Changes between Version 24 and Version 25 of u/erica/SteadyStateAccretionProblemPage
- Timestamp:
- 02/26/19 17:23:50 (6 years ago)
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u/erica/SteadyStateAccretionProblemPage
v24 v25 11 11 Initial conditions are here: [[attachment:InitialConditions.pdf]] 12 12 13 === 128^3^, fixed grid ===13 === Fixed grid === 14 14 15 At this resolution (dx=.03125), the critical radius (rcrit=.0158) is contained within the kernel (r_acc=.125), but below the grid scale (r_min=.027). (Note r_min is the radius of the nearest cell to the sink particle). So, the soln doesn't turn over the way it does in the above plots, at this resolution. Instead, the density and radial velocity are monotonic. 15 Fiducial run is at 128^3^. At this resolution (dx=.03125), the critical radius (rcrit=.0158) is contained within the kernel (r_acc=.125), but below the grid scale (r_min=.027). (Note, r_min is the radial distance between the nearest cell and the sink particle). So, the soln doesn't turn over the way it does in the above plots, at this resolution. Instead, the density and radial velocity are monotonic. 16 16 17 17 A density comparison of the new algorithm (left) vs. the Krumholz algorithm (right): … … 35 35 [[Image(vr_SubcritSubsonic.gif, 25%)]] 36 36 37 === = Testing AMR compatibility ====37 === Testing AMR compatibility === 38 38 39 Image comparing 128^3^ fixed grid (left) vs. 64^3^ + 1 level (right) 20 frames into simulation :39 Image comparing 128^3^ fixed grid (left) vs. 64^3^ + 1 level (right) 20 frames into simulation (or about 40% the crossing time of a sound wave traveling from the outer fixed boundary to the accretion kernel, i.e. $c_s=1$ in computatinonal units): 40 40 41 41 [[Image(AMRcomparisonSubSub.png, 35%)]] 42 42 43 There are slight differences between the runs (peak density/velocity, e.g.)...43 There are only slight differences between the runs (peak density/velocity, e.g.), so this looks pretty good... 44 44 45 === = Running at higher resolution ====45 === Running w/ AMR === 46 46 47 At 128^3^ + 1 level, dx_min=0.015625, which means the critical radius (r_crit=.0158) is slightly above the grid scale (r_min=.0135) and contained within the kernel (r_acc=.0625) . (Note r_min is the radius of the nearest cell to the sink particle).47 To boost runtime speeds, am now switching to testing in AMR... 48 48 49 Here's a lineout of the initial density, radial velocity, and mach number of this flow: 49 ==== 128 + 1 ==== 50 At 128^3^ + 1 level, dx_min=0.015625, which means the critical radius (r_crit=.0158) is slightly above the grid scale (r_min=.0135) and contained within the kernel (r_acc=.0625) . (Recall, r_min is the distance of the nearest cell to the sink particle). In the following, can see comparisons to the Krumholz module at the same resolution.. 51 52 * **Note,** running the code with the Krumholz algorithm produces ''7 frames/minute'' on 24 cores (Bluehive) compared to the new code, which produces ''5 frames/min'' (both using the optimized version of the code, and identical initial conditions). So the new code is slightly slower... 53 54 Here's the density-- 50 55 51 56 [[Image(rho_128plus1_subsubsonic0000.1.png, 25%)]] … … 53 58 [attachment:rho_128plus1_subsubsonic1.gif movie] 54 59 60 mach-- 61 55 62 [[Image(u_128plus1_subsubsonic0000.1.png, 25%)]] 56 63 57 64 [attachment:u_128plus1_subsubsonic.gif movie] 58 65 66 and radial velocity-- 59 67 60 68 [[Image(vr_128plus1_subsubsonic0000.1.png, 25%)]]
