Bondi update - April 30

Two Bondi runs: gam=1.0001, gam=1.4

In each case, the Bondi radius (GM/cs_inf2) is resolved by the same number of zones (~160).

Gam=1 doesn't blow up, but gam=1.4 does. It seems this can be attributed to adiabatic pressure increase in the kernel (due to mass pile up) that sends out a shock wave upstream into the Bondi flow. Does the pressure increase in the kernel support this?

Movies are here:

gam=1.4
Density: gam1pt4_rho.gif​
Pressure (ram vs. thermal): gam1pt4_press.gif​
Speeds (sound vs. vmag): gam1pt4_speeds.gif​

gam=1
Density: gam1_rho.gif​
Pressure (ram vs. thermal): gam1_press.gif​
Speeds (sound vs. vmag): gam1_speeds.gif​

A comparison of the density and pressure at frame 0 and 1 for the different gamma cases is here:

And pressure is here:

These are the same physical time. I think the dynamical time is set by the gas properties at infinity, in which case these should also be the same dynamical time…

Lastly, mdot converges to its theoretical value in the gam=1 case, but not gam=1.4 case:


The Bondi and accretion algorithm mdots are calculated from different expressions. Classical Bondi mdot is:

whereas the Krumholz prescription uses:

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