Search found 4982 matches

by Jirka
Wed Jul 01, 2020 3:01 am
Forum: HP1 (HYDRUS-1D - PHREEQC)
Topic: Mass balance issue with 'surface layer' boundary
Replies: 4
Views: 236

Re: Mass balance issue with 'surface layer' boundary

You need to copy these files into the HYDRUS folder (where the HYDRUS software is installed). J.
by Jirka
Tue Jun 30, 2020 11:37 pm
Forum: HP1 (HYDRUS-1D - PHREEQC)
Topic: Mass balance issue with 'surface layer' boundary
Replies: 4
Views: 236

Re: Mass balance issue with 'surface layer' boundary

The code was not meant for conditions when the entire profile is fully saturated and simultaneous atmospheric and free drainage BCs. However, we can handle that as well. Try the attached updated code. J. sum(rTop)=137.48 cm (it's negative but to simplify I only keep the absolute values for all resul...
by Jirka
Sat Jun 27, 2020 10:06 pm
Forum: Hydrus 1D
Topic: Soil water evaporation
Replies: 5
Views: 403

Re: Soil water evaporation

As I wrote above, the surface node should be slightly unsaturated. When you have the VG model with an air entry value of -2 cm, i.e., the surface pressure head should be below -2 to make it unsaturated. hCritA: I do not have more to say in addition to what's written in the help. I would not change t...
by Jirka
Fri Jun 26, 2020 8:29 pm
Forum: HYDRUS (2D/3D)
Topic: Well as constant head
Replies: 9
Views: 1512

Re: Well as constant head

I'm pretty sure that "Pulse Duration" works OK if you use this option correct. Note the definition in the User Manual: " Pulse Duration: Time duration of the concentration pulse. Concentrations (flux or resident) along all boundaries, for which no time-variable boundary conditions are specified, are...
by Jirka
Thu Jun 25, 2020 6:52 pm
Forum: HYDRUS (2D/3D)
Topic: Well as constant head
Replies: 9
Views: 1512

Re: Well as constant head

What you say is not correct. The units for internal node recharge are [L2/T] (see the figure below) and [L3/T] in 2D and 3D, respectively. J.
NodalRecharge.png
NodalRecharge.png (18.53 KiB) Viewed 472 times
by Jirka
Thu Jun 25, 2020 6:44 pm
Forum: Hydrus 1D
Topic: Recharge estimation from pond
Replies: 1
Views: 172

Re: Recharge estimation from pond

Can you provide a schematic? J.
by Jirka
Wed Jun 24, 2020 2:26 pm
Forum: HYDRUS (2D/3D)
Topic: Well as constant head
Replies: 9
Views: 1512

Re: Well as constant head

Qp is the pumping rate (positive for removal of water, negative for adding water) ([L2 T–1] or [L3 T–1] for two-dimensional and axisymmetric systems, respectively). See Figure 2.7 in the technical manual or Fig. 1 in: Šimůnek, J., M. Šejna, and M. Th. van Genuchten, New Features of the Version 3 of ...
by Jirka
Fri Jun 19, 2020 8:20 pm
Forum: Hydrus 1D
Topic: Using HYDRUS-1D Upside down!
Replies: 1
Views: 212

Re: Using HYDRUS-1D Upside down!

1. Indeed, the decline from vertical axes is equal to 1, 0, -1 for vertical downward, horizontal, and vertical upward flow. It is the magnitude of gravity. You should be able to run in the inverse mode a project that has gravity=-1. 2. Evaporation is the solution of the surface energy balance equati...
by Jirka
Thu Jun 18, 2020 7:04 pm
Forum: Hydrus 1D
Topic: Solute concetration in drain discharge
Replies: 1
Views: 232

Re: Solute concetration in drain discharge

The standard HYDRUS module (but none of the specialized modules, such as HP1 or UnsatChem) has an option to choose if the drainage flux (to horizontal drains, qdrain) is applied at the bottom of the soil profile or vertically distributed along the saturated part of the soil profile. This is obviousl...
by Jirka
Wed Jun 17, 2020 2:28 pm
Forum: HP1 (HYDRUS-1D - PHREEQC)
Topic: Horizontal flow in Hydrus 1D
Replies: 1
Views: 207

Re: Horizontal flow in Hydrus 1D

Sure, we do not rotate the graph for horizontal flow and use the same ones as for vertical flow. You need to interpret the top in the graph as the left end, and the bottom as the right end. Similarly, top fluxes are the fluxes at the left side and the bottom fluxes at the right side. You can interpr...
by Jirka
Wed Jun 17, 2020 2:22 pm
Forum: HYDRUS (2D/3D)
Topic: water balance
Replies: 3
Views: 354

Re: water balance

You can do both. However, if you do that correctly, you need to get the same results as those reported by Hydrus. J.
by Jirka
Tue Jun 16, 2020 8:52 pm
Forum: HYDRUS (2D/3D)
Topic: Rapid increases in fluxes & high error
Replies: 3
Views: 272

Re: Rapid increases in fluxes & high error

The results correctly reflect the modeling set up. You have large sudden fluxes at the seepage face and time-variable boundaries, whenever you suddenly lower or raise the water table in the ditch. Since you are using the option "Seepage face BC when the specified nodal pressure head is negative", on...
by Jirka
Tue Jun 16, 2020 5:42 pm
Forum: Hydrus 1D
Topic: mass lumped finite element scheme
Replies: 1
Views: 215

Re: mass lumped finite element scheme

I suggest the following two publications. The first one you can download from https://www.pc-progress.com/en/Default.aspx?rien-van-genuchten: van Genuchten, M.Th., Numerical solutions of the one dimensional saturated unsaturated flow equation. Research Report No. 78 WR 9, Water Resources Program, De...
by Jirka
Mon Jun 15, 2020 8:32 pm
Forum: Hydrus 1D
Topic: Non-closure outside of GUI
Replies: 8
Views: 564

Re: Non-closure outside of GUI

I had no trouble running both projects. j.
by Jirka
Mon Jun 15, 2020 8:29 pm
Forum: HYDRUS (2D/3D)
Topic: Rapid increases in fluxes & high error
Replies: 3
Views: 272

Re: Rapid increases in fluxes & high error

I would need to see the project to be able to comment. J.