Changes between Version 242 and Version 243 of WikiStart


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Timestamp:
Oct 19, 2016, 6:08:13 PM (4 years ago)
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peakall3je
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    v242 v243  
    124124== 3.2 Definition of time origin and instrument synchronisation ==
    125125
    126 This section relates to the main experiments, and not the test experiments (see diary entries for details of earlier experiments). Conductivity as measured in the inlet box (Probe C1) is seen to vary initially due to mixing within the input box, and because a higher input rate is used in the first minute of the experiment (~11-13 L/s in the main experiments – see Section 6) than later in the flow (~6 L/s). This initial pulse is intended to help to clear fluid out of the inlet box. The time origin is judged to be that point at which the value of this conductivity probe (C1) becomes approximately constant. The timings and synchronisation of the ADV, UVP and the Siphons are controlled with the aid of a stopwatch which is started at the time origin. PIV is then initiated soon after the time origin (approximately 0 minutes) to approximately 10 minutes run time. The timing of PIV initiation can be determined retrospectively, relative to the time origin, because the traverse initiation (that runs the ADV) is specifically linked to the time origin (ADV measurements start at 15 minutes and runs to 35 minutes), and both the traverse and the PIV are tied into the main control software. Thus knowing the time difference between the traverse initiation and the PIV initiation, and subtracting this from 15 minutes provides the PIV initiation relative to the time origin. The UVP and Siphon data are independent as their outputs are not directly tied into the Coriolis control software in the same way that the traverse is. Siphons are initiated after 5 minutes, and the cross-stream UVPs are started at 5 minutes (run until 15 minutes), whilst the downstream UVPs are started at 25 minutes are run until 35 minutes.
     126This section relates to the main experiments, and not the test experiments (see diary entries for details of earlier experiments). Conductivity as measured in the inlet box (Probe C1) is seen to vary initially due to mixing within the input box, and because a higher input rate is used in the first minute of the experiment (~11-13 L/s in the main experiments – see Section 6) than later in the flow (~6 L/s). This initial pulse is intended to help to clear fluid out of the inlet box. The time origin is judged to be that point at which the value of this conductivity probe (C1) becomes approximately constant. The timings and synchronisation of the ADV, UVP and the Siphons are controlled with the aid of a stopwatch which is started at the time origin. PIV is then initiated soon after the time origin (approximately 0 minutes) to approximately 10 minutes run time. The timing of PIV initiation can be determined retrospectively, relative to the time origin, because the traverse initiation (that runs the ADV) is specifically linked to the time origin (ADV measurements start at 15 minutes and runs to 35 minutes), and both the traverse and the PIV are tied into the main control software. Thus knowing the time difference between the traverse initiation and the PIV initiation, and subtracting this from 15 minutes provides the PIV initiation relative to the time origin. The UVP and Siphon data are independent as their outputs are not directly tied into the Coriolis control software in the same way that the traverse is. Siphons are initiated after 5 minutes, and the cross-stream UVPs are started at 5 minutes (run until 15 minutes), whilst the downstream UVPs are started at 25 minutes are run until 35 minutes. For 19/10 and 20/10 files the start of the PIV integrates directly with the time origin, all other aspects as before.
    127127
    128128== 3.3 Requested final output and statistics ==