Search found 41 matches

by mahardie
Fri Sep 29, 2017 5:50 am
Forum: HYDRUS (2D/3D)
Topic: Inverse simulation from Disk permeameter
Replies: 0
Views: 2197

Inverse simulation from Disk permeameter

HI I am attempting to determine the van Genuchten parameter values of a soil crust by inverse simulation of infiltration from a mini-disk infiltrometer (small disk permeameter) for which i have infiltration at 6 supply potentials. Looking at the CRUST example supplied with HYDRUS I note the crust wa...
by mahardie
Fri Sep 22, 2017 2:34 am
Forum: HYDRUS (2D/3D)
Topic: Best measure of error for inverse solution
Replies: 1
Views: 1198

Best measure of error for inverse solution

Hi Im running a number of different options for inversely solving infiltration from a tension infiltrometer at 5 tension steps. My question is what is the best measure of fit or error to judge the best inverse solution. The options are, variance of the individual parameters, the r^2 fit, the correla...
by mahardie
Tue Jun 06, 2017 5:32 am
Forum: Hydrus 1D
Topic: Modelling Infiltration
Replies: 1
Views: 1735

Modelling Infiltration

Hi I am wondering if I can use hydrus to explore the effects of initial soil moisture content on the transition from early infiltration rate to steady state. In field studies infiltration decreases with time to a steady state infiltration rate. The difference in early and final infiltration rate dep...
by mahardie
Fri Aug 12, 2016 3:57 am
Forum: Hydrus 1D
Topic: Teaching material
Replies: 1
Views: 1903

Teaching material

Hi I lecture in soil physics at the University of Tasmania, Australia. I wish to include teaching HYDRUS in my soil physics course. I was wondering if there are any appropriate teaching resources, ie powerpoints, tutorials, examples that are available (other than the tutorials on the PC-Progress web...
by mahardie
Mon Aug 01, 2016 1:08 am
Forum: HYDRUS (2D/3D)
Topic: Surface Drip inflow volume.
Replies: 1
Views: 3568

Surface Drip inflow volume.

Hi again im simulating a surface drip. using 2d standard array, with dynamic wetting option, center node and var1 flux problem is converting from litres to cm (in 2d) It flowed at 2.4 Litres for an hour so my inflow through the nodes is 2400 cm^3 How do I make this a 2d value ie cm. to put in the Va...
by mahardie
Fri Nov 13, 2015 1:55 am
Forum: HYDRUS (2D/3D)
Topic: root solute Uptake.
Replies: 9
Views: 10713

Re: root solute Uptake.

Thanks again for helping I tried adjusting the h4 and hcritA Didn't seem to make much difference It crashes during larger rainfall events when the soil is quite wet Im using the durner model as it really fits my soil data well. Any other suggestions. Is it worth adjusting the time step controls and ...
by mahardie
Thu Nov 12, 2015 10:00 pm
Forum: HYDRUS (2D/3D)
Topic: root solute Uptake.
Replies: 9
Views: 10713

Re: root solute Uptake.

Hi J Ive tried a number of remeshing attempts Ive brought the solute error down from 14% to about 11 % many of the simulations crash with a warning ORTHOMIN terminates too many iterations, time step reduced The only way I seem to have to get around this is to drop the initial time step to 1 x 10-5, ...
by mahardie
Fri Nov 06, 2015 4:15 am
Forum: HYDRUS (2D/3D)
Topic: root solute Uptake.
Replies: 9
Views: 10713

Re: root solute Uptake.

thanks
ive sent the file by email

marcus
by mahardie
Fri Nov 06, 2015 1:14 am
Forum: HYDRUS (2D/3D)
Topic: root solute Uptake.
Replies: 9
Views: 10713

Re: root solute Uptake.

I still have problems. The original simulation had 1604 nodes, minimum time step of 1e-006, max time step of 0.2 which resulted in 14.78% error in concentration, 0.89 % error in water balance, calculation time of 16878 sec Balance indicates I had ATM N input 345, root uptake 415, deep drainage 41. S...
by mahardie
Tue Nov 03, 2015 11:21 pm
Forum: HYDRUS (2D/3D)
Topic: root solute Uptake.
Replies: 9
Views: 10713

root solute Uptake.

Hi, hope you can help Im running a 2D simulation of nitrate movement in an apple orchard. The simulation seems to indicate the tree is taking more N than I have applied. The cumulative fluxes are: atm solute flux is 345.16 mg/cm, the root solute uptake is 420 mg/cm, deep drainage is 43 mg/cm. The st...
by mahardie
Fri Feb 13, 2015 2:19 am
Forum: HYDRUS (2D/3D)
Topic: Understanding outputs
Replies: 1
Views: 2503

Understanding outputs

Hi again Couple of quick questions related to the output results screen Cumulative potential atmospheric flux - is the area of water applied to the surface accumulated on a daily basis (assuming daily input data)...so the average depth of water (rainfall) is the cumulative total atm flux divided by ...
by mahardie
Tue Feb 10, 2015 12:59 am
Forum: HYDRUS (2D/3D)
Topic: Calculation of solute flux
Replies: 3
Views: 3522

Re: Calculation of solute flux

Yes the water flow seems to solve well, and I get convergence
I tried to attach a word doc and a pdf.
What files can be attached to show you the problem
by mahardie
Mon Feb 09, 2015 10:27 pm
Forum: HYDRUS (2D/3D)
Topic: Calculation of solute flux
Replies: 3
Views: 3522

Calculation of solute flux

Im having trouble with solute flux into an atm boundary. On the edges of the boundary I get massive spikes in solute leading to large plumes in solute and massive error in the calculation of the solute mass balance in the order of 25-125 % my time step is 10-6, pulse duration is a day, same as my ti...
by mahardie
Thu Jul 31, 2014 7:09 am
Forum: HYDRUS (2D/3D)
Topic: Multiple atmospheric boundaries
Replies: 9
Views: 9670

Re: Multiple atmospheric boundaries

Ive just done another test It is only applying solute where I have a 3rd type pointer 3, in which a solute concentration is entered in the cValue1 column. in other words its looks like the dual transpiration version no longer associates the pointer values on the 3rd type nodes to the second and thir...
by mahardie
Thu Jul 31, 2014 6:49 am
Forum: HYDRUS (2D/3D)
Topic: Multiple atmospheric boundaries
Replies: 9
Views: 9670

Re: Multiple atmospheric boundaries

Im having trouble with solute application. The transpiration for each region appears to be working fine However the solute application is now about 2 orders of magnitude lower Im not sure what I have failed to do. In the crop mound (transpiration area 1 defigned by roots) i have a atm boundary to wh...