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### General Informations

• Solver Fortran File: `GetHydrostaticLoads.f90`
• Solver Name: `GetHydrostaticLoads`
• Required Output Variable(s): `Fw` (user defined DOFs=2 in 2D, 3 in 3D)
• Required Input Variable(s): `External Pressure`
• Optional Output Variable(s): None
• Optional Input Variable(s): None

### General Description

For a given boundary, this solver computes the equivalent nodal force induced by a pressure on the surface (read from the keyword `External Pressure`). The result is a force vector (Fx,Fy) in 2D and (Fx,Fy,Fz) in 3D.

### Known bugs

2018-12-15: Periodic boundary conditions fixed

2013-03-07: GetHydrostaticloads has an issue for periodic boundary conditions: the force is half what it should be on the periodic boundary whereas the residual account for the fact that the domain is periodic. TODO: fix this!

### SIF contents

```Solver 1
Equation = Fw
Variable = Fw[Fx:1  Fy:1 Fz:1]
Variable DOFs = 3
End

! Solve this for body Id 2 (=boundary 3 here)
Equation 2
Active Solvers(1) = 1
End

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Boundary Condition 3
Target Boundaries = 5
Body Id = 2
External Pressure = Real 0.1
End```

### Examples

In the example found in `[ELMER_TRUNK]/elmerice/Tests/ForceToStress`, a pressure applied on a boundary is first integrated to get nodal force using the `GetHydrostaticLoads` solver, and then the pressure is recovered using the ForceToStress Solver.