Algorithm Options

Conservative vs. Non-conservative

The following must be preceded by “ns.”

	Description	Type	Default
do_mom_diff	If 0, solve velocity equation in convective form, else use conservation form	Int	0
do_cons_trac	If 0, solve for a passively advected tracer, else advect conservatively	Int	0
do_cons_trac2	If 0, solve for a passively advected 2nd tracer, else advect conservatively	Int	0

Note that Temperature is only non-conservative. For more details, see Fluid Equations.

Advection

IAMR has the option to use a Method of Lines (MOL) or Godunov scheme to compute the advective terms.

	Description	Type	Default
ns.use_godunov	If true, use Godunov, else use MOL.	bool	true

For problems without embedded boundaries, there are additional options when using the Godunov method. The following must be preceded by “godunov.”

	Description	Type	Default
use_ppm	Use the Piecewise Parabolic Method to construct edge states	bool	false
use_forces_in_trans	Use external forcing terms in constructing transverse derivatives	bool	false

Diffusion

The following must be preceded by “ns.”

	Description	Type	Default
be_cn_theta	Diffusion solve fully implicit (1.0) or semi-implicit (<1 && >0.5)	Real	0.5

Note the default value of ns.be_cn_theta = 0.5 corresponds to the Crank-Nicolson method.