[Sedullo]

I am running a case to simulate the natural convection boundary layer flow from a vertical plate using buoyantBoussinesqPimpleFoam.
Now the BC for alphat are set like this:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      alphat;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -1 0 0 0 0];

internalField   uniform 0;

boundaryField
{

    inlet
    {
        type calculated;
        value uniform 0;
    }

    outlet
    {
        type calculated;
        value uniform 0;
    }


    atmosphere
    {
        type calculated;
        value uniform 0;
    }

    hotWall
    {
        type            alphatJayatillekeWallFunction;
        Prt             0.85;
        value           $internalField;
    }



    #includeEtc "caseDicts/setConstraintTypes"
}

But it does not give any result that make sense, I cannot observe the boundary layer flow and I am quite sure that the problem is in this setting.
How would you set this?