[Mass transport of point pollution sources by X1t]

Dear Jia ~

Thanks again for your assistance and teaching. The example is from a textbook about mass transport of solutes. You can see the attached file for the original question. Cl- 30mg/L is the value of analytical solution calculated by the formula. I want to get the value of numerical solution by GWB, then confirm the difference between these two method.

If I model a continuously leaking point source contamination for 1 year, the wave crest of solute don’t move in the resulting graph (X-position vs. Cl- in fluid (mg/l)) with time and distance. So I think it’s not continuously leaking for 1 year. The time for contaminant leaking should be very short, so we can see  the moving of solute slug with time and distance (like figure 11.11 in attached file). Thank you.

example.pdf

[Mass transport of point pollution sources by X1t]

On 1/24/2020 at 7:37 AM, Jia Wang said:

Hello Anita,

I took a quick look at your input file and here are a couple of suggestions to help you get started. 

 

It seems like you are trying to model a continuously leaking point source contamination for 1 year. However, I notice that in your Intervals pane, you are only setting a one day reaction interval for the 'contaminated' fluid to enter your system at the inlet and the remaining time flushing the system with dilute fluid. If the goal is to simulate a continuously leaking source of contamination at the inlet, then you should remove the second reaction interval from your simulation and allow for the contaminated fluid flow into the system for a full year. To quickly remove any reaction interval period in your Intervals pane, you can simply click to select it and then click the delete button. I deleted the reaction interval that set the inlet fluid as the dilute fluid (named 'fluid 2') and that allow the model to run to completion. 

 

For more information on setting boundary conditions and reaction intervals, please refer to section 2.10 and 2.9 in the Reactive Transport User's Guide. You might also be interested in looking at X1t examples listed in section 3.5. The input file corresponding to each example in section 3.5 is available in the GWB installation subdirectory 'Script'. 

 

Hope this helps,

 

Jia Wang

Dear Jia ~

   Thanks for your response. In this problem,  Cl pollutant  is instantaneous leaking to groundwater layer, then compute the Ccl-  at d=15m after 1y from the leaking point.  Therefore, I set two different fluids in Fluids pane and  two reaction interval in  Intervals pane. If I set one minute(or one second) reaction interval for the contaminated fluid to enter the system at the inlet and the remaining time flushing the system with dilute fluid, the program cat't run. It shows "residuals too large, 669-th interation, Newton failed at node 0, ............ , Abandoning simulation". What's wrong with this. How can I correct the setting so that the program can run normally?  Thank you. 

 

1D nonreact-6instant.x1t

[Mass transport of point pollution sources by X1t]

hi~

I'm just beginning to learn GWB. I am confused about the boundary condition setting of a single point source pollution for one-dimensional mass transport. Attached are the questions and the setting of X1t simulation parameters. Maybe I guess there are something wrong on the Intervals pane, so it can't be runing. But I don't know how to modify the setting. Could you please help me, thank you.

 

 

Question of non-reactive one-dimensional solute transport.pptx 1D nonreact-2.x1t