Search found 6079 matches

by Jirka
Thu Jul 25, 2024 7:31 am
Forum: HYDRUS (commercial version 1D,2D,3D)
Topic: Lowest moisture content
Replies: 1
Views: 27

Re: Lowest moisture content

The stress response function (the Feddes model) is a function that depends on pressure heads, not water contents. I would see what the water content for the wilting point pressure head is. You cannot get much lower water contents in your soil profile. Then I would see what the pressure head is for t...
by Jirka
Mon Jul 22, 2024 2:51 pm
Forum: HYDRUS (commercial version 1D,2D,3D)
Topic: drywell
Replies: 3
Views: 148

Re: drywell

As I have described in my previous email, if your initial condition is in pressure heads, then the initial water content will change whenever you change the soil hydraulic parameters (which is obviously done during the inverse modeling; you optimize, and thus allow to change, parameters alpha, n, an...
by Jirka
Mon Jul 22, 2024 6:58 am
Forum: HYDRUS (commercial version 1D,2D,3D)
Topic: Possibility of applying two sets of atm boundary conditions
Replies: 3
Views: 99

Re: Possibility of applying two sets of atm boundary conditions

You should use potential fluxes at the input. The code will calculate actual fluxes, using the hCritA and hCritS values (for a time-variable flux BC treated as an atmospheric BC). J.
by Jirka
Sat Jul 20, 2024 5:31 pm
Forum: HYDRUS (commercial version 1D,2D,3D)
Topic: drywell
Replies: 3
Views: 148

Re: drywell

If you want to keep the same initial water content conditions, while optimizing soil hydraulic parameters, you need to specify the initial conditions in terms of the water content. If your initial conditions are given in terms of the pressure head, whenever you change the soil hydraulic parameters (...
by Jirka
Thu Jul 18, 2024 8:20 am
Forum: HYDRUS (commercial version 1D,2D,3D)
Topic: Possibility of applying two sets of atm boundary conditions
Replies: 3
Views: 99

Re: Possibility of applying two sets of atm boundary conditions

On the right sidebar, there is a command "Boundary Condition Options" when boundary conditions are selected. On the first tab of the "Boundary Conditions Options," you can choose the option "Treat Time-Variable Flux BC as the Atmospheric BC." Instead of separate “Prec” and “Evap”, you need to enter ...
by Jirka
Sun Jul 07, 2024 12:45 pm
Forum: HYDRUS (commercial version 1D,2D,3D)
Topic: Can the WETLAND module be used for surface flow constructed wetlands
Replies: 6
Views: 287

Re: Can the WETLAND module be used for surface flow constructed wetlands

I do not feel like giving such an advice without carrying out a formal sensitivity analysis. J.
by Jirka
Thu Jul 04, 2024 6:54 pm
Forum: HYDRUS (commercial version 1D,2D,3D)
Topic: Can the WETLAND module be used for surface flow constructed wetlands
Replies: 6
Views: 287

Re: Can the WETLAND module be used for surface flow constructed wetlands

You clearly have some numerical instabilities in your project. Increase dispersivities (to 5 and 1 cm; to reduce the Peclet number), and you will likely get a stable solution. I’m not sure whether you can have alpha equal to zero. I have certainly never tested something like that. J.
by Jirka
Thu Jul 04, 2024 2:57 pm
Forum: HYDRUS (commercial version 1D,2D,3D)
Topic: Concentration at interface between subgrade and aquifer is higher than initial concentration on the ground surface
Replies: 1
Views: 139

Re: Concentration at interface between subgrade and aquifer is higher than initial concentration on the ground surface

Your problem is completely unrelated to the PFAS module. Note that you have huge mass balance errors already in water flow. You cannot get good results for solute transport, if you have problems with water flow. Your discretizations and iteration criterion cannot handle water flow, i.e., minimal flu...
by Jirka
Thu Jul 04, 2024 7:16 am
Forum: HYDRUS (commercial version 1D,2D,3D)
Topic: Modelling particle transport of car tire rubber particles using HYDRUS 1D
Replies: 9
Views: 339

Re: Modelling particle transport of car tire rubber particles using HYDRUS 1D

Based on your description, the particles are initially in the soil column, and they should therefore be introduced via initial conditions, and not via boundary conditions. It certainly makes no sense to use “volatile BC”, which is intended for volatile solutes, such as fumigants, carbon dioxide, oxy...
by Jirka
Wed Jul 03, 2024 8:09 am
Forum: HYDRUS (commercial version 1D,2D,3D)
Topic: Modelling particle transport of car tire rubber particles using HYDRUS 1D
Replies: 9
Views: 339

Re: Modelling particle transport of car tire rubber particles using HYDRUS 1D

Your questions: 1. Yes. 2. Two Kinetic Sites Model (particle transport). 3. There is plenty of guidance on the HYDRUS website on how to do this. See, for example: https://www.pc-progress.com/en/Default.aspx?h1d-lib-bacteria https://www.pc-progress.com/en/Default.aspx?h1d-lib-nanotubes and many refer...
by Jirka
Tue Jul 02, 2024 7:31 am
Forum: HYDRUS (commercial version 1D,2D,3D)
Topic: Modelling particle transport of car tire rubber particles using HYDRUS 1D
Replies: 9
Views: 339

Re: Modelling particle transport of car tire rubber particles using HYDRUS 1D

The next two weeks, I’m on vacation, traveling in Europe, and I will not have time to answer questions in the discussion forum. J.
by Jirka
Sat Jun 29, 2024 12:45 pm
Forum: Hydrus 1D (old free version)
Topic: Bottom flux
Replies: 1
Views: 203

Re: Bottom flux

It depends on the bottom BC. If you have a free drainage BC, then it should not be larger than Ks (since only the gravitational component of the total flux is active). If you have a pressure head BC, then it depends on the pressure heads in the profile, since you will have both gravitational and pre...
by Jirka
Fri Jun 28, 2024 6:31 pm
Forum: Hydrus 1D (old free version)
Topic: Flowrate
Replies: 5
Views: 226

Re: Flowrate

I think you should really review some basic soil physics. I have nothing more to add. J.
by Jirka
Fri Jun 28, 2024 6:30 pm
Forum: Hydrus 1D (old free version)
Topic: Solute concentration on day 1
Replies: 6
Views: 358

Re: Solute concentration on day 1

I think you should really review some basic soil physics. I have nothing more to add. J.