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Strange Block Mesh results

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Old   September 5, 2008, 05:05
Default Hi to evrybody! I'm trying to
  #1
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Ivan Flaminio Cozza
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Hi to evrybody!
I'm trying to simulate a 2D supersonic nozzle internal flow with sonicFoam, and the mesh is done with blockMesh.
I obtained no errors from checkMesh, but when I toke a look on it I found strange results from blockMesh, in particular some few cells are "oblique", while the others are allmost perpendicular to the nozzle wall. Moreover, when I try to refine the mesh, those oblique cells began self-intersecting, destroing the mesh.
The blockMeshDict is:

convertToMeters 1;

vertices
(
(-10 0 0) //0
(-3.45 0 0 ) //1
(-3.45 0.56418958 0) //2
(-10 0.56418958 0) //3
(-10 0 1) //4
(-3.45 0 1) //5
(-3.45 0.56418958 1)//6
(-10 0.56418958 1) //7
(0 0 0) //8
(0 0.3282429590 0) //9
(0 0 1) //10
(0 0.3282429590 1) //11
(3.55 0 0) //12
(3.55 0.413274 0) //13
(3.55 0 1) //14
(3.55 0.413274 1) //15
(10 0 0) //16
(10 0.413274 0) //17
(10 0 1) //18
(10 0.413274 1) //19
);

blocks
(
hex (0 1 2 3 4 5 6 7) (100 40 1) simpleGrading (1 1 1)
hex (1 8 9 2 5 10 11 6) (100 40 1) simpleGrading (0.3 1 1)
hex (8 12 13 9 10 14 15 11) (100 40 1) simpleGrading (3 1 1)
hex (12 16 17 13 14 18 19 15) (100 40 1) simpleGrading (1 1 1)
);

