Update 2/7: Wind Tunnel Run004 & 005
Finished Runs
Finished Run
WT Run 004A
- Unless otherwise mentioned, same setup with Run003.
- From now on self gravity is enabled. Compared to Run003, this slows down the sim within order of 2, as expected.
- mu set to 0.62, average mu of the Sun. This changed the temperature, but the pressure and the sound speed is not changed. And thus Bondi radius is also unaffected.
- Slight change of timescale - one wind passing time of the box.
- I did not understand the softening length properly: it's set in CU, thought it was set in # of cells. So previously I have been using 10CU=20 cells. For this run I'm using 8CU = 16 cells. Will discuss this a bit more later.
- Simulation time = 0.5CU = 2.57 days
- Wind temp = 3.45e5K
- Sim parameters:
- Spacial resolution: base 643, finest 10243 (4 levels)
- Time Resolution: 0.005CU = 2.2e3s
- Accretion = none
- Hydro solver BC: extrapolated
- Self graivty Poisson solver BC: Periodic
- Poisson solver convergence tolerance: 1e-6
- Run time: less than a day.
Run 004A logRho plot movie:
Run 004A Mach number movie:
WT Run 004B
Setup is identical with Run 004A except that Krumholtz accretion is turned on. The radius of the particle (accretion radius) is set to 1. That is the main flaw of this run: the accretion radius is deep within the softening length, meaning the density sampled for the Krumholtz procedure to estimate the Bondi accretion rate is inaccurate. This motivated Run005s': to have the accretion radius be at least as large as the softening length. Ideally of course accretion radius should be larger, so that the correctly calculated densities of surrounding gas can be sampled. Within the softening length, without graivity, pressure should become equalized, meaning the density profile would be flatter than what we expect realistically. This would surely impact the performance of Krumholtz procedure.
Due to space constraints I did not make movies of 004B, though it can be easily reproduced.
WT Run 005A
- This is anagolous to Run004A, but with a factor of 2 higher resolution. This enables the softening length to be reduced to 4CU, while still resolved by 16 pixels. Bondi radius is around 18 CU.
- To save time Poisson solver's tolerance is set to 1e-3.
- After running for 1.5 days, first 50 frames (0.25CU) was produced. The remaining wall time is at 4.2 days and increasing. I thus decided to end the simulation. As a proof-of-concept this resolution would require an order of magnitude increase in computational resources, which is not unfeasible on Bluehive, but if possible to run it on a better computer, it would be great. Although a larger box is needed for a steady state to be reached.
Attachments (2)
- Run004LogRho.gif (3.6 MB) - added by 7 years ago.
- Run004AMach.gif (11.2 MB) - added by 7 years ago.
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