There are several types of boundary conditions that can be specified in Ansys Forte. These include inflow, outflow, rigid (moving or stationary) walls, periodic, and symmetry boundaries. There are several types of rigid-wall conditions for momentum and energy equations. Wall boundary conditions for the momentum equation include free-slip velocity, no-slip velocity, and turbulent law-of-the-wall conditions. Wall boundary condition options for the energy equation include adiabatic walls and fixed-temperature walls. For in-cylinder engine simulations, the turbulent law-of-the-wall velocity condition and fixed-temperature walls are usually employed. The following sections describe in more detail each of the boundary-condition options available.