Search found 10 matches

by litlux
Tue Nov 12, 2019 12:42 am
Forum: Hydrus 1D
Topic: Capillary rise model
Replies: 1
Views: 1199

Capillary rise model

Hello everyone, I hope you all are having great time! I have one question regarding capillary rise model in HYDRUS 1D. Currently, I am working on soil column experiment. At first stage of the experiment, I set up the groundwater level constant for the soil column to allow the water rise up along the...
by litlux
Tue Oct 29, 2019 12:18 am
Forum: Hydrus 1D
Topic: Non-unique inversed model result
Replies: 2
Views: 1005

Re: Non-unique inversed model result

Dear Sir,

Thank you so much for your quick response.

I will definitely read those.

Best regards

Tho Tran
by litlux
Mon Oct 28, 2019 7:57 am
Forum: Hydrus 1D
Topic: Non-unique inversed model result
Replies: 2
Views: 1005

Non-unique inversed model result

Dear all, Hope everyone is doing great. I have one question regarding to non-unique result from inversed model. I am running inversed model in HYDRUS 1-D to find some key hydraulic parameters of soil column. I have fixed values of theta-r, theta-s,... The values of Ks, n and alpha are fitted. But if...
by litlux
Fri Oct 04, 2019 4:18 am
Forum: Hydrus 1D
Topic: Inverse model in HYDRUS - Water Content Profile
Replies: 4
Views: 1120

Re: Inverse model in HYDRUS - Water Content Profile

Dear Sir,

Thank you so much for your reply. That would help a lot. I agree that it is because the boundary condition we set up and precipitation rate is smaller than Ks value.

Again, thank you.

Best regards

Tho Tran
by litlux
Wed Oct 02, 2019 4:39 am
Forum: Hydrus 1D
Topic: Inverse model in HYDRUS - Water Content Profile
Replies: 4
Views: 1120

Re: Inverse model in HYDRUS - Water Content Profile

Dear Sir, Thank you for your reply. we have a loamy sand vertical soil column height of 66cm. We set the "groundwater level" is constant and simulated rainfall event with 1cm/hr precipitation. We assumed there is no evaporation. The boundary condition I set in HYDRUS was + Upper boundary condition: ...
by litlux
Wed Oct 02, 2019 12:28 am
Forum: Hydrus 1D
Topic: Inverse model in HYDRUS - Water Content Profile
Replies: 4
Views: 1120

Inverse model in HYDRUS - Water Content Profile

Dear, I am working on inverse model HYDRUS 1-D. We conducted an wetting experiment in vertical soil column and measure water content at different positions at the soil column until the certain time that we think it was almost saturated. I applied that data set to inverse model in HYDRUS 1D. My data ...
by litlux
Mon Sep 30, 2019 6:12 am
Forum: Hydrus 1D
Topic: Water flow parameters in HYDRUS
Replies: 1
Views: 719

Water flow parameters in HYDRUS

Dear all In the "Water Flow Parameters" in HYDRUS (as shown in the attached picture), the l parameter defined in HELP section of HYDRUS is Tortuosity parameter in the conductivity function. I wonder is that the same as pore connectivity parameter from MvG equation and is fixed as 0.5. Thank you so m...
by litlux
Wed Aug 14, 2019 1:11 am
Forum: Hydrus 1D
Topic: Inverse Model Input
Replies: 1
Views: 680

Inverse Model Input

Hi all, Hope you are all doing great. I have one question regarding to input for the inverse model. For the position column, for type 0, it is stated that "the code for specified boundary". Am I right that upper boundary will be 1 and bottom boundary will be 2. Also, for type 1, 2,4, position is the...
by litlux
Mon Jul 15, 2019 12:48 am
Forum: Hydrus 1D
Topic: Numerical errors in HYDRUS
Replies: 2
Views: 571

Re: Numerical errors in HYDRUS

This would indicate that the parameters are not identifiable. See the following article on the issue: Šimůnek, J., and J. W. Hopmans, Parameter Optimization and Nonlinear Fitting, In: Methods of Soil Analysis, Part 4, Physical Methods, Chapter 1.7, Eds. J. H. Dane and G. C. Topp, Third edition, SSS...
by litlux
Thu Jul 04, 2019 7:04 am
Forum: Hydrus 1D
Topic: Numerical errors in HYDRUS
Replies: 2
Views: 571

Numerical errors in HYDRUS

Hi. I am sorry for taking your time. My question seems stupid but. I am running an inverse model of unsaturated soil column with height of 45cm with the rainfall rate of 5.1cm/hr I input the values of moisture content at 3 observation points running time from 0.065h to 164 hour. Every time I change ...