edges
(
simpleSpline 2 9 ((-3.4 0.5641895835 0)(-3.35 0.5641895835 0)(-3.3 0.5641895834 0)(-3.25 0.5641895833 0)(-3.2 0.5641895830 0)(-3.15 0.5641895826 0)(-3.1 0.5641895818 0)(-3.05 0.5641895804 0)(-3 0.5641895780 0)(-2.95 0.5641895737 0)(-2.9 0.5641895662 0)(-2.85 0.5641895534 0)(-2.8 0.5641895316 0)(-2.75 0.5641894950 0)(-2.7 0.5641894339 0)(-2.65 0.5641893331 0)(-2.6 0.5641891683 0)(-2.55 0.5641889019 0)(-2.5 0.5641884751 0)(-2.45 0.5641877984 0)(-2.4 0.5641867361 0)(-2.35 0.5641850852 0)(-2.3 0.5641825452 0)(-2.25 0.5641786766 0)(-2.2 0.5641728434 0)(-2.15 0.5641641366 0)(-2.1 0.5641512718 0)(-2.05 0.5641324556 0)(-2 0.5641052134 0)(-1.95 0.5640661730 0)(-1.9 0.5640107945 0)(-1.85 0.5639330422 0)(-1.8 0.5638249938 0)(-1.75 0.5636763840 0)(-1.7 0.5634740868 0)(-1.65 0.5632015420 0)(-1.6 0.5628381434 0)(-1.55 0.5623586092 0)(-1.5 0.5617323671 0)(-1.45 0.5609229953 0)(-1.4 0.5598877670 0)(-1.35 0.5585773570 0)(-1.3 0.5569357698 0)(-1.25 0.5549005550 0)(-1.2 0.5524033701 0)(-1.15 0.5493709486 0)(-1.1 0.5457265206 0)(-1.05 0.5413917216 0)(-1 0.5362890097 0)(-0.95 0.5303445956 0)(-0.9 0.5234918756 0)(-0.85 0.5156753410 0)(-0.8 0.5068549276 0)(-0.75 0.4970107562 0)(-0.7 0.4861482104 0)(-0.65 0.4743032841 0)(-0.6 0.4615481158 0)(-0.55 0.4479965870 0)(-0.5 0.4338097895 0)(-0.45 0.4192010227 0)(-0.4 0.4044397382 0)(-0.35 0.3898534625 0)(-0.3 0.3758261786 0)(-0.25 0.3627910203 0)(-0.2 0.3512146616 0)(-0.15 0.3415710272 0)(-0.1 0.3343036401 0)(-0.05 0.3297795792 0))
simpleSpline 6 11 ((-3.4 0.5641895835 1)(-3.35 0.5641895835 1)(-3.3 0.5641895834 1)(-3.25 0.5641895833 1)(-3.2 0.5641895830 1)(-3.15 0.5641895826 1)(-3.1 0.5641895818 1)(-3.05 0.5641895804 1)(-3 0.5641895780 1)(-2.95 0.5641895737 1)(-2.9 0.5641895662 1)(-2.85 0.5641895534 1)(-2.8 0.5641895316 1)(-2.75 0.5641894950 1)(-2.7 0.5641894339 1)(-2.65 0.5641893331 1)(-2.6 0.5641891683 1)(-2.55 0.5641889019 1)(-2.5 0.56418847511 1)(-2.45 0.5641877984 1)(-2.4 0.5641867361 1)(-2.35 0.5641850852 1)(-2.3 0.5641825452 1)(-2.25 0.5641786766 1)(-2.2 0.5641728434 1)(-2.15 0.5641641366 1)(-2.1 0.5641512718 1)(-2.05 0.5641324556 1)(-2 0.5641052134 1)(-1.95 0.5640661730 1)(-1.9 0.5640107945 1)(-1.85 0.5639330422 1)(-1.8 0.5638249938 1)(-1.75 0.5636763840 1)(-1.7 0.5634740868 1)(-1.65 0.5632015420 1)(-1.6 0.5628381434 1)(-1.55 0.5623586092 1)(-1.5 0.5617323671 1)(-1.45 0.5609229953 1)(-1.4 0.5598877670 1)(-1.35 0.5585773570 1)(-1.3 0.5569357698 1)(-1.25 0.5549005550 1)(-1.2 0.5524033701 1)(-1.15 0.5493709486 1)(-1.1 0.5457265206 1)(-1.05 0.5413917216 1)(-1 0.5362890097 1)(-0.95 0.5303445956 1)(-0.9 0.5234918756 1)(-0.85 0.5156753410 1)(-0.8 0.5068549276 1)(-0.75 0.4970107562 1)(-0.7 0.4861482104 1)(-0.65 0.4743032841 1)(-0.6 0.4615481158 1)(-0.55 0.4479965870 1)(-0.5 0.4338097895 1)(-0.45 0.4192010227 1)(-0.4 0.4044397382 1)(-0.35 0.3898534625 1)(-0.3 0.3758261786 1)(-0.25 0.3627910203 1)(-0.2 0.3512146616 1)(-0.15 0.3415710272 1)(-0.1 0.3343036401 1)(-0.05 0.3297795792 1))
