Changes between Version 128 and Version 129 of doc/app/particle_parameters

Timestamp:

Apr 7, 2016 12:34:22 PM (9 years ago)

Author:

hoffmann

Comment:

--

doc/app/particle_parameters

@@ -100 +100 @@
       Droplet collision is switched off.
 
-'' 'palm' ''
-      The collision kernel is approximated using a method from Rogers and Yau (1989, A Short Course in Cloud Physics, Pergamon Press). All droplets smaller than the treated one are represented by one droplet with mean features. Collision efficiencies are taken from the respective table in Rogers and Yau.
-
 '' 'wang' ''
       Beside gravitational effects (treated with the Hall-kernel) also the effects of turbulence on the collision are considered using parameterizations of Ayala et al. (2008, New J. Phys., 10, 075015) and Wang and Grabowski (2009, Atmos. Sci. Lett., 10, 1-8). This kernel includes three possible effects of turbulence: the modification of the relative velocity between the droplets, the effect of preferential concentration, and the enhancement of collision efficiencies.
@@ -110 +107 @@
 
 '''Attention:''' Switching on the collision process drastically increases the CPU time of jobs.
+}}}
+|----------------
+{{{#!td style="vertical-align:top"
+[=#collision_algorithm '''collision_algorithm''']
+}}}
+{{{#!td style="vertical-align:top"
+C*15
+}}}
+{{{#!td style="vertical-align:top"
+'all_or_nothing'
+}}}
+{{{#!td
+Parameter to steer the algorithm for cloud droplet growth by collision.\\\\
+
+By default, the collision algorithm is set to 'all_or_nothing'. The user can choose between the following algorithms:\\\\
+
+'' 'all_or_nothing' ''
+      Probabilistic collision algorithm based on the ideas of Shima et al. (2009) and Sölch and Kärcher (2010).  Each particles represented by one superdroplet grows by the collection of one particle of another superdroplet if the probability for this event if larger than a random number.
+
+'' 'average_impact' ''
+      Original PALM collision algorithm (Riechelmann et al, 2012), in which the average grow of every superdroplet is calculated. In contrast to the  'all_or_nothing' algorithm, the number of collected particles is equally distributed over the collecting particles, i.e., a particle might grow by collecting a certain fraction of particles.  
+
+}}}
+|----------------
+{{{#!td style="vertical-align:top;width: 150px"
+[=#curvature_solution_effects '''curvature_solution_effects''']
+}}}
+{{{#!td style="vertical-align:top;width: 50px"
+L
+}}}
+{{{#!td style="vertical-align:top;width: 75px"
+.F.
+}}}
+{{{#!td
+Parameter to consider solution and curvature effects on the equilibrium vapor pressure of cloud droplets.
+
+This parameter only comes into effect if Lagrangian cloud droplets are used (see [#cloud_droplets cloud_droplets]) and if the droplet radius is smaller than ''1.0E-6'' m. In case of '''curvature_solution_effects''' = ''.T.'', solution and curvature effects are included in the growth equation of droplets by condensation. Since in this case the growth equation is a stiff o.d.e, it is integrated in time using the Rosenbrock method (see Numerical Recipes in FORTRAN, 2nd Edition, p.731). If the droplet radius is larger or equal ''1.0E-6'' m, solution and curvature effects are neglected and the growth is calculated by a simple analytic formula (as for '''curvature_solution_effects''' = ''.F.'').\\\\
+'''Attention:''' '''curvature_solution_effects''' = ''.T.'' may significantly increase CPU time of jobs.
 }}}
 |----------------