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Hi there,
I am wondering if "transient transport" can be run separately from a flow model run. In another word, to run a transient flow first, then save the simulation results of the end of the flow model run, and then run a transient transport on top of this "fixed" flow regime. I noticed there are three options for running a "flow and mass transport" model in FEFLOW, i.e. (1)steady flow/steady transport; (2) steady flow/transient transport; and (3) transient flow/transient transport. So, there are two options available for transient transport, i.e. options (2) and (3). I tried to use option (3) transient flow/transient transport to simulate; however, it took too much time to run. So, I am wondering if there is a way I can use the end results of a flow model run (transient), and run transient transport only on top of this simulated flow regime in stead of using option (2)- steady flow/transient transport. I remember Visual Modflow allows you to run flow and transport separately.

Thank you very much in advance!

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The hydraulic heads simulated look similar. The purpose of the modeling is not to estimate how much groundwater will flow into the pit once it is excavated. It is just used as a boundary condtion and see how it is going to affect the groundwater flow regime of the interested area.

thanks
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Hi,
A 3-dimensional flow model was created to simulate the groundwater flow regime due to open pit mining. The mined-out materials in the model were represented by assigning a low hydraulic conductivity (e.g. K=1X10-8 m/s). Two types of boundary conditions (i.e. "Seepage Nodes" and "Fluid-Transfer BC") were tried separately to mimic the pit excavation. (1) For "Seepage Nodes", they were assigned along the pit wall as well as the bottom of the pit excavation. (2) For "Fluid-Transfer BC", they were assigned along the pit wall only with a very high rate of "Transfer-Out". The same convergence critera were used for two separate transient runs. The model run with "Seepage Nodes" was very slow; and the model run with "Fluid-Transfer BC" was fast. So, I am wondering is it a right approach to use ""Fluid-Transfer BC" to simulate open pit mine or what may cause the model run with "Seepage Nodes" so slow? Your help is really appreciated!

Thanks!
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i think i figured it out. the value of 'snap distance' under the '1D linear interpolation' caused the problem. reduced 'snap distance' value to make sure only two river elevation values at point A and point B would be used for interpolation (i.e. excluding any existing constant-head values that were previously assigned along the river but outside the river segment A-B).

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hello,
i was using '1D linear interpolation' to generate constant-head boundary conditions along a river (FeFlow Classic). after river elevations at start point A and B were assigned, a*.shp (or *.lin) was used to join and the method of '1D linear interpolation' was used to generate the values for those nodes along the river between A and B. i checked the interpolated values after interpolation and found at some nodes the interpolated values were actually greater than the values at either A or B. in another word, the interpolated river elevations were 'mounded' somewhere between A and B. i was wondering what may cause this problem. were those node elevations (i.e. river bed topography) considered during the interpolation? your help is greatly appreciated!

thanks in advance

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forgot to mention that the vertical discretization in the interested area (i.e. drains or pit excavation) is approximately 1 m thick. in another word, the ratio (RWD/Vertical Layer Thickness) = 0.1.

thanks
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hello, 
a 3-D model was built to eatimate groundwater seepage rates flowing into a excavation pit through time. in order to make the model converge easily, the residual water depth (RWD) was increased (e.g. from the default value 0.001001 m to 0.1 m). after the simulation was completed, i tried to separate the 'extra' flux that was resulted from the increased RWD (0.1 m), by using budget analysis. i have seen some previous discussion regarding 'how to spearate this extra flux'; however, i do not know how to separate it either in Feflow Classic or Standard. your help is really appreciated!

thanks
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Thanks Peter!

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hello, does anyone know how to show isovalues along with isolines (e.g., hydraulic heads) in FEFLOW 6.0 standard?

thank you!
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Hi Peter - Thank you very much for your explanation!

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