Hi Peter

thank's for your reply.

Indeed, the way you describe it is exactly how I realize the two solvers.

Just, for the background. In Czochralski growth we have melt and gas flow. This want to separate as for gas flow it is not useful to include crystal and crucible rotation but for melt it is important. For this reason a use two different Flow solvers with two different boundary conditions. (At the melt/gas interface it is Marangoni flow for melt but non-slip for gas).

However, solving the heat equation in the entire furnace I want to solve one heat equation. Thus I need one velocity field containing melt velocity and gas velocity.

As the problem is axi-symmetric the azimuthal velocity does not play any role and can be set to zero for the advection equation.

For melt convection I can define

- Code: Select all
`Solver 9`

Equation = "Navier-Stokes-Melt"

Procedure = "FlowSolve" "FlowSolver"

Stabilize = True

Variable = Flow Solution Melt [Velocitymelt:3 Pressuremelt:1]

!!! Update all exported variables

Update Exported Variables = Logical True

Exported Variable 1 = Flow Solution [Velocity:3 Pressure:1]

Exported Variable 2 = -dofs 3 Velocityout

where in the heat solver the advection term is set by

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` Solver 3`

Equation = Heat Equation

Procedure = "HeatSolve" "HeatSolver"

Variable = -dofs 1 Temperature

Temperature Convection Field = Flow Solution [Velocity:3 Pressure:1]

The velocities are set by a body force in the melt domain:

- Code: Select all
` Velocity 1 = Variable Velocitymelt 1`

Real MATC "tx"

Velocity 2 = Variable Velocitymelt 2

Real MATC "tx"

Velocity 3 = Real 0

Pressure = Variable Pressuremelt

Real MATC "tx"

The question is how to do the same for the gas velocity.

Same kind of Body Force in the gas domain does not work because for the same export variable a segmentation error occur.