samsamia22

Thank you for the reply.

I just have one more question regarding the discrete features.
I modeled my fractures using the Manning approach and it works perfectly, however I am having trouble with the following:

I have 2 piezometers 2Km apart in my karst and they react to a change in hydraulic head at the same second.
i.e: I have a steady state condition. I apply a varying head condition on the uphil and simulate in transient mode. I want to see the propagation of my wave. I have no head loss in my karst (which I need) but the problem is that all the points in the karst change at the same time. There is no delay in that part of the model. Is there a way to create a delay in my karst according to the distance from HH BC (without creating head loss)???
Thank you

Hello,

I am modeling a flood wave across a large 3D model. The model is a square with 2500m sides.
My wave should affect the whole model equally, a rise of the water table of 3m then a decrease to the original level. So far, I used two different approaches:

1) I added on the bottom layer of my model an inflow and calibrated it to reproduce the wave (rise of 3m then decrease).

2) I simulated a wave on the uphill and calibrated it so I get the response of 3m at my observation well, but across the whole model the wave is not calibrated. I have a damping effect.

The problem with the first method is that it doesn't represent what is really happening on the site and I have vertical flow across the whole model.
The problem with the second is the damping effect.

Any ideas on how I can simulate this???

Thank you

Hello everyone,

I am modeling a 3D Karst system. I used the discrete features to define my karst: thickness = 0.1m and hydraulic conductivity = 0.1 m/s ( HH BC = 0m at the left side and HH BC= -5m on the right side). As a starting point I created only one layer of karst in the middle of my model just to test the results. As a first step I ran the model in steady state to establish the equilibrium, then I ran it in transient mode and I have increased the value of my hydraulic head BC at the left side from 0m to 10m using the time series option. I placed two observation points, one at the slice containing the Karst and one 10 m below it.

I was expecting that the HH at observation point in the karst would increase earlier than the one 10 m below. However, when I plotted the HH for the two piezometers I got the exact same curve for both.

My questions are:
1) How can I see the hydraulic head in the Karst only ?
2) Is it a better method to create an additional layer with the a high enough K rather than using the DF ?
3) The result of the observation point gives the HH in the karst or in the element?

Thank you

Sam

Hi,

I have a square 3D model with hydraulic head boundary conditions on the edges.
My hydraulic head BC is not constant along the edge, I have created a dat file that links the hydraulic head to each node by linking the node numbers to each other.
Now i want to run model in transient state. the value of the hydraulic head at each node has changed. My da file has now a column that points to the node number and 3 different columns that point to the hydraulic head at different time steps. Is it possible to link the change in hydraulic head for each node automatically, direclty from the dat file ? If yes, can you please show me how. (ie: I want to assign the value in each column to a time step, for all the nodes in my file).
Thank you

Hello,
I am building a 3D GW model using Feflow. The model has 2 different soil layers. The topography has a slope shape going from 300 m asl (above sea level) to 250 m asl. The first layer is 20 m thick and the second layer is parallel to the topography. When I create my model I have all the slices parallel. However, I want to insert a slice at 270 m asl of constant elevation (horizontal slice). If I do so, I will intercept the top slice and the bottom slice. I need that slice to model a foundation of constant elevation at 270 m asl. Is there a way to do that? Or should I divide my model into tiny slices and model the foundation as cutting through different slices?
Thank you
Sam

Hello everyone,

I have a 3D model with inactive elements representing an excavation. I was wondering if it was possible to make these elements invisible rather than change their color (for localisation purposes only) so I can see the different layers that were excavated.

Thank you

thank you peter. I am thinking of implementing a seepage face BC on the active/inactive element faces... would that work ???
( assuming that at these edges, water will still flow in my excavated area and I want to see of the water table with the excavation face).

Thank you

hello,

I have a 3D model with different layers. I want to model an excavation in the middle of my model. the area excavated is limited to the first layer and has a rectangular shape. if i select the necessary elements and dis-activate them (inactive elements) will feflow consider it as an excavated area or will it consider it as an impermeable area ?
Is there any other way to model an excavated area in feflow ?

Thank you
Sam

Hi everyone,
I am building a 3D model of a rectangular area of dimensions 2200m x 2500 m. I have a 0.8m thick wall inside the model that i created using supermesh lines. Every time I try to generate the mesh I get an error message. I am using the gridbuilder option. Does anyone have an idea how to create an appropriate mesh, where I have large elements on the sides and very fine elements in my wall.
PS: I need to have the nodes at the edge of the wall (for modeling purposes).
Thank you

Hi,
I am simulating a 3D river problem and I have pumping wells next to the river. To start I imposed my BC in the river and at the boundaries of the model. Before I start the pumping I want to run the model in steady state to spread the hydraulic heads across the whole model. After that I will create my pumping wells and I want to run the model in transient state. My question is: How can I use the previous results of the steady state as starting input parameters in the transient state?
I thought of running the model in steady state and extracting the results in a dat file, then I re-open the model (same BC) and I create a map of the hydraulic head results and link these results to "process variables, fluid flow, hydraulic heads" and then I run the simulation in transient state.
Is it a convenient way to tackle the problem or does Feflow re-impose these hydraulic head values at each simulation step?
Thank you
Sam