When the user creates a new boundary condition one of the options available is option of type 8, Jet/plume. The form for editing the Jet/plume BC is shown in Jet/Plume Boundary Condition Editor. EFDC+ has been enhanced to work smoothly with the EE defined jet/plume settings.
Although similar to a flow boundary condition or withdrawal/return user interfaces, the settings for jet/plume boundary conditions are unique to this boundary condition. In the Jet/Plume Type drop-down menu the user specifies the flow data of a jet plume boundary to link to with the options of by-passing (ICAL=0), use a flow time series (QSER, ICAL=1), use a withdrawal return time series (W/R, ICAL=2). The user may also specify the frequency, in number of time steps, to update the JP calculations.
In the Diffuser Port Settings for Current Cell 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.
Figure 1 Modify/Edit Jet Plume BC Properties.
In the Control Parameters frame the user can set the #Elements, which is the maximum number of vertical computational elements along the length of the jet or plume. The maximum number of iterations is set in the #Iterations form.
With the Entrainment Option menu the user sets whether to use the maximum of shear and forced entrainment, or use the sum of shear and forced entrainment.
The Entrainment Stop menu provides three options for stopping the entrainment: stop at a specified number of elements (ISTJP=0), stop when the centreline penetrates the bottom or the surface (ISTJP=1), or stop when the boundary penetrates the bottom or the surface (ISTJP=2).
Other options include setting the Entrainment Error Criteria, and an adjustment factor for the Froude Number. EFDC can also write out a log file in various formats. Specify 1 for full ASCII, 2 for compact ASCII output at each update, 3 for full and compact ASCII output, and 4 for binary output.
Jet/Plume Boundary Condition Editor illustrates the temperature distribution in case of two diffusers in a weak flow stream.
Figure 2 Thermal Discharge from Multiport Diffusers using Jet Plume BC.