simpleSpline 9 13 ((0.05 0.3287038432 0)(0.1 0.3300694627 0)(0.15 0.3322900376 0)(0.2 0.3352868057 0)(0.25 0.3389576923 0)(0.3 0.3431841428 0)(0.35 0.3478383237 0)(0.4 0.3527900008 0)(0.45 0.3579125817 0)(0.5 0.3630880209 0)(0.55 0.3682104702 0)(0.6 0.3731887005 0)(0.65 0.3779474100 0)(0.7 0.3824275823 0)(0.75 0.3865860760 0)(0.8 0.3903946228 0)(0.85 0.3938383975 0)(0.9 0.3969143083 0)(0.95 0.3996291311 0)(1 0.4019975956 0)(1.05 0.4040405108 0)(1.1 0.4057830000 0)(1.15 0.4072528979 0)(1.2 0.4084793465 0)(1.25 0.4094916119 0)(1.3 0.4103181307 0)(1.35 0.4109857817 0)(1.4 0.4115193694 0)(1.45 0.4119412993 0)(1.5 0.4122714179 0)(1.55 0.4125269883 0)(1.6 0.4127227724 0)(1.65 0.4128711899 0)(1.7 0.4129825292 0)(1.75 0.4130651866 0)(1.8 0.4131259159 0)(1.85 0.4131700743 0)(1.9 0.4132018533 0)(1.95 0.4132244888 0)(2 0.4132404468 0)(2.05 0.4132515826 0)(2.1 0.4132592742 0)(2.15 0.4132645331 0)(2.2 0.4132680923 0)(2.25 0.4132704768 0)(2.3 0.4132720582 0)(2.35 0.4132730965 0)(2.4 0.4132737714 0)(2.45 0.4132742057 0)(2.5 0.4132744823 0)(2.55 0.4132746568 0)(2.6 0.4132747657 0)(2.65 0.4132748330 0)(2.7 0.4132748742 0)(2.75 0.4132748992 0)(2.8 0.4132749142 0)(2.85 0.4132749231 0)(2.9 0.4132749283 0)(2.95 0.4132749314 0)(3 0.4132749332 0)(3.05 0.4132749342 0)(3.1 0.4132749347 0)(3.15 0.4132749350 0)(3.2 0.4132749352 0)(3.25 0.4132749353 0)(3.3 0.4132749354 0)(3.35 0.4132749354 0)(3.4 0.4132749354 0)(3.45 0.4132749354 0)(3.5 0.4132749354 0))
simpleSpline 11 15 ((0.05 0.3287038432 1)(0.1 0.3300694627 1)(0.15 0.3322900376 1)(0.2 0.3352868057 1)(0.25 0.3389576923 1)(0.3 0.3431841428 1)(0.35 0.3478383237 1)(0.4 0.3527900008 1)(0.45 0.3579125817 1)(0.5 0.3630880209 1)(0.55 0.3682104702 1)(0.6 0.3731887005 1)(0.65 0.3779474100 1)(0.7 0.3824275823 1)(0.75 0.3865860760 1)(0.8 0.3903946228 1)(0.85 0.3938383975 1)(0.9 0.3969143083 1)(0.95 0.3996291311 1)(1 0.4019975956 1)(1.05 0.4040405108 1)(1.1 0.4057830000 1)(1.15 0.4072528979 1)(1.2 0.4084793465 1)(1.25 0.4094916119 1)(1.3 0.4103181307 1)(1.35 0.4109857817 1)(1.4 0.4115193694 1)(1.45 0.4119412993 1)(1.5 0.4122714179 1)(1.55 0.4125269883 1)(1.6 0.4127227724 1)(1.65 0.4128711899 1)(1.7 0.4129825292 1)(1.75 0.4130651866 1)(1.8 0.4131259159 1)(1.85 0.4131700743 1)(1.9 0.4132018533 1)(1.95 0.4132244888 1)(2 0.4132404468 1)(2.05 0.4132515826 1)(2.1 0.4132592742 1)(2.15 0.4132645331 1)(2.2 0.4132680923 1)(2.25 0.4132704768 1)(2.3 0.4132720582 1)(2.35 0.4132730965 1)(2.4 0.4132737714 1)(2.45 0.4132742057 1)(2.5 0.4132744823 1)(2.55 0.4132746568 1)(2.6 0.4132747657 1)(2.65 0.4132748330 1)(2.7 0.4132748742 1)(2.75 0.4132748992 1)(2.8 0.4132749142 1)(2.85 0.4132749231 1)(2.9 0.4132749283 1)(2.95 0.4132749314 1)(3 0.4132749332 1)(3.05 0.4132749342 1)(3.1 0.4132749347 1)(3.15 0.4132749350 1)(3.2 0.4132749352 1)(3.25 0.4132749353 1)(3.3 0.4132749354 1)(3.35 0.4132749354 1)(3.4 0.4132749354 1)(3.45 0.4132749354 1)(3.5 0.4132749354 1))
);

patches
(
empty frontAndBack
(
(4 5 6 7)
(5 10 11 6)
(10 14 15 11)
(14 18 19 15)
(0 3 2 1)
(1 2 9 8)
(8 9 13 12)
(12 13 17 16)
)

patch inlet
(
(4 7 3 0)
)
patch outlet
(
(19 18 16 17)
)
symmetryPlane bottom
(
(1 5 4 0)
(8 10 5 1)
(12 14 10 8)
(16 18 14 12)
)
patch top
(
(6 2 3 7)
(11 9 2 6)
(15 13 9 11)
(19 17 13 15)
)
);

mergePatchPairs
(
);

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

Has anyone an idea on what's goin' on?
Thank you,
Ivan
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Old   December 4, 2008, 09:24
Default Yes. A bug in simpleSpline. St
  #2
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Wolfgang Heydlauff
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Yes. A bug in simpleSpline. Still in OF-1.5 Also don't use polySpline. But at your quality of control points you might use the polyLine command instead.
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