Low Mach number hydrodynamics solver¶
pyro’s low Mach hydrodynamics solver is designed for atmospheric flows. It captures the effects of stratification on a fluid element by enforcing a divergence constraint on the velocity field. The governing equations are:
with \(\nabla p_0 = \rho_0 g\) and \(\beta_0 = p_0^{1/\gamma}\).
As with the incompressible solver, we implement a cell-centered approximate projection method.
The main parameters that affect this solver are:
section: [driver]
option
value
description
cfl
0.8
section: [eos]
option
value
description
gamma
1.4
pres = rho ener (gamma - 1)
section: [lm-atmosphere]
option
value
description
limiter
2
limiter (0 = none, 1 = 2nd order, 2 = 4th order)
proj_type
2
what are we projecting? 1 includes -Gp term in U*
grav
-2.0
Examples¶
bubble¶
The bubble problem places a buoyant bubble in a stratified atmosphere and watches the development of the roll-up due to shear as it rises. This is run as:
./pyro.py lm_atm bubble inputs.bubble