1D river simulations - options tab

Option

Description

Direct Method Transcritical solver

Performs full supercritical and transcritical simulation (available in Direct Method Steady-State only)

Automated Preissmann Slot for River Sections

Adds a triangular slot in the base of all river sections in the model to aid stability. Slot dimensions are width pswide and depth psdeep (see Advanced Parameters tab)

Use Sediment Module

Perform Flood Modeller mobile bed simulation (Flood Modeller Sediment Transport Add-on licensees only; unsteady mode (Fixed Timestep) only)

Write Quality File

(Flood Modeller Quality Add on licensees only). Writes hydraulics parameters to results file for subsequent use with an Water Quality Add-On simulation.

Control Unit Outputs

Writes control unit data to *.zzo file (Control Module only)

Matrix Singularity Check

Performs matrix structure check prior to solving linearised flow equations

Perform warm up start

Runs extra timesteps at the simulation start time, gradually ramping the initial conditions towards the boundary conditions. Improves the convergence at the beginning of simulations with poor or inappropriate initial conditions. Requires a Warm-up time to be specified in the Times tab

Run at Lower Priority

Sets the Windows process priority for the simulation to "Below Normal" to allow other Windows applications to run concurrently at a higher priority

Output Breach Profiles

Outputs breach unit profiles to zzd file (breach option not yet available in Flood Modeller GUI v2.1)

Automatic Shutdown

Closes the run windows down at the end of a simulation without prompting for diagnostic file viewing, etc

Decreasing Conveyance Check

Checks that river section conveyance increases with increasing water levels

Suppress Windows Output

Suppresses run time information windows

Perform Extra Timesteps at the beginning of a run

Performs six extra pseudo-timesteps before the first model timestep¹ to aid initial stability (disabled for steady direct run type)

Output breach profiles

Outputs Flood Modeller interpretation of user defined breach profiles (from breach units included in model. Data are written as series of x,y values in the output file.

Steer starting pumps toward user rating

Encourages Flood Modeller to utilise the user input segment of pump rating curve when a pump is activated during simulation (as opposed to equivalent backflow characteristic that Flood Modeller will define from rating curve data). By default this option is ticked active as this is the recommended setting.

Coarse bridge section property interpolation

If selected, bridge section properties are interpolated every 2% of the bridge section height including the vertical extension dfloodb. (If unselected, dfloodb is not included in this). Provided for backwards compatibility with versions 2.2 and earlier

Output at start time

If 'Initial Conditions', the results output at the Start Time are replicated from the initial conditions; if 'Calculated', then they are obtained from the results after the dummy timestepping at the start time (effectively the '0th' timestep).