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Mirage12 July 11, 2013 03:22

icoFoam- unphysical results
 
1 Attachment(s)
Hello world :)

I wanted to simulate a incompressible flow around the cylinder (Re 100), but unlikely after running the simulation (8.236 sec) the solver crashed and results look not correct.


in the attachement please find a screen-shot of the case (time 8.232 sec).

time-step 0.0001 s

BC for U :

Code:

internalField  uniform (1 0 0);

boundaryField
{
    inlet
    {
        type            freestream;
        freestreamValue uniform (1 0 0);
    }

    outlet
    {
        type            freestream;
        freestreamValue uniform (1 0 0);
    }

    fixedWalls
    {
        type            fixedValue;
        value          uniform (0 0 0);
    }

    frontAndBack
    {
        type            empty;
    }
}

why are the results not correct ?
Do you know, how to stabilize icoFoam ?

akidess July 11, 2013 04:33

http://www.cfd-online.com/Forums/ope...-get-help.html

Mirage12 July 12, 2013 04:52

2 Attachment(s)
Thanks akidess,

Here is my blockMesh :

Code:

// The OpenFOAM Project // File: blockMeshDict
  /*
  -------------------------------------------------------------------------------
  =========        | dictionary
  \\      /        |
    \\    /          | Name:  blockMeshDict
    \\  /          | Family: FoamX configuration file
      \\/            |
      F ield        | OpenFOAM version: 2.3
      O peration    | Product of Nabla Ltd.
      A and          |
      M anipulation  | author: Amine Abdelmoula
  -------------------------------------------------------------------------------
  */
  // FoamX Case Dictionary.
 
  FoamFile
  {
      version        2.0;
      format          ascii;
 
      root            "";
      case            "";
      instance        "";
      local          "";
 
      class          dictionary;
      object          blockMeshDict;
  }
 
  // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 convertToMeters 1;
 
  vertices
  (
      (0.5 0 -0.5)//0----------------------------1. HAELFTE VON DEM BODEN
      (1 0 -0.5)//1
      (30 0 -0.5)//2
      (30 0.707107 -0.5)//3
      (0.707107 0.707107 -0.5)//4
      (0.353553 0.353553 -0.5)//5
      (30 8 -0.5)//6
      (0.707107 8 -0.5)//7
      (0 8 -0.5)//8
      (0 1 -0.5)//9
      (0 0.5 -0.5)//10
      (-0.5 0 -0.5)//11
      (-1 0 -0.5)//12
      (-6 0 -0.5)//13
      (-6 0.707107 -0.5)//14
      (-0.707107 0.707107 -0.5)//15
      (-0.353553 0.353553 -0.5)//16
      (-6 8 -0.5)//17
      (-0.707107 8 -0.5)//18----------------------------------------------------
      (0.5 0 0.5)//19----------------------------1. HAELFTE VON DEM DECKEL
      (1 0 0.5)//20
      (30 0 0.5)//21
      (30 0.707107 0.5)//22
      (0.707107 0.707107 0.5)//23
      (0.353553 0.353553 0.5)//24
      (30 8 0.5)//25
      (0.707107 8 0.5)//26
      (0 8 0.5)//27
      (0 1 0.5)//28
      (0 0.5 0.5)//29
      (-0.5 0 0.5)//30
      (-1 0 0.5)//31
      (-6 0 0.5)//32
      (-6 0.707107 0.5)//33
      (-0.707107 0.707107 0.5)//34
      (-0.353553 0.353553 0.5)//35
      (-6 8 0.5)//36
      (-0.707107 8 0.5)//37----------------------------------------------------
      (30 -0.707107 -0.5)//38----------------------------2.HAELFTE VON DEM BODEN
      (0.707107 -0.707107 -0.5)//39
      (0.353553 -0.353553 -0.5)//40
      (30 -8 -0.5)//41
      (0.707107 -8 -0.5)//42
      (0 -8 -0.5)//43
      (0 -1 -0.5)//44
      (0 -0.5 -0.5)//45
      (-6 -0.707107 -0.5)//46
      (-0.707107 -0.707107 -0.5)//47
      (-0.353553 -0.353553 -0.5)//48   
      (-6 -8 -0.5)//49
      (-0.707107 -8 -0.5)//50----------------------------------------------------
      (30 -0.707107 0.5)//51----------------------------2.HAELFTE VON DEM DECKEL
      (0.707107 -0.707107 0.5)//52
      (0.353553 -0.353553 0.5)//53
      (30 -8 0.5)//54
      (0.707107 -8 0.5)//55
      (0 -8 0.5)//56
      (0 -1 0.5)//57
      (0 -0.5 0.5)//58
      (-6 -0.707107 0.5)//59
      (-0.707107 -0.707107 0.5)//60
      (-0.353553 -0.353553 0.5)//61   
      (-6 -8 0.5)//62
      (-0.707107 -8 0.5)//63--------------
     
