What is unit of bulk density?

The HP1 code incorporates modules simulating
(1) transient water flow in variably-saturated media,
(2) transport of multiple components, and
(3) mixed equilibrium/kinetic geochemical reactions.
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SCHan
Posts: 20
Joined: Sat Apr 14, 2018 2:58 pm
Location: Korea

What is unit of bulk density?

Post by SCHan » Sun Aug 09, 2020 7:59 pm

Hello, Hydrus users.

I know that many users already posted discussions on the units in Hydrus.
However, I cannot find adequate answers.
(And I already checked a related help file, i.e. "Other Topics" - "Units in HYDRUS".)

As I am using HP1, the mass unit which can be defined in the "Solute Transport - General Information" window is fixed as mol.
When I see the examples for HP1, the unit of mass for bulk (soil) density (which can be defined in the "Solute Transport - Transport Parameters" window) is fixed as g.
And I confirmed that a unit of length for bulk density was changed according to the unit that I selected in the "Geometry Information" window.

Am I right that the default unit of mass for the bulk density in HP1 is a gram (g)?
And the unit of mass for the bulk density is editable in the HP1 interface?

Thank you in advance for your help.

diederik
Posts: 62
Joined: Fri Mar 10, 2006 7:57 am
Location: Belgium

Re: What is unit of bulk density?

Post by diederik » Wed Aug 19, 2020 5:10 pm

Dear,

the variable bulk density defined in the HYDRUS Graphical user interface is not used in /transferred to HP1. The bulk density defined in the HYDRUS graphical user interface for adsorption calculations. This is not needed in HP1, there you use the phreeqc keywords exchange or surface to specify sorption processes. In these keywords, the sorption capacity is defined per dm3 bulk soil.

You can define bulk density in the HP1 input file with any dimension and use them in the calculations as long at the end you have the correct units for HP1 / Phreeqc input.

There is also a script function bulkdensity that takes the value defined in the HYDRUS GUI as it is, i.e. with the (current) units defined in HYDRUS GUI

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