[Victor3]

I’m trying to model the water hammer effect using sonicLiquidFoam. I’ve changed the tutorial example to have an inlet with constant pressure (1 bar) on top of the tank. The pipe out from the tank has been lengthen to 0.3m.

On the end of the outlet pipe (nozzle) I change the speed from 1m/s to 0 m/s in 0.0001s.

I am expecting it to run “normally” up to the velocity change then show a pressure wave in the pipe. Any ideas how to do this? Guessing I’m doing the inlet wrong?

P:

  dimensions      [1 -1 -2 0 0 0 0];
   
  internalField   uniform 100000; // 1 bar
   
  boundaryField
  {
      outerWall
      {
          type            zeroGradient;
      }
   
      axis
      {
          type            symmetryPlane;
      }
   
      nozzle
      {
          type            zeroGradient;
      }
   
      back
      {
          type            empty;
      }
   
      front
      {
          type            empty;
      }
   
      inlet
      {
          type            fixedValue;
          value           uniform 100000; // 1 bar
      }
  }

U:

  dimensions      [0 1 -1 0 0 0 0];
   
  internalField   uniform (0 0 0);
   
  boundaryField
  {
      outerWall
      {
          type            noSlip;
      }
   
      axis
      {
          type            symmetryPlane;
      }
   
      nozzle
      {
         type        uniformFixedValue;
         uniformValue    table
          (
          (0 (1 0 0))
           (0.0001 (1 0 0))
          (0.0002 (0 0 0))
          );
      }
   
      back
      {
          type            empty;
      }
   
      front
      {
          type            empty;
      }
   
      inlet
      {
          type            zeroGradient;
      }
  }

BlockMesh:

  scale   0.1;
   
  vertices
  (
      (0 0 -0.1)
      (1 0 -0.1)
      (0 0.5 -0.1)
      (1 0.5 -0.1)
      (4 0.5 -0.1)
      (0 0.6 -0.1)
      (1 0.6 -0.1)
      (4 0.6 -0.1)
      (0 3 -0.1)
      (1 3 -0.1)
      (0 0 0.1)
      (1 0 0.1)
      (0 0.5 0.1)
      (1 0.5 0.1)
      (4 0.5 0.1)
      (0 0.6 0.1)
      (1 0.6 0.1)
      (4 0.6 0.1)
      (0 3 0.1)
      (1 3 0.1)
  );
   
  blocks
  (
      hex (0 1 3 2 10 11 13 12) (30 20 1) simpleGrading (1 1 1) // top part of tank
      hex (2 3 6 5 12 13 16 15) (30 5 1) simpleGrading (1 1 1) // inside tank downstream inlet
      hex (3 4 7 6 13 14 17 16) (200 5 1) simpleGrading (1 1 1) // inlet
      hex (5 6 9 8 15 16 19 18) (30 20 1) simpleGrading (1 1 1) // lower part of tank
  );
   
  // Fine mesh
  // blocks
  // (
  //     hex (0 1 3 2 10 11 13 12) (120 80 1) simpleGrading (1 1 1) // top part of tank
  //     hex (2 3 6 5 12 13 16 15) (120 20 1) simpleGrading (1 1 1) // inside tank downstream inlet
  //     hex (3 4 7 6 13 14 17 16) (800 20 1) simpleGrading (1 1 1) // inlet
  //     hex (5 6 9 8 15 16 19 18) (120 380 1) simpleGrading (1 1 1) // lower part of tank
  // );
   
  edges
  (
  );
   
  boundary
  (
      inlet
      {
          type patch;
          faces
          (
              (9 8 18 19)
          );
      }
      outerWall
      {
          type wall;
          faces
          (
              (0 1 11 10)
              (1 3 13 11)
              (3 4 14 13)
              (7 6 16 17)
              (6 9 19 16)
        //      (9 8 18 19)
          );
      }
      axis
      {
          type symmetryPlane;
          faces
          (
              (0 10 12 2)
              (2 12 15 5)
              (5 15 18 8)
          );
      }
      nozzle
      {
          type patch;
          faces
          (
              (4 7 17 14)
          );
      }
      back
      {
          type empty;
          faces
          (
              (0 2 3 1)
              (2 5 6 3)
              (3 6 7 4)
              (5 8 9 6)
          );
      }
      front
      {
          type empty;
          faces
          (
              (10 11 13 12)
              (12 13 16 15)
              (13 14 17 16)
              (15 16 19 18)
          );
      }
  );
   
  mergePatchPairs
  (
  );