  );
 
  blocks
  (
      hex (5 4 9 10 24 23 28 29) (20 20 1) simpleGrading (1 1 1) // 0--------------------BLOECKE IM OBEREN BEREICH
      hex (0 1 4 5 19 20 23 24) (20 20 1) simpleGrading (1 1 1)// 1
      hex (1 2 3 4 20 21 22 23) (70 20 1) simpleGrading (60 1 1)//2
      hex (4 3 6 7 23 22 25 26) (70 100 1) simpleGrading (60 4 1)// 3
      hex (9 4 7 8 28 23 26 27) (20 100 1) simpleGrading (1 4 1)//4
      hex (15 16 10 9 34 35 29 28) (20 20 1) simpleGrading (1 1 1)//5
      hex (12 11 16 15 31 30 35 34) (20 20 1) simpleGrading (1 1 1)//6
      hex (13 12 15 14 32 31 34 33) (70 20 1) simpleGrading (0.1 1 1)//7
      hex (14 15 18 17 33 34 37 36) (70 100 1) simpleGrading (0.1 4 1)//8
      hex (15 9 8 18 34 28 27 37) (20 100 1) simpleGrading (1 4 1)//9--------------------BLOECKE IM UNTEREN BEREICH
      hex (44 39 40 45 57 52 53 58) (20 20 1) simpleGrading (1 1 1)//10
      hex (40 39 1 0 53 52 20 19) (20 20 1) simpleGrading (1 1 1)//11
      hex (39 38 2 1 52 51 21 20) (70 20  1) simpleGrading (60 1 1)//12
      hex (42 41 38 39 55 54 51 52) (70 100 1) simpleGrading (60 0.2 1)//13
      hex (43 42 39 44 56 55 52 57) (20 100 1) simpleGrading (1 0.2 1)//14
      hex (47 44 45 48 60 57 58 61) (20 20 1) simpleGrading (1 1 1)//15
      hex (47 48 11 12 60 61 30 31) (20 20 1) simpleGrading (1 1 1)//16
      hex (46 47 12 13 59 60 31 32) (70 20 1) simpleGrading (0.1 1 1)//17
      hex (49 50 47 46 62 63 60 59) (70 100 1) simpleGrading (0.1 0.2 1)//18
      hex (50 43 44 47 63 56 57 60) (20 100 1) simpleGrading (1 0.2 1)//19

