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Running blockMesh​

  • Run blockMesh command in test case directory:
    # cd $FOAM_RUN /pitzDaily
    # blockMesh
  • Writes on the screen:
    /*---------------------------------------------------------------------------*\
    | =========                 |                                                 |
    | \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
    |  \\    /   O peration     | Version:  dev                                   |
    |   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
    |    \\/     M anipulation  |                                                 |
    \*---------------------------------------------------------------------------*/
    Build  : dev-e2ccbbbb
    Exec   : blockMesh
    Date   : Jun 16 2017
    Time   : 12:00:00
    Host   : $HOSTNAME
    PID    : $$
    Case   : $FOAM_RUN/pitzDaily
    nProcs : 1
    sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
    fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 10)
    allowSystemOperations : Allowing user-supplied system call operations
    
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
    Create time
    
    Creating block mesh from
        "$FOAM_RUN/pitzDaily/system/blockMeshDict"
    Creating block edges
    No non-planar block faces defined
    Creating topology blocks
    Creating topology patches
    
    Creating block mesh topology
    
    Check topology
    
    	Basic statistics
    		Number of internal faces : 5
    		Number of boundary faces : 20
    		Number of defined boundary faces : 20
    		Number of undefined boundary faces : 0
    	Checking patch -> block consistency
    
    Creating block offsets
    Creating merge list .
    
    Creating polyMesh from blockMesh
    Creating patches
    Creating cells
    Creating points with scale 0.001
        Block 0 cell size :
            i : 0.00158284 .. 0.000791418
            j : 0.000318841 .. 0.000420268
            k : 0.001 .. 0.001
    
        Block 1 cell size :
            i : 0.000528387 .. 0.00211355
            j : 0.00112889 .. 0.000360188
            k : 0.001 .. 0.001
    
        Block 2 cell size :
            i : 0.000528387 .. 0.00211355
            j : 0.000318841 .. 0.000420268
            k : 0.001 .. 0.001
    
        Block 3 cell size :
            i : 0.0020578 .. 0.00514451
            j : 0.000940741 .. 0.000940741
            k : 0.001 .. 0.001
    
        Block 4 cell size :
            i : 0.0020466 .. 0.00511651
            j : 0.00112889 .. 0.000257962
            k : 0.001 .. 0.001
    
    
    There are no merge patch pairs edges
    
    Writing polyMesh
    ----------------
    Mesh Information
    ----------------
      boundingBox: (-0.0206 -0.0254 -0.0005) (0.29 0.0254 0.0005)
      nPoints: 25012
      nCells: 12225
      nFaces: 49180
      nInternalFaces: 24170
    ----------------
    Patches
    ----------------
      patch 0 (start: 24170 size: 30) name: inlet
      patch 1 (start: 24200 size: 57) name: outlet
      patch 2 (start: 24257 size: 223) name: upperWall
      patch 3 (start: 24480 size: 250) name: lowerWall
      patch 4 (start: 24730 size: 24450) name: frontAndBack
    
    End
    

  • Command checkMesh checks the mesh and writes mesh information:
    # checkMesh

     

  • Screen output:
    /*---------------------------------------------------------------------------*\
    | =========                 |                                                 |
    | \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
    |  \\    /   O peration     | Version:  dev                                   |
    |   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
    |    \\/     M anipulation  |                                                 |
    \*---------------------------------------------------------------------------*/
    Build  : dev-e2ccbbbb
    Exec   : checkMesh
    Date   : Jun 16 2017
    Time   : 12:00:00
    Host   : $HOSTNAME
    PID    : $$
    Case   : $FOAM_RUN/pitzDaily
    nProcs : 1
    sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
    fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 10)
    allowSystemOperations : Allowing user-supplied system call operations
    
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
    Create time
    
    Create polyMesh for time = 0
    
    Time = 0
    
    Mesh stats
        points:           25012
        internal points:  0
        faces:            49180
        internal faces:   24170
        cells:            12225
        faces per cell:   6
        boundary patches: 5
        point zones:      0
        face zones:       0
        cell zones:       0
    
    Overall number of cells of each type:
        hexahedra:     12225
        prisms:        0
        wedges:        0
        pyramids:      0
        tet wedges:    0
        tetrahedra:    0
        polyhedra:     0
    
    Checking topology...
        Boundary definition OK.
        Cell to face addressing OK.
        Point usage OK.
        Upper triangular ordering OK.
        Face vertices OK.
        Number of regions: 1 (OK).
    
    Checking patch topology for multiply connected surfaces...
        Patch               Faces    Points   Surface topology                  
        inlet               30       62       ok (non-closed singly connected)  
        outlet              57       116      ok (non-closed singly connected)  
        upperWall           223      448      ok (non-closed singly connected)  
        lowerWall           250      502      ok (non-closed singly connected)  
        frontAndBack        24450    25012    ok (non-closed singly connected)  
    
    Checking geometry...
        Overall domain bounding box (-0.0206 -0.0254 -0.0005) (0.29 0.0254 0.0005)
        Mesh has 2 geometric (non-empty/wedge) directions (1 1 0)
        Mesh has 2 solution (non-empty) directions (1 1 0)
        All edges aligned with or perpendicular to non-empty directions.
        Boundary openness (-1.74458e-19 3.10465e-18 2.11178e-15) OK.
        Max cell openness = 2.21044e-16 OK.
        Max aspect ratio = 8.1407 OK.
        Minimum face area = 1.68589e-07. Maximum face area = 5.14451e-06.  Face area magnitudes OK.
        Min volume = 1.6902e-10. Max volume = 3.83579e-09.  Total volume = 1.4516e-05.  Cell volumes OK.
        Mesh non-orthogonality Max: 5.95045 average: 1.63034
        Non-orthogonality check OK.
        Face pyramids OK.
        Max skewness = 0.260575 OK.
        Coupled point location match (average 0) OK.
    
    Mesh OK.
    
    End

Previous: Fan Efficiency Up: Formulas for the Efficiency Next: Propeller Efficiency
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Wind Turbine Efficiency

Wind turbine efficiency 59 is given by formula

img135

where 60 is the power of the turbine, 61 is the maximal theoretical power given by Betz’s law, 62 is torque of the rotor and 63 is angular velocity of the rotor, 64 is density of air, 65 is area covered by the rotor and 66 is the velocity at inlet.