The input file Level-Base.inp models a standpipe with forced liquid inflow at 14 m/s, and a drain with velocity driven by the height of water above. Run the problem and plot the water level to convince yourself that it has achieved a steady state. Make a hw6 directory, and copy the file trcdmp to it with the name "BaseDump". If jEdit is able to submit TRACE jobs for you open Level-Step.inp, and use the SNAP plugin to execute the deck. When the execution monitor's "Submit Calculation" window appears, fill in the "Restart File" box with the full path to your "BaseDump" file. If this capability is not available, follow the instructions in class to run TRACE from a Bash shell (typed commands). Plot the results. Based on the plot select either the Cohen and Koon or Ziegler-Nichols method, and use what you learned from the lecture on control theory to set the gain and integration time scale on a PI controller that will drive the level to 7.5m. I've provided you with templates for both proportional and PI controllers that start from "BaseDump".
Show all and
explain all results relevant to selection of the initial
gain and integration time scale for the PI controller. Once you
have these values, make four more runs with base gain and integration
time multiplied and divided by 2.
Plot level vs. time from 0 to 100 seconds for all five of these runs .
Select the result that drives the water level to within 0.01m of 7.5m
in the least amount of time (show
any detailed plots you need to make this selection). If it
is not the original, make one
study on the variation (half and double) of parameters from the
previous run with best
results. This will give you three
more curves of level vs. time to plot in addition to your previous best.
Again document your selection of best parameters.
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