Search found 5264 matches

by Jirka
Mon Jul 26, 2021 5:09 pm
Forum: Hydrus 1D
Topic: Temperature effects on reaction rate coefficients not working (?)
Replies: 1
Views: 9

Re: Temperature effects on reaction rate coefficients not working (?)

I’m pretty sure that this option is working as we have used it in a couple of projects. Take, for example, Test3 (Solute transport with nitrification chain), use the activation energy number of 50k for SinkWater1’ and SinkSolid1’, and see the graph of “Cumulative first order reaction”. It will be si...
by Jirka
Mon Jul 26, 2021 4:49 pm
Forum: HYDRUS (2D/3D)
Topic: Cum_Q.out & evaporation/transpiration
Replies: 2
Views: 12

Re: Cum_Q.out & evaporation/transpiration

1. Potential evapotranspiration is often estimated using the reference evapotranspiration multiplied by a crop coefficient. This value then needs to be divided into potential evaporation and potentially transpiration, which is usually done using LAI or SFC (Surface Cover Fraction). 2. CumQAP and Cum...
by Jirka
Thu Jul 22, 2021 4:40 pm
Forum: HYDRUS (2D/3D)
Topic: Concentration Unit
Replies: 2
Views: 24

Re: Concentration Unit

Please, see Section 4.1 of the user manual for the Wetland module, where we discuss the topic of units. Especially, “Table 4.1. Units of concentrations in the liquid and solid phases and of the bulk density.” Let me quote from the manual: “The HYDRUS user interface does not provide conversion of mas...
by Jirka
Wed Jul 21, 2021 2:07 pm
Forum: Hydrus 1D
Topic: Inverse solution not working
Replies: 1
Views: 24

Re: Inverse solution not working

When running the inverse problem for the first time, run it with 0 Max Number of Iterations (in the Inverse Solution dialog window). Then look at the graphical outputs and whether your inverse data are correctly interpreted (if you entered correct codes and positions). They should appear at appropri...
by Jirka
Tue Jul 20, 2021 3:25 pm
Forum: Hydrus 1D
Topic: No result after successful calculation
Replies: 8
Views: 1912

Re: No result after successful calculation

I think you should read some texts on Uniqueness, identifiability, stability, and ill-posedness of the inverse solution. We have written some texts on the topic (see below). You cannot expect to be able to fit parameters that do not affect the measured data. J. Šimůnek, J., and J. W. Hopmans, Parame...
by Jirka
Mon Jul 19, 2021 5:32 pm
Forum: Hydrus 1D
Topic: No result after successful calculation
Replies: 8
Views: 1912

Re: No result after successful calculation

The problem is badly defined. It’s impossible to estimate five soil hydraulic parameters from the solute BTC for a column with constant flux conditions. J.
by Jirka
Mon Jul 19, 2021 5:23 pm
Forum: Hydrus 2D (old version 1996 - 2005)
Topic: Subsurface drip irrigation
Replies: 3
Views: 61

Re: Subsurface drip irrigation

Amina, I have tried my best of explaining all this on the HYDRUS website (and in the article that I recommended) and do not know what else I can add to it. Note that we list on the Hydrus website over one hundred papers in which HYDRUS has been successfully used to simulate drip irrigation (and we s...
by Jirka
Sun Jul 18, 2021 9:33 pm
Forum: HYDRUS (2D/3D)
Topic: Fen wetland simulation
Replies: 5
Views: 157

Re: Fen wetland simulation

You seem to ignore all advice that we give on how to handle coarse materials exposed to the atmospheric BC or with root water uptake. J.
by Jirka
Sun Jul 18, 2021 9:20 pm
Forum: Hydrus 2D (old version 1996 - 2005)
Topic: Subsurface drip irrigation
Replies: 3
Views: 61

Re: Subsurface drip irrigation

It’s simple. First, you need to convert the real 3D case (experiment or reality) into a 2D (plane, or axisymmetrical domain) problem, and then you need to implement that into the model, i.e., to make sure that you get the right amount of water into the simulated transport domain (whether it is half-...
by Jirka
Wed Jul 14, 2021 7:43 pm
Forum: HYDRUS (2D/3D)
Topic: 3D infiltration well
Replies: 15
Views: 343

Re: 3D infiltration well

I just copied the program and the test example that I provided back to my PC and ran it without any problems. Perhaps, you should make the working directory permanent, otherwise, I do not know what I can suggest. I have started implementing this option into the next version of HYDRUS, which will com...
by Jirka
Tue Jul 13, 2021 10:23 pm
Forum: HYDRUS (2D/3D)
Topic: Constant Flux/Pressure on Semicircle Boundary
Replies: 5
Views: 100

Re: Constant Flux/Pressure on Semicircle Boundary

It’s not a rocket science. You have a real 3D problem with individual drippers. First, you need to convert it into a 2D (plane) problem, and then you need to implement that in the model. J.
by Jirka
Tue Jul 13, 2021 9:02 pm
Forum: HYDRUS (2D/3D)
Topic: Constant Flux/Pressure on Semicircle Boundary
Replies: 5
Views: 100

Re: Constant Flux/Pressure on Semicircle Boundary

Won’t you figure this out by yourself? Come on! J.
by Jirka
Tue Jul 13, 2021 7:38 pm
Forum: HYDRUS (2D/3D)
Topic: 3D infiltration well
Replies: 15
Views: 343

Re: 3D infiltration well

I do not have all the time in the world to spend with one Hydrus user (when we have thousands of them). You will need to take the hard road and figure out some things yourself and post only questions, which you really cannot figure out yourself. J.
by Jirka
Tue Jul 13, 2021 7:36 pm
Forum: HYDRUS (2D/3D)
Topic: Constant Flux/Pressure on Semicircle Boundary
Replies: 5
Views: 100

Re: Constant Flux/Pressure on Semicircle Boundary

What is important is to get the right amount of water into the transport domain (model). You should multiply your specified flux by the length of the boundary (where you apply the flux). The exact length of the boundary is given in the output file Boundary.out (at the beginning). You should also tak...
by Jirka
Tue Jul 13, 2021 7:33 pm
Forum: HYDRUS (2D/3D)
Topic: SDI characteristics function
Replies: 6
Views: 253

Re: SDI characteristics function

I do not recall; it’s 15 years. J.