With this option no turbulence model is applied, therefore, it will be appropriate only for low Reynolds number flows. In this case, the Morris viscosity approximation [3] is more suitable.

While the laminar option is suitable for low Reynolds number flows, it does not capture the main features of the flow when turbulence is predominant. Using the concepts of Large Eddy Simulation (LES), the model proposed by Violeau and Issa (2007) [5] computes the effective viscosity, which replaces the constant value of molecular viscosity in the viscous acceleration term, as the sum of that viscosity and the turbulent viscosity:

(2–22)

where and are the molecular and turbulent dynamic viscosities for element a.

The turbulent viscosity , is computed as:

(2–23)

where is the Smagorinsky constant, given by LES Smag. Const., which is a method parameter with a default value of 0.2; and is the characteristic length equivalent to the grid size, computed as:

(2–24)

where is given by LES Dist. Fact., which is a method parameter with a default value of 2, and is the initial SPH elements spacing.

In Eq. Equation 2–23, is the scalar mean rate-of-strain for element a, and is calculated as:

(2–25)