modeling on soil water movement

A discussion forum for old Hydrus-2D & Meshgen. Happy Posting!
Download PDF document with all topics (February 8, 2008, 1.9MB):
http://www.pc-progress.com//Downloads/F ... on_H2D.pdf
Post Reply
baozhwen
Posts: 13
Joined: Wed Aug 18, 2010 7:42 am

modeling on soil water movement

Post by baozhwen » Wed Aug 18, 2010 7:43 am

<font face="Arial">Dear Hydrus Developers,
I am a freshman to Hydrus. Now I have studied the Hydrus-2D carefully. With my doubts, I feel difficult to establish my physical model for Hydrus-2D to solve my problem.
Now I want simulate the soil water movement under the point source such as surface and subsurface conditions with the water flux(known), can you guide me some suggestions on how to build the boundary conditions and on how to represent the point source?
Thanks in advance.
Bob
</font id="Arial">

Jirka
Posts: 4712
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Post by Jirka » Wed Aug 18, 2010 1:56 pm

You should follow the tutorial "Source" that you can find here at the HYDRUS website. You can also download examples "Drip" from our library of examples (http://www.pc-progress.com/en/Default.aspx?h3d-lib-drip).

Jirka

baozhwen
Posts: 13
Joined: Wed Aug 18, 2010 7:42 am

Post by baozhwen » Mon Aug 23, 2010 8:08 am

Dear sir, when we want to research on different applied water rates, I believe, we may get different results according to the Hydrus-2D's simulation. However, I feel difficult to understand how the irrigating rate can be used in the model. So please give me some advice. Thanks in advance.

Jirka
Posts: 4712
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Post by Jirka » Mon Aug 23, 2010 8:29 am

I do not see how I can help you more than I already did in my first response. J.

baozhwen
Posts: 13
Joined: Wed Aug 18, 2010 7:42 am

Post by baozhwen » Mon Aug 23, 2010 1:14 pm

Yes, Jirka, thanks for your patience to guide me. Now I am quite familiar with the basic features of Hydrus-2D. Through carefull consideration, I find my problem is the initial boundary conditions of water content. The initial boundary condtions of water content in my research have four levels according to the depth. I designed the changes linearly according to the depth. Unfortunately, the software didn't work. To ensure it's right, I change the initial condtion of water content into one level. It worked well. But that's not my demand. So, to four different changing trend of water content, I can't solve the problem, can you give some advice? Thanks,
Bob

Jirka
Posts: 4712
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Post by Jirka » Mon Aug 23, 2010 4:36 pm

The software allows you to specify the linear distribution of pressure head with depth. That makes sense since that represents a constant gradient with depth. Linear distribution of water content with depth is much less reasonable from the physical point of view, since that would represent a variable pressure head gradient with depth. You can obviously specify that also, but then you need to do it manually, depth by depth, and not automatically.

J.

Post Reply