The form for the jet and plume boundary condition (Figure 1) features the Current Boundary Cell and Boundary Group Conditions frames similar to the Flow Boundary Conditions form. One difference is that in Current Boundary Cell for Jet/Plume, the user must define an upstream cell and a downstream cell simultaneously. In the Jet/Plume Type drop-down menu the user specifies the flow data of a jet plume boundary to link to with the time series options. These options include by-passing (ICAL=0), using a flow time series (QSER, ICAL=1), and using a withdrawal return time series (W/R, ICAL=2). The Flow Series and W/R Series in Flow Assignment for Cell is enabled according to the Jet/Plume type selected. The Diagnostics drop-down allows the user to select from display jet/plume stop conditions, and save jet/plume growth details. The Stop Plume Growth Option allows the simulation to stop after a certain number of elements, when the plume centreline penetrates, or when the plume edge penetrates. From release of EEMS11.2 WQ constituents may also be added to the plume.
In the Diffuser Port Settings frame the user may specify the settings for each discharge cell including the number of ports, the elevation, and the diameters of the port outlets, as well as the horizontal (azimuth) and vertical (altitude) angles. It should be noted that the flow in the QSER file is multiplied times the number of ports for the total flow for that BC cell. So for example, if a user has 10 ports with each port having a time series of 0.15 cms assigned for the jet, then the total flow is 10 * 0.15 cms = 1.5 cms.
The Maximum Number of Elements is mainly used for plume computation termination purposes. This means that plume growth will always stop when the Maximum Number of Elements is exceeded, which is before reaching the neutral buoyancy level or the plume reaches the surface (plume density less than ambient) or the bottom (plume density greater than ambient). It is important not to set this value too small as it will cause the computations to cease before the plume reaches the stop growth option.
The Maximum Number of Iterations is the maximum number of loops to calculate within each step of the element computation. Since there are multiple loops in the jet/plume computation, the actual computation can be time-consuming. Therefore, Number of Time Steps for Update lets users define after how many hydrodynamic time steps EFDC+ should compute the jet/plume result again and update the results. If simulating a uniform flow condition, the number of time steps for each update can be set much greater than in a more complex and changing environment.
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An adjustment factor for the Froude Number may also be set.
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Select Controlled using Time-Series from the drop-down box for Time Control in the Current Boundary Group frame.
Define the withdrawal cell and the return cell in the Current Boundary Cell frame.
In the W/R Flow and Concentration Rise/Fall Settings frame, select a time series from the drop-down box for Time Variable Series as shown in Figure 1.
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Figure 1. Controlled using time-series for Withdrawal/Return.
The selected time series can be edited by clicking the Edit button. This button also allows the creation of a new time series. After clicking the Edit button, the Boundary Data Series form will be displayed as shown in Figure 2. In this form, it shows all columns of the existing time series, and we can edit them in this form, to create a new time series by clicking the Add New button.
Time (days) is Julian time in days
Flow (m3/s) is the actual flow rate from the withdrawal cells to return cells
Other columns for salinity, temperature, dye, water quality, and chemical fate & transport, are different concentration values of the withdrawal cells to return cells. The positive delta values represent concentration in the return cells greater than the concentration of withdrawal cells and vice versa.
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Figure 2. Boundary Data Series form.