuring the density, it was concluded that the density of the inlet box is much lower than 20 kg/m^3^ meaning a lot of mixing is occurring there. Therefore, there are two issues that need to be considered for future experiments.
     1551. How to control the density of the inlet box and reduce mixing.
     1582. Start every experiment with a constant flow rate, which takes at least 5 min to occur.
    166179It took 2.5 min for the flow rate to stabilize. The ADV was initialized 5 minutes after flow stabilized. The ADV needed more seeding to improve the signal-to=noise ratio. The !GoPro in the inlet box showed a lot of mixing between the current and the ambient which explains the decrease in density in the gravity current in the inlet box. The suggestion was to reduce the inlet box volume to reduce the time to reach steady-state density (by reduce the flushing time).
    169181'''Tuesday, September 27th 2016'''