Reply To: Could not addVelocityBoundary

[wf_guoyl]

Referring to case “cylinder2d”, the adjustment is as follows:

previous code:

 // create inflow
  origin = { 0, 0 };
  extend = { conversionLength, ly0-conversionLength };
  olb::IndicatorCuboid2D<SimType> inflow( extend, origin );
  superGeometry.rename( materialFluid, materialInflow, inflow ); 

  // create outflow
  origin = { lx0-conversionLength, 0 };
  extend = { conversionLength, ly0-conversionLength };
  olb::IndicatorCuboid2D<SimType> outflow( extend, origin);
  superGeometry.rename( materialFluid, materialOutflow, outflow);

the adjusted code — version 1.0

// create inflow
  origin = { -conversionLength, 0 };
  extend = { conversionLength, ly0-conversionLength };
  olb::IndicatorCuboid2D<SimType> inflow( extend, origin );
  superGeometry.rename( materialFluid, materialInflow, inflow ); 

  // create outflow
  origin = { lx0-conversionLength, 0 };
  extend = { 2*conversionLength, ly0-conversionLength };
  olb::IndicatorCuboid2D<SimType> outflow( extend, origin);
  superGeometry.rename( materialFluid, materialOutflow, outflow);

Error messages disappears.

the adjusted code — version 2.0

// create inflow
  origin = { -conversionLength, 0 };
  extend = { 2*conversionLength, ly0-conversionLength };
  olb::IndicatorCuboid2D<SimType> inflow( extend, origin );
  superGeometry.rename( materialFluid, materialInflow, inflow ); 

  // create outflow
  origin = { lx0-conversionLength, 0 };
  extend = { 2*conversionLength, ly0-conversionLength };
  olb::IndicatorCuboid2D<SimType> outflow( extend, origin);
  superGeometry.rename( materialFluid, materialOutflow, outflow);

Error message appears.

But I compared the cloud images of the three programs, it looks like these three have the same result. And this result feels like a velocity boundary condition has been applied in the left inlet.

So my problems are:
1.This error “Could not addVelocityBoundary (2,3) …… (2,69)” is generally related to which situation, why can the first version solve this problem.

2.When we define geometry, why do we have a little extra region on the left and right?

I’d appreciate it if anyone could answer. If I don’t give a clear description, I can send the program to your email. Thank you very much!