To begin preparing the nanoFluidX model, an SPH Flow
Solution must be defined in SimLab and dedicated to
nanoFluidX. This is available from Solutions > Application > SPH Flow Solution. Figure 1.
Solution type
Currently there two solutions: Drivetrain Oiling and Vehicle Wading.
Future versions will add further solution types for different use
cases.
Select bodies
Select the bodies to be included in the simulation. Only the bodies
selected will be used for the simulation, even though there are more
bodies in the SimLab database. Currently CAD
bodies are not supported in the solution, only tessellated/meshed FEM
bodies are permitted.
Physics
Interaction Scheme
Choose whether to use Riemann or Weighted interaction schemes
(interactionscheme). Weighted is the default choice and is capable of
handling violent and chaotic multiphase flows. Riemann results in
smoother pressure gradients and less breakup of sprays and jets but will
experience local instabilities with more violent flows.
When using Weighted interaction, Transport Velocity and Free Surface
should be set in simulation parameters. Riemann interaction offers some
advanced controls, but these should not require adjustment.
Surface Tension
Choose if surface tension is active (surften_model) and which model to
use. By default, surface tension is disabled, since it adds
computational cost.
When creating a multiphase simulation, ADAMI should be chosen. This uses
a physical value of surface tension coefficient (surf_ten) which can be
calculated.
For single-phase simulations, SINGLE_PHASE or TARTAKOVSKY should be
chosen. The Tartakovsky model has the advantage in that a physical value
of surface tension coefficient (surf_ten) can be calculated and
used.
Note: Surface Tension requires reference
curvature (ref_curv) to be set in Domain parameters, along with
surface tension coefficient (surf_ten) in Material (phase)
parameters.
Adhesion
Specifies whether the Akinci wall adhesion model (adhesion_model) is
active. This is used in conjunction with surface tension to define how
the fluid interacts with the wall and the contact angle of a fluid
droplet on the wall.
Important: Adhesion Coefficient (adhesionCoeff) must also be set in Material
(phase) parameters when using the adhesion model.
Temperature
Activates energy_transport so that the energy equation is solved by
nanoFluidX for conduction and convection
heat transfer.
Important: When
Temperature is used, initial temperature (temp_0), evolve
temperature flag (evolve_temp), specific heat capacity of the
material (heat_cap) and heat conduction coefficient of the material
(heat_cond) should be set in Material (phase) parameters.
Temperature and Flux output should also be requested in Results
Request.
