Changes between Version 18 and Version 19 of AccretionDiskTutorial
- Timestamp:
- 08/29/12 10:54:04 (12 years ago)
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AccretionDiskTutorial
v18 v19 8 8 These directions assume that you are able to compile a problem, in case you have never compiled AstroBEAR check the page [https://clover.pas.rochester.edu/trac/astrobear/wiki/BuildingAstroBear How to Build AstroBEAR 2.0] [[BR]] 9 9 10 In order to set up a simple accretion disk simulation proceed to select the BasicDisk problem in the modules folder,10 In order to set up a simple accretion disk simulation proceed to select the !BasicDisk problem in the modules folder, 11 11 this can be done by typing the following commands in the astrobear root directory: 12 12 {{{ … … 27 27 28 28 At his point you should start to get familiar with some of the elements in the image above: 29 - GxBounds: the boundaries of the plot, namely the physical boundaries of the simulation29 - !GxBounds: the boundaries of the plot, namely the physical boundaries of the simulation 30 30 - Radius: the radius of the disk 31 31 - Height: the height of the disk 32 32 - Ambient: the blue portion of the plot, it represents the area around the disk 33 - PointGravity: a point mass located at the center of the disk33 - !PointGravity: a point mass located at the center of the disk 34 34 35 35 '''Note''': Numerical values reported by Visit are in computational units, ''scales.data'' contains the scales values needed to translate computational units to physical units. … … 37 37 == Initial Conditions == 38 38 39 Now you can proceed to examine ''problem.data'' contained in the '' 'BasicDisk''' folder.39 Now you can proceed to examine ''problem.data'' contained in the ''!BasicDisk'' folder. 40 40 The default problem.data file contains a list of initial conditions that can be changed depending on the user's needs, let's analyze some of them 41 41 … … 59 59 10.d0 60 60 }}} 61 62 [[CollapsibleStart(Setting pressure)]] 63 hello 64 65 [[CollapsibleEnd]] 61 66 62 67 == Scales == … … 107 112 - Increased softening radius: the force of gravity has a lower value at r=0 compared to the previous case 108 113 109 Astrobear provides different softening techniques such as SplineSoft andPlummerSoft, the user can set the softening function depending on the simulation needs.114 Astrobear provides different softening techniques such as !SplineSoft and !PlummerSoft, the user can set the softening function depending on the simulation needs. 110 115 111 116 '''Warning: ''' It is good practice to keep the soft_radius between .1 and .3. Failure to do so may result in undesired outcomes. … … 122 127 }}} 123 128 124 MaxLevel regulates the maximum amount of AMR levels, while GmX sets the number of cells in a fixed grid array.[[BR]]129 !MaxLevel regulates the maximum amount of AMR levels, while GmX sets the number of cells in a fixed grid array.[[BR]][[BR]] 125 130 '''Warning:''' global.data contains another array entry, ''Domain%mGlobal'' which should usually be set to (1, 1, 1, GmX(1), GmX(2), GmX(3)), changing Gmx without modifying Domain%mGlobal as well could lead to instabilities. 126 131 … … 131 136 [[Image(visit0040.png, 400px)]] 132 137 133 A subroutine named '' ProblemSetErrFlag'' in ''problem.f90'' is responsible for marking the regions for refinement in our Disk module and giving the Mesh the pattern seen above. [[BR]]138 A subroutine named ''!ProblemSetErrFlag'' in ''problem.f90'' is responsible for marking the regions for refinement in our Disk module and giving the Mesh the pattern seen above. [[BR]] 134 139 Depending on the initial conditions of a specific run it may be the case that a disk undergoes gravitational collapse and its boundaries can expand within reasonable limits. This event can cause a significant part of the disk to outflow the refined area, and a consequential loss of information. 135 140 136 '' ProblemSetErrFlag'' can be altered to address this issue, changing141 ''!ProblemSetErrFlag'' can be altered to address this issue, changing 137 142 138 143 {{{ … … 157 162 == Mach Number == 158 163 159 When setting up a new simulation it is good practice to check that the Mach values are below a certain threshold, in most of computational simulation this value is ~60. [[BR]] Values above this threshold may create difficulties in evolving a model and therefore create computational errors.160 [[BR]] 161 To plot the Mach numbers in Visit you can check the [https://clover.pas.rochester.edu/trac/astrobear/wiki/VisIt Visit page] and locate Mach in the Chombo expressions list [[BR]] 164 When setting up a new simulation it is good practice to check that the Mach values are below a certain threshold, in most of computational simulation this value is ~60. [[BR]][[BR]] Values above this threshold may create difficulties in evolving a model and therefore create computational errors. 165 [[BR]][[BR]] 166 To plot the Mach numbers in Visit you can check the [https://clover.pas.rochester.edu/trac/astrobear/wiki/VisIt Visit page] and locate Mach in the Chombo expressions list [[BR]][[BR]] 162 167 The plot below represents a disk simulation that respects the limits stated above:[[BR]] 163 168 [[Image(mach.png, 500px)]]
