• USF Fortran File: Buoyancy.f90
• USF Name: SeaPressure and SeaSpring
• Required Input Variable(s): None

The aim of these user functions is to apply the water hydrostatic pressure induced by the ocean at the base and at the front of floating ice mass.

The first user function (SeaPressure) is simply used to apply the hydrostatic water pressure for a given sea level (-rho_w. g . (Hsl - S - b.Ns.dt), where b is the normal basal melt/accretion rate.

The second user function (SeaSpring) evaluate the viscous spring (rho_w.g.Ns.dt) induced by any shift of the free surface from the hydrostatic equilibrium (should vanish for a steady-state geometry).

The required keywords in the SIF file for these user functions are:

!! melt/accretion under ice-shelf
Body Force 3
  DyBottom Accumulation = Real -1.0e0
End

Material 1
  ...
  Sea level = Real 0.0
End

!! vertical front (air and sea contact)
Boundary Condition 2
  Name = "front"
  Target Boundaries = 2

  Flow Force BC = Logical True
  External Pressure = Variable Coordinate 3
     Real Procedure "./Buoyancy" "SeaPressure"

  Compute Sea Pressure = Logical True
End

!! Bottom BC (Sea contact)
Boundary Condition 1
  Name = "bottom"
  Target Boundaries = 5
  Body Id = 3

  Normal-Tangential Velocity = Logical True
  Flow Force BC = Logical True
  External Pressure = Variable Coordinate 3
   Real Procedure "./Buoyancy" "SeaPressure"

  Slip Coefficient 1 = Variable Coordinate 3
    Real Procedure "./Buoyancy" "SeaSpring"

  Compute Sea Pressure = Logical True
  Compute Sea Spring = Logical True
End

An example of the usage of the user function SeaPressure can be found in the Tête Rousse application.