SPH Flow Solution

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.


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.
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.
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.


dx sets the particle spacing to be used for the simulation. For guidance on selecting dx, see Particle Resolution - how to decide dx.

Start time (t_begin) is 0 by default. This only needs to be adjusted when running a restart simulation.

End time (t_end) defines the finishing time of the simulation.