Carlos Andres Rivera Villarreyes Global Product Specialist - FEFLOW

Hi Siddarth, I would recommend you to take a look the FEFLOW Introduction Tutorial: https://www.mikepoweredbydhi.com/-/media/shared%20content/mike%20by%20dhi/flyers%20and%20pdf/product-documentation/feflow-introductory-tutorial.pdf FEFLOW works only with projected coordinates. You need X and Y in meters (or ft). The task is not FEFLOW related. You will find tons of materials and tutorial in internet about coordinate transformation. Best regards Carlos Rivera

Hi Max, Not surely whether I understood entirely. Is the problem occuring in a FEFLOW model being coupled to TRNSYS? Or are you using also in the "uncoupled" problem? Please note that the plug-in is not anymore supported by DHI. Cheers Carlos

Hi Salman, You may want to take a look on our free self-paced course "FEFLOW – Getting started with FEFLOW Python Interface", where exactly this task is explained through a working example. Registration link is below: https://www.theacademybydhi.com/course-sessions/feflow---getting-started-with-feflow-python-interface-11600061-104 Cheers Carlos Rivera

Hi Guanyu, The plug-in should come with some help. If not, I copy below the text. Cheers Carlos ###### OPENLOOP 1.5 FUNCTIONALITY HEAT TRANSPORT The OpenLoop plugin is designed for applying a time-varying temperature differential between groups of abstraction and injection boreholes for open-loop geothermal systems. It is capable of handling more than one group of extraction/injection pairs simultaneously, using separate temperature differentials for each group. Within each group, extraction as well as injection can take place in an unlimited number of mesh nodes. The module can also deal with systems where extraction and injection nodes are inverted during the simulation time. Furthermore, the application of the module for any group can start at any time during the simulation run. Before that time, temperature conditions from the model setup are used for the infiltration bore(s). This might be useful for representing observation data (real injection temperatures) in the first phase, while using calculated injection temperatures for the prediction phase. MASS TRANSPORT The OpenLoop plug-in can also be used for applying a concentration differential in mg/l. The module support thermohaline (heat and mass transport) simulations and multi-species mass transport.. DATA PREPARATION 1. All time-varying temperature and concentration differentials are defined as time-varying power functions in FEFLOW. For each system of injection/extraction nodes and each process variable (temperature, each species concentration) a separate time-varying power function has to be prepared, even if differentials in different systems or for different chemical species are identical. 2. A nodal reference distribution with the name 'OpenLoop' is created to identify participating nodes for a temperature differential. For single-species mass transport, the distribution is called 'OpenLoop Mass', for multi-species transport 'OpenLoop Mass 1' for species 1, 'OpenLoop Mass 2' for species 2, etc..In these reference distributions, all nodes belonging to a specific group (injection and extraction nodes) are assigned a value equal to the number of the time-varying power function containing the corresponding temperature or concentration differential. All other nodes need to be given values less than or equal to 0 (default in FEFLOW is -99999 = nodata). Be careful with mesh refinement: In case of refining the mesh after assigning the power function number, the data interpolation will lead to a number of nodes with non-zero values around the wells, too. 3. A nodal reference distribution with the name 'OpenLoop AutoOn' may be created to postpone the automatic boundary condition setting / removal on certain nodes. All nodes with a later start should be assigned the start time [d] for automatic temperature calculation. All other nodes in the distribution shall have zero or negative values. This option can be useful for simulations whose first part is based on observation data for injection wells, while the second predictive part is to be run based on a temperature or concentration differential. SIMULATION RUN In each time step, the module will calculate the average abstraction temperature or concentration. The calculation is done separately for each group, and averaging is done based on the contribution to total energy or contaminant mass abstraction by pumping from each extraction node. The temperature or concentration differential derived from the time-varying power function associated to the group is added (+) to the average temperature/concentration, and the result is used to set a fixed temperature/concentration (1st kind) boundary condition at the injection nodes. The temperature/concentration boundary condition is adapted to the current extraction temperature/concentration and temperature/concentration differential before each time step of the simulation. A time-stepping control scheme integrated in the plug-in ensures that all time steps in the temperature differential functions are met exactly if the model is run based on automatic time stepping.

It will be helpful if you describe the parameter used and the workflow. In the attached image, you can see that FEFLOW recharge applied as In/outflow on top/bottom takes into consideration the area only. I believe you are using other parameter, applying an expression to the parameter, or other configuration, which could cause the unexpected values. In case you have very specific questions about your model, the technical support (mike.de@dhigroup.com) can take provide you detailed guidance. Best regards Carlos Rivera  

In the case of a 2D Discrete Feature Element (DFE), FEFLOW considers as thickness the dimension perpendicular to the plane. Best regards Carlos

Hola Cecilia, In general FEFLOW 7.0 is a very old version. Please be aware that Fully supported operating systems are Windows 7 Professional Service Pack 1 (64 bit), Windows 10 Pro (64 bit), Windows Server 2012 R2 Standard (64 bit) and Windows Server 2016 Standard (64 bit). The freezing behaivoir can be trigged by several issues, including the plug-in itself. I can only recommend you to work with the latest update of FEFLOW 7.0. Best regards Carlos Rivera

Hi Tomás,
With your explanation, it looks to me that the expression does not spatially constraint the operation. A mathematical expression is applied to the FEFLOW's parameter and to all the mesh elements (automatically). So, you need to reformulate the express, eg. to apply the In/Outflow on top/bottom only to specific areas. A tip: Expressions works also with Elemental User Distributions. You can use them for creating the constraints.
Please follow-up with our technical support at mike.de@dhigroup.com for details on the workflows.
Cheers
Carlos Rivera

Hi Emilia,<br> The definition is available in the White Paper Vol. IV page 49. Here is the link:<br> https://www.mikepoweredbydhi.com/-/media/shared%20content/mike%20by%20dhi/flyers%20and%20pdf/product-documentation/feflow%20white%20papers%20vol,-d-,5.pdf<br> <br> If you have any question about the applicability in a FEFLOW project, I would recommend you to contact the FEFLOW technical support at mike.de@dhigroup.com<br> <br> Best regards<br> Carlos

Hi Josue,<br> <br> Without looking the file, my first guess is that the observation points are just directly in the frozen soil. FEFLOW piFreeze reduces significantly the hydraulic conductivity and &quot;close&quot; the porosity in order to mimic the freezing conditions. For example, if you have low K values and together a boundary node at the same location, which could cause outflow, the situation may be an uncontrolled decrease in head.<br> <br> Please get in touch with MIKE Support (mike.de@dhigroup.com) for further discussion.<br> <br> Best regards<br> Carlos