Hi,

I'm trying to simulate a case where water is pumped from below sea level into an open tank/lake higher in the terrain. See figure below:



I'm trying to simulate this in Modelica (see below), but when I set the height difference in the pipe != 0 it does not simulate because of initial conditions (see error message just below). For reference, the pipe is set to not to allow reverse flow.

The following assertion has been violated during initialization at time 0.000000
til_LV1.flowModel.m_flows[1] > (-til_LV1.flowModel.m_flow_small)
Reversing flow occurs even though allowFlowReversal is false
simulation terminated by an assertion at initialization
Simulation process failed. Exited with code -1.



Are there any good way of simulating this setup in Modelica such that I don't get any reverse flow in the simulation?

Hi, This is my first post on this forum. Please forgive me if I post this sub-forum is not the correct location for this post.

I'm also very new to Modelica and OpenModelica and this report might also be due to my lack of understanding of Modelica and how to use it.

In one of my first applications I tried to simulate flow between two tanks though pipes and bends. Here, I stumbled upon a compilation issue when using the Modelica.Fluid.Fittings.Bends.CurvedBends model.

In the definition of the CurvedBend it defines the geometry parameter:

parameter Modelica.Fluid.Fittings.BaseClasses.Bends.CurvedBend.Geometry geometry

This geometry parameter is sent to Modelica.Fluid.Dissipation.PressureLoss.Bend.dp_curvedOverall_MFLOW, but the dp_curvedOverall_MFLOW function expects a parameter of type Modelica.Fluid.Dissipation.PressureLoss.Bend.dp_curvedOverall_IN_con (not Geometry).

This resulted in a crash while compiling the model. When I duplicated the CurvedBends model and replaced the geometry parameter above with:

parameter Modelica.Fluid.Dissipation.PressureLoss.Bend.dp_curvedOverall_IN_con geometry

The simulation worked and the results look reasonable.

This makes me believe that there is an inconsistency in the CurvedBends library in the Modelica package. However, if someone with more detailed knowledge of Modelica could give their input to this issue I would be grateful.

Best regards,
bluefjord