Boundary Conditions

This section lists all the boundary conditions available in PyLaBolt, and how to set them in simulations.

Fluid boundary conditions

This section covers the boundary conditions that can applied to fluid flow simulations.

  • bounceBack - Implements no-slip boundary conditions at walls via the halfway bounce-back method. entity type should be set to wall in order to compute forces and torque acting on the boundary.

  • fixedU - Provides a Dirichlet boundary condition for velocity via the halfway bounce-back method. When specified, a fixed velocity is assigned at the concerned boundary. entity type wall allows computation of forces and torque on the boundary, whereas, for inlet or outlet type of boundaries, where force and torque computation isn’t required, the entity type can be set to patch.

  • fixedPressure - Provides a Dirichlet boundary condition for pressure via the halfway bounce-back method. For inlet or outlet, set entity type to patch. The value keyword takes a float value for pressure. For single phase fluid flow, the pressure can be found from density as \(p = \rho c_s^2\), where \(c_s\) is the speed of sound in lattice units. For more information refer here.

  • Zero gradient boundary condition

  • Periodic boundary condition - The Lattice Boltzmann Method