Algortihm Options
Conservative vs. Nonconservative
The following must be preceeded 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 nonconservative. 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 preceeded 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 preceeded by “ns.”
Description 
Type 
Default 


be_cn_theta 
Diffusion solve fully implicit (1.0) or semiimplicit (<1 && >0.5) 
Real 
0.5 
Note the default value of ns.be_cn_theta = 0.5
corresponds to the CrankNicolson method.