Phase Parameters
In the “phases”-section the material parameters are defined for different SPH components.
phases
{
phase
{
name Water
type FLUID
rho_0 1000.
dyn_visc 1.e-3
surf_ten 0.1
temp_0 0.
heat_cond 0.
heat_cap 0.
evolve_temp false
rho_compr 0.01
pc_factor 1.0
print_info false
print_phase true
cs 100
rm_rho_theta 1.1
init_vel “0.0 0.0 0.0”
}
phase
{
name Housing
type WALL
heat_cond 0.0
heat_cap 0.0
temp_0 0.0
evolve_temp false
noSlip true
print_info true
print_phase true
adhesionCoeff 0.01
fluidContactPhase 1
makesubphase true
init_vel “0.0 0.0 0.0”
}
phase
{
name Something_moving
type MOVINGWALL
rho_0 1.0
heat_cond 0.0
heat_cap 0.0
temp_0 0.0
evolve_temp false
noSlip true
print_info true
print_phase true
adhesionCoeff 0.01
fluidContactPhase 1
makesubphase true
init_vel “0.0 0.0 0.0”
}
…
}
- name
- The name of this phase. Note: This does not need to match with the component name in SimLab.
- type
- The type of the phase defines the physical behavior.
- rho_0
- The reference density of this phase.
- dyn_visc
- The dynamic viscosity of this phase in [kg / (m s), Pa s].
- heat_cap
- The specific heat capacity at constant pressure (Cp) of this phase.
- heat_cond
- The heat conductivity of this phase.
- evolve_temp
- This flag can be used to set the temperature of a phase constant or to allow it to evolve according the energy equation.
- noSlip
- Switch to enable the wall or moving wall to become a slip or no-slip boundary condition.
- temp_0
- The initial temperature of a phase in Kelvin [K].
- surf_ten
- The surface tension coefficient [N/m].
- rho_compr
- The compressibility of the fluid.
- pc_factor
- Background correction pressure associated with the transport velocity formulation. It can have an arbitrary value, however it is generally recommended to keep it on the same order of magnitude of the p0 (base pressure).
- print_info
- If this Boolean flag is set to true, an additional file is written during the simulation with the filename name_info.txt (name is the phase name as defined earlier). The content is written every #N steps (see dt_phaseinfo) and contains information on for example the forces, torques, kinetic energy, center-of-mass etc. of this phase.
- print_phase
- This Boolean flag switches the output of this phase on or off. This switch is useful to limit the amount of output since wall particles for example, do not change their position in time and might not be necessary in the output.
- cs
- Specify the speed of sound in the FLUID phases (individually).
- rm_rho_theta
- Scaling parameter designed to enable local particle density
reinitialization once the threshold of
rho_0*rm_rho_theta is
exceeded.Restriction: This parameter is only available and meaningful when Riemann scheme is used.
- rm_beta
- Numerical parameter used in the low-dissipation Riemann solver. It determines the level of numerical dissipation being introduced in the pair-wise interactions.
- adhesionCoeff
- Scalar value that determines the strength of adhesion force of the fluid particles to the material. Tested range goes from 0.001 to 2.0.
- fluidContactPhase
- Specifying this command in the phase definition will automatically enable tracking of time which the WALL or MOVINGWALL phase spends in contact with the specified fluid phase. This tracked output will be written in the respective particle output file.
- makesubphase
- nanoFluidX has undergone some structural changes and now includes optional use of the sub-phasing. For more details, see Theory and Advanced Features.
- init_vel
- This command can be applied to all phase types, but depending on whether it is a solid or a fluid, it will have different behavior.