Fluid Fluid Coupling

Official adapters and tutorials
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2

Hi all,

I would like to add some additional info with regards to my queries above. In order to allow for the velocity and pressure from each domain to transfer to each other, I realised that it is necessary to set up two more variables, velocity2 and pressure2 into the adapter. This is done so as to write the velocity and pressure into the buffer while receiving velocity2 and pressure2 from another buffer, which is obtained from the right domain inlet. I have set up the preciceDict such that the Left domain:

interfaces
{
  Interface1
  {
    mesh              Fluid1-Mesh;
    patches           (outlet);

    readData
    (
      Pressure2
      Velocity2
    );

    writeData
    (
      Velocity
      Pressure
    );
  };
};

and on the right domain:

interfaces
{
  Interface1
  {
    mesh              Fluid2-Mesh;
    patches           (inlet);

    readData
    (
      Velocity
      Pressure
    );

    writeData
    (
      Pressure2
      Velocity2
    );
  };
};

I was able to get the simulation running but it was giving some error as follows:

---[precice]  relative convergence measure: relative two-norm diff of data "Pressure2" = inf, limit = 1.00e-06, normalization = 0.00e+00, conv = true

---[precice]  relative convergence measure: relative two-norm diff of data "Velocity" = 9.90e+01, limit = 1.00e-06, normalization = 2.24e-02, conv = false

---[precice] WARNING: The coupling residual equals almost zero. There is maybe something wrong in your adapter. Maybe you always write the same data or you call advance without providing new data first or you do not use available read data. Or you just converge much further than actually necessary.

---[precice] ERROR: Attempting to add a zero vector to the quasi-Newton V matrix. This means that the residuals in two consecutive iterations are identical. If a relative convergence limit was selected, consider increasing the convergence threshold.

Please advise how to resolve this. I have attached the precise-config.xml file here.

precice-config.xml (2.9 KB)

Thank you