Changes between Version 12 and Version 13 of u/erica/AccretionModelingBlog


Ignore:
Timestamp:
03/20/18 19:30:25 (7 years ago)
Author:
Erica Kaminski
Comment:

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  • u/erica/AccretionModelingBlog

    v12 v13  
    11== Bondi Accretion ==
    22
    3 === 3/18/2018 ($\gamma=1.66$ case)===
     3=== 3/18/2018 ===
    44
    55Am working on a 3D simulation of Bondi Flow onto a central sink particle and studying the accretion properties using the Krumholz accretion algorithm.
    … …  
    5252[[Image(Bondi_Comparison.png, 50%)]]
    5353
    54 The profiles are cut-off within an inner radius of $r=.875$ to avoid extremely high speeds there (am going to get rid of this in the next round of sims). Sampling the mass flux across a spherical shell less than this radius doesn't match up with the theoretical prediction of $\dot{M}=2692$ since the solution is getting stepped on there. Sampling the mass flux across a shell larger than this, however, produces agreement. 
     54The profiles are cut-off within an inner radius of $r=.875$ to avoid extremely high speeds there (am going to get rid of this in the next round of sims). Sampling the mass flux across a spherical shell less than this radius doesn't match up with the theoretical prediction of $\dot{M}=2692$ since the solution is getting stepped on there. Sampling the mass flux across a shell larger than this, however, produces agreement (2689 compared to 2692). 
    5555
     56Since the solution is getting stepped on within some small inner radius, can't meaningfully check the behavior of the accretion algorithm and any spurious waves it might be generating there. Instead, will be removing this inner boundary in the next run. Would like to test the effect of the sonic radius being outside of the accretion radius as opposed to within. To test this will do a resolution study on $\gamma=7/5$ flow, where the sonic point is $~.2R_{BH}$.
    5657
     58As the following images show, this set of conditions produces a steady state solution... Both the sonic point is not-resolved, as well as the solution is being stepped on where non-steady effects could happen due to effects of the accretion algorithm. The attached module files that produce these files are thus called "*_steadystate*"
    5759
    58 However, the accretion rate onto the particle does not match the theoretical value. Sampling the mass of the particle over 10 different times shows the accretion rate to be fairly constant at,
    59 
    60 $\dot{M}_{sink}=405$
    61 
    62 (note, the sim was ran for about the freefall time of the average density in the box)
    63 
    64 || Mesh || [[Image(mesh_comparison.png, 50%)]] ||
    65 || Radial velocity || [[Image(vr.png, 50%)]] ||
    66 || Radial mach || [[Image(radial_mach.png, 50%)]] ||
    67 || Radial mach || [[Image(radial_mach.png, 50%)]] ||
    68 || Velocity field || [[Image(vec_comparison.png, 50%)]] ||
    69 || Clipped mass over time (r<1) || [[Image(clipped_mass.png, 50%)]] ||
    70 || Isosurface (r=rsink) || [[Image(isosurface.png, 50%)]] ||
    71 || Mass flux (r=rsink) || [[Image(massflux.png, 50%)]] ||
     60|| Mesh || [[Image(mesh_comparison.png, 25%)]] ||
     61|| Radial velocity || [[Image(vr.png, 25%)]] ||
     62|| Radial mach || [[Image(radial_mach.png, 25%)]] ||
     63|| Velocity field || [[Image(vec_comparison.png, 25%)]] || 
     64|| Isosurface (r=rsink) || [[Image(isosurface.png, 25%)]] ||
     65|| Mass flux (r=rsink) || [[Image(massflux.png, 25%)]] ||
    7266
    7367== Library ==