Changes between Version 19 and Version 20 of AccretionDiskTutorial

Timestamp:

08/29/12 11:40:57 (14 years ago)

Author:

idilernia

Comment:

—

AccretionDiskTutorial

@@ -31 +31 @@
 - Height: the height of the disk
 - Ambient: the blue portion of the plot, it represents the area around the disk
-- !PointGravity: a point mass located at the center of the disk
+- !PointGravity: a point mass located at the center of the disk, not visible in this picture
 
 '''Note''': Numerical values reported by Visit are in computational units, ''scales.data'' contains the scales values needed to translate computational units to physical units.
@@ -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
 
-|| ddensity=1d0       || disk density ||
-|| adensity=0.001d0   ||ambient density||
-|| dtemp=1d4          ||disk temperature||
-|| atemp=6d6          ||ambient temperature||
-|| radius=2e10        ||disk radius||
-|| height=5e9         ||disk height||
-|| mass=.6d-1         ||central particle mass||
+|| ddensity=1d0       || disk density (g/cc or particles/cc)||
+|| adensity=0.001d0   ||ambient density (g/cc or particles/cc)||
+|| dtemp=1d4          ||disk temperature (K)||
+|| atemp=6d6          ||ambient temperature (K)||
+|| radius=2e10        ||disk radius (cm)||
+|| height=5e9         ||disk height (cm)||
+|| mass=.6d-1         ||central particle mass (g)||
 
 '''Note:''' for this specific module, problem.data no scaling operation is required from the user
@@ -61 +61 @@
 
 [[CollapsibleStart(Setting pressure)]]
-hello
+By default, the accretion disk module lets you set the temperature for a problem, however, in the case you want to set pressure there are two options:
+- Use of the equation of state to calculate temperature depending on pressure and density
+- Manual modification of problem.f90 to initialize the problem using pressure parameters
+
+For the second option, it may be sufficient to examine a few lines of ''!ProblemModuleInit'' contained in problem.f90:
+
+{{{
+Ambient%pressure= adensity*atemp/rScale/TempScale !cu
+}}}
+
+the line above sets up the ambient pressure depending of density and temperature set in ''problem.data'', if we change it to
+
+{{{
+Ambient%pressure= atemp/pScale
+}}}
+
+the value contained in ''atemp'' will be interpreted as the pressure in physical units.[[BR]]
+'''Note:''' If are considering to make this change in the code, you are strongly advised to change variable names to avoid misleading nomenclature.
 
 [[CollapsibleEnd]]
@@ -79 +96 @@
 }}}
 
-In the values listed above the disk radius is set to 2e10cm, with that, we set our length scale parameter (lScale) to be .5e10cm[[BR]]
-the resulting ratio R,,disk,,/lScale is 4.[[BR]]
+'''Density scale'''[[BR]]
+There are two options to set a density scale, you can choose either one:[[BR]]
+- ''nScale'' in particles/cc
+- ''rScale'' in g/cc
+
+'''Length scale'''[[BR]][[BR]]
+In the values listed above the disk radius is set to 2e10cm, with that, we set our length scale parameter (lScale) to be .5e10cm:[[BR]]
+the resulting ratio R,,disk,,/lScale is '''4'''.[[BR]][[BR]]
 For convenience purposes, a rule of thumb is to keep the R,,disk,,/lScale within about one order of magnitude from the value above:[[BR]]
-for example, if we had 2e15 as R,,disk,, a good lScale would be .5e15 or 1e15.
+for example, if we had 2e15 as R,,disk,, an ideal lScale would be .5e15 or 1e15.
 
 '''Warning:''' Always make sure to check ''physics.data'' for