  );
 
  edges
  (
      arc 0 5 (0.469846 0.17101 -0.5)
      arc 5 10 (0.17101 0.469846 -0.5)
      arc 4 1 (0.939693 0.34202 -0.5)
      arc 9 4 (0.34202 0.939693 -0.5)
      arc 19 24 (0.469846 0.17101 0.5)
      arc 24 29 (0.17101 0.469846 0.5)
      arc 20 23 (0.939693 0.34202 0.5)
      arc 23 28 (0.34202 0.939693 0.5)
      arc 16 11 (-0.469846 0.17101 -0.5)
      arc 10 16 (-0.17101 0.469846 -0.5)
      arc 12 15 (-0.939693 0.34202 -0.5)
      arc 15 9 (-0.34202 0.939693 -0.5)
      arc 30 35 (-0.469846 0.17101 0.5)
      arc 35 29 (-0.17101 0.469846 0.5)
      arc 31 34 (-0.939693 0.34202 0.5)
      arc 34 28 (-0.34202 0.939693 0.5)
      arc 40 0 (0.469846 0.17101 -0.5)//---
      arc 45 40 (0.17101 0.469846 -0.5)
      arc 1 39 (0.939693 -0.34202 -0.5)
      arc 39 44 (0.34202 -0.939693 -0.5)
      arc 19 53 (0.469846 -0.17101 0.5)
      arc 53 58 (0.17101 -0.469846 0.5)
      arc 20 52 (0.939693 -0.34202 0.5)
      arc 52 57 (0.34202 -0.939693 0.5)
      arc 11 48 (-0.469846 -0.17101 -0.5)
      arc 48 45 (-0.17101 -0.469846 -0.5)
      arc 47 12 (-0.939693 -0.34202 -0.5)
      arc 44 47 (-0.34202 -0.939693 -0.5)
      arc 30 61 (-0.469846 -0.17101 0.5)
      arc 61 58 (-0.17101 -0.469846 0.5)
      arc 31 60 (-0.939693 -0.34202 0.5)
      arc 60 57 (-0.34202 -0.939693 0.5)

  );
 
boundary
(

 inlet
    {
        type patch;
        faces
        (
         
    (17 14 33 36)
    (14 13 32 33)
    (13 46 59 32)
    (46 49 62 59)     
  );
    }
    outlet
    {
        type patch;
        faces
        (
            (3 6 25 22)
            (2 3 22 21)
            (38 2 21 51)
        (41 38 51 54)   
           
     
             
        );
    }
 
    fixedWalls
    {
        type wall;
        faces
        (

          (18 17 36 37)
          (8 18 37 27)
          (7 8 27 26)
          (6 7 26 25)
          (49 50 63 62)
          (50 43 56 63)
      (43 42 55 56)
          (42 41 54 55)
      (11 16 35 30)
          (16 10 29 35)
      (10 5 24 29)
          (5 0 19 24)
      (11 48 61 30)
          (48 45 58 61)
      (45 40 53 58)
          (40 0 19 53)
     
          );
    }     

    frontAndBack
    {
        type empty;
        faces
        ( 
          (2 1 4 3)
      (3 4 7 6)
          (4 9 8 7)
          (9 15 18 8)
          (15 14 17 18)
          (12 13 14 15)
          (47 46 13 12)
          (50 49 46 47)
          (43 50 47 44)
          (42 43 44 39)
          (41 42 39 38)
          (38 39 1 2)
          (1 0 5 4)
          (4 5 10 9)
          (9 10 16 15)
          (15 16 11 12)
          (12 11 48 47)
              (47 48 45 44)
        (45 40 39 44)
        (40 0 1 39) //---------------------------
          (20 21 22 23)
          (23 22 25 26)
          (28 23 26 27)
          (34 28 27 37)
          (33 34 37 36)
          (32 31 34 33)
          (59 60 31 32)
          (62 63 60 59)
          (63 56 57 60)
          (56 55 52 57)
          (55 54 51 52)
          (52 51 21 20)
          (19 20 23 24)
          (29 24 23 28)
          (35 29 28 34)
          (31 30 35 34)
          (60 61 30 31)
          (60 57 58 61)
          (57 52 53 58)
          (52 20 19 53)
         
     
        );
    }
);



mergePatchPairs
(
);

// ************************************************************************* //

Time step : dt=0.0001

i will run the case again and upload the output of OpenFOAM :)


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