[Getdp] trouble with Heat Equation

trophime christophe trophime at labs.polycnrs-gre.fr
Thu Jun 7 12:02:30 CEST 2001


Hi, I'm back with some stupid questions...

I am trying to set a transient Heat Equation
and I end up with some problems:

1/ which is the default orientation of the normal
on line (or surface)?

My initial formulation expect the normal to be exterior
is this right?

  FunctionSpace {
    { Name Hgrad_v_Th ; Type Form0 ;
      BasisFunction {
        // T = T  s   ,  for all nodes
        //      n  n
        { Name sn ; NameOfCoef tn ; Function BF_Node ;
          Support Region[ {Domain_Th, SurfaceConvection,
SurfaceHeatFlux} ] ; Entity NodesOf[ All ] ; }
      }
      Constraint {
        { NameOfCoef tn ; EntityType NodesOf ; 
          NameOfConstraint FixedTemperature ; }
      }
    }

    // Source heat (fully fixed space)
    { Name Hregion_qth_Heat_Axi ; Type Scalar ;
      BasisFunction {
        { Name sr ; NameOfCoef qthsr ; Function BF_Node ;
          Support DomainS_Th ; Entity NodesOf[ All ] ; }
      }
      Constraint {
        { NameOfCoef qthsr ; EntityType NodesOf ;
          NameOfConstraint SourceHeatDensity ; }
      }
    }

  }

  Formulation {
    { Name Heat_Axi ; Type FemEquation ;
      Quantity {
        { Name T ; Type Local ; NameOfSpace Hgrad_v_Th ; }
        { Name Qth ; Type Local ; NameOfSpace Hregion_qth_Heat_Axi ; }
      }
      Equation {
        Galerkin { [ k[] * Dof{d T} , {d T} ] ; In Domain_Th ; 
                   Jacobian VolAxi ; Integration GradGrad ; }
        Galerkin { [ -Dof{Qth} , {T} ]; In DomainS_Th ;
                   Jacobian VolAxi ; Integration GradGrad ; }
        Galerkin { [ -h[] * Dof{T} , {T} ]; In SurfaceConvection; 
	           Jacobian SurAxi ; Integration I1; }
        Galerkin { [ h[] * T_ambiant[] , {T} ]; In SurfaceConvection; 
	           Jacobian SurAxi ; Integration I1; }
        Galerkin { [ -Flux[] , {T} ]; In SurfaceHeatFlux; 
	           Jacobian SurAxi ; Integration I1; }
      }
    }

2/ how to set both initial and boundary conditions?
I have tried the following:

   { Name FixedTemperature; Type Assign;
      Case {
        { Region Region[{Domain_Th, SurfaceConvection,
SurfaceHeatFlux}]; Type Init; Value T_ref;}
        { Region BottomSurfaceInd1; Type Assign; Value T_Bottom;}
        { Region TopSurfaceInd1; Type Assign; Value T_Top;}
        { Region BottomSurfaceInd; Type Assign; Value T_Bottom;}
        { Region TopSurfaceInd; Type Assign; Value T_Top;}
       }
    }

But I get Neuman BC on the lines where I want to set a Dirichlet BC.



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