Initial condition for two-direction groundwater flow and heat dispersion in three directions

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1

Hi everyone,
Recently I’m trying to build a model which combines the groundwater_flow and heat_transport. In my model, since there is groundwater flow in both x and y coordinations, I’ve added an initial condition block for this. However, when I tried to run the model, it seems to get stuck in the initial_condition reading process for more than 4 hours (then I stopped the running). And also there is a heat dispersion in three dimensions. However, after checked a lot of examples and documentation, I found that in the medium properties block the heat dispersion only have two directions (longitudinal and transverse). My questions are as follows:

  1. Is the initial condition file for groundwater right?
  2. How can I set a three-dimensional heat dispersion for my medium properties?
  3. I have three material groups, thus, I generated three medium properties block and three solid properties block. Did I generate them in a right way?
    Thanks in advance for your feedbacks.

Cheers,
Haoyue

2

Since I’m a new user, I couldn’t upload files. So I will just copy the file contents here.

#MEDIUM_PROPERTIES
  $GEOMETRY_DIMENSION
   3
  $POROSITY
   1 0.3
  $TORTUOSITY
   1 1.0
  $STORAGE
   1 1e-05
  $PERMEABILITY_TENSOR
   ORTHOTROPIC 0.05 0.05 0.01
  $HEAT_DISPERSION
   1 0.5 0.025
#MEDIUM_PROPERTIES
  $GEOMETRY_DIMENSION
   3
  $POROSITY
   1 0.3
  $TORTUOSITY
   1 1.0
  $STORAGE
   1 1e-05
  $PERMEABILITY_TENSOR
   ORTHOTROPIC 12.5 12.5 2.5
  $HEAT_DISPERSION
   1 0.5 0.025
#MEDIUM_PROPERTIES
  $GEOMETRY_DIMENSION
   3
  $POROSITY
   1 0.3
  $TORTUOSITY
   1 1.0
  $STORAGE
   1 1e-05
  $PERMEABILITY_TENSOR
   ORTHOTROPIC 0.05 0.05 0.01
  $HEAT_DISPERSION
   1 0.5 0.025
#STOP
3 
#INITIAL_CONDITION
  $PCS_TYPE
   HEAT_TRANSPORT
  $PRIMARY_VARIABLE
   TEMPERATURE1
  $DIS_TYPE
   CONSTANT 285.0
  $GEO_TYPE
   DOMAIN
#INITIAL_CONDITION
  $PCS_TYPE
   GROUDNWATER_FLOW
  $DIS_TYPE
   FUNCTION
  $GEO_TYPE
   SUBDOMAIN
   3
   0 -0.00012493 * x - 0.00030378 * y + 0.268275
   1 -0.00012493 * x - 0.00030378 * y + 0.268275
   2 -0.00012493 * x - 0.00030378 * y + 0.268275
#STOP
4

Hi Haoyue,
I might not be able to answer all your questions since I’m mainly working with OGS6.
First, in the ICs for groundwater_flow, obviously the keyword PRIMARY_VARIABLE is missing. Second, the term “transverse” actually means perpendicular to the flow direction. Assuming that groundater flow direction is x- in your model, thus when the transverse dispersivity is given, it actually applies to both y- and z- directions.

Regards,
Boyan

5

Hi, Boyan
Thanks for your feedback. Indeed, I forgot to add a primary variable for the initial condition for groundwater flow. As for the explanation for heat dispersion, does it mean that the y and z- directions can only have the same heat dispersion value? Really appreciate for your replying. Besides, in my model, the water density would vary with the temperature. I’m confused about the setting of the numerics block. For example, I have no clue when I should use a ELE_GUASS_POINT and what it is for. Besides, when should I add non-linear-solver and COUPLED_PROCESS.
#FLUID_PROPERTIES
$FLUID_TYPE
LIQUID
$DENSITY
3 1000.0 298.0 -0.1
$VISCOSITY
1 0.0
$SPECIFIC_HEAT_CAPACITY
1 4183.0
$HEAT_CONDUCTIVITY
1 0.58
$PCS_TYPE
PRESSURE1
#STOP

#NUMERICS
$PCS_TYPE
GROUNDWATER_FLOW
$NON_LINEAR_SOLVER
PICARD 0.001 25 0.0
$LINEAR_SOLVER
2 1 0.001 1000 1.0 100 4
$COUPLING_CONTROL
LMAX 1e-06
$COUPLED_PROCESS
HEAT_TRANSPORT 1 3
#NUMERICS
$PCS_TYPE
HEAT_TRANSPORT
$LINEAR_SOLVER
2 1 1e-09 1000 1.0 1 4
$COUPLING_CONTROL
LMAX 1e-06
#STOP

Regards,
Haoyue

6

This is a good question. I did a quick search and found that in solute transport, dispersivity is sometimes differentiated among longitudinal, (horizontal) transverse and vertical directions (https://www.sciencedirect.com/topics/earth-and-planetary-sciences/dispersivity and http://www.sara.env.dtu.dk/-/media/Sites/Sara/Rapporter/Risikovurdering/dispersivity%20in%20aquifers-1%201.ashx). Although, vertical dispersivities are often quite small. But in heat transport, the common approach is to only acknowledge one “transverse” thermal dispersivity. My understanding is that unlike solute, heat has no mass and thus no gravity effects. Besides, transverse thermal dispersivity values are very hard to measure in practice and is often estimated from the longitudinal thermal dispersivity using an empirical ratio. Thus, I wonder how you came to those values in your model.

For running your simulations, I highly recommend to switch to OGS6. As far as I know, OGS5 is no longer updated and there is a much higher chance that someone who came across your post is familiar with OGS6. FYI, you could refer to the benchmarks of HT problem:


benchmark duocumentation:
https://www.opengeosys.org/docs/benchmarks/hydro-thermal/constant-viscosity/
and input file documentation:
https://doxygen.opengeosys.org/ogs_file_param__ProjectFile.html

Hope it helps!

7

Appreciate your feedbacks and advice. Actually, my model is based on a given SEAWAT-based model(given parameter value). In that model, the dispersion package considers three-directions dispersion ( indeed, the empirical ration based on the longitudinal dispersion is applying there). I’ll try to switch to OGS6 to simulate my model. Thanks!