Advection Dispersion Modelling: Difference between revisions
Content deleted Content added
Tuflowduncan (talk | contribs) |
|||
| (9 intermediate revisions by 4 users not shown) | |||
Line 2:
TUFLOW’s Advection Dispersion (AD) Module is an extension of the TUFLOW Classic/HPC engines. It adds to the hydrodynamic capabilities of TUFLOW Classic/HPC by simulating depth-averaged, two and one-dimensional constituent fate and transport. An example of such a constituent might include salinity. Both dissolved and particulate constituents can be simulated. TUFLOW AD takes depth and velocity fields computed by the TUFLOW Classic and HPC solvers and uses this information, together with initial and boundary conditions, to simulate the advection and dispersion of user-defined constituents.
TUFLOW AD is specifically oriented towards such analyses in systems including coastal waters, estuaries, rivers, floodplains and urban areas. The AD module is discussed in detail in the <u>[https://
=Model Development=
Line 19:
<li>Set up the boundary condition tables (.csv file(s)) to define the time-varying constituent concentrations at any input boundaries.
<ul><li>Set up the constituent boundary condition table(s) in the “bc_dbase” folder
[[File:EG17 conc 001.png]]<br></ul>
<li>Set up up the boundary condition database (.csv file)
Line 63:
For example, a model with direct rainfall over the entire domain applies a passive tracer via 2d source area (2d_sa) polygons. The output can be set up to identify areas with tracer concentrations above a certain threshold, distinguishing firewater extents from other inundated areas. Areas outside of this represent zones with zero tracer concentration. Tracers can also include decay and settling parameters for added flexibility. This method not only simplifies the process but also ensures compliance with CIRIA (Construction Industry Research and Information Association) guidance by integrating rainfall and firewater scenarios into a single simulation.
== What guidance is available for Non-Newtonian
The Non-Newtonian Mixing Exponents (m, o, and p) were introduced in the 2023-03-AC release to improve how TUFLOW models non-Newtonian fluids. These exponents control how yield stress and density change as fluid concentration varies.
Line 78:
Currently, there is no guidance for dispersion coefficients when mixing pure water with non-Newtonian fluids. Suitable values should be determined based on laboratory tests or studies specific to the fluid being modelled.
== What are the limitations of the Advection Dispersion module when modelling Non-Newtonian flow through 1D elements
When using the Advection Dispersion module for non-Newtonian flow in models that include 1D elements, the following simplifications and limitations apply:
Line 90:
These limitations mean that while the AD module can be used in models with 1D elements, it does not fully capture the complexities of non-Newtonian fluid behaviour in those elements. If higher accuracy is required, 2D elements where non-Newtonian properties are more comprehensively represented may be considered.
== Can the Advection Dispersion module be used in a model to simulate salinity? ==
Yes, the Advection Dispersion module can be used with models to simulate salinity transport, as long as the system is relatively well mixed vertically.
{{Tips Navigation▼
TUFLOW HPC is a 2D shallow water equation solver, so it does not account for vertical salinity gradients. This means it is best suited for rivers, shallow lakes, and estuaries where haloclines are weak or absent. Different boundary inflows can be assigned varying time series of salinity concentrations, and the module will simulate how these mix over space and time.
If the system has strong density stratification or distinctly three dimensional flow behaviour, a fully 3D solver such as TUFLOW FV is recommended.
== Can the Advection Dispersion module simulate pollutant runoff and transport from catchments? ==
Yes, the Advection Dispersion module can also be used to simulate pollutant runoff from catchments. This includes modelling the generation, transport, and fate of pollutants such as suspended sediment, nitrogen, and phosphorus.
Pollutants can be generated based on modelled bed shear stress, then transported through the domain using the flow field. The model can also apply decay and settling rates as part of the simulation.
The TUFLOW CATCH module is recommended to simulate pollutant runoff and transport from catchments. See the <u>[https://www.tuflow.com/products/tuflow-catch-module/ TUFLOW Website]</u> for further information.
▲<br>{{Tips Navigation
|uplink=[[ TUFLOW_Modelling_Guidance | Back to TUFLOW Modelling Guidance]]
}}
| |||