Changes between Version 117 and Version 118 of doc/app/particle_parameters

Timestamp:

Feb 19, 2012 2:40:28 AM (13 years ago)

Author:

raasch

Comment:

--

doc/app/particle_parameters

@@ -87 +87 @@
 Top boundary condition for particle transport.\\
 By default, particles are absorbed at the top boundary. Alternatively, a reflection condition can be set by '''bc_par_t''' = '' 'reflect'. ''
+}}}
+|----------------
+{{{#!td style="vertical-align:top"
+[=#collision_kernel '''collision\\_kernel''']
+}}}
+{{{#!td style="vertical-align:top"
+C*15
+}}}
+{{{#!td style="vertical-align:top"
+'none'
+}}}
+{{{#!td
+Parameter to steer cloud droplet growth by collision processes.\\\\
+
+The growth of cloud droplets due to collision is parameterized using the so-called collision kernel. By default, collision is switched off. The user can choose between the following kernels:\\\\
+
+'' 'hall' ''
+      Collision kernel from Hall (1980, J. Atmos. Sci., 2486-2507), which considers collision due to pure gravitational effects. Larger droplets have a higher terminal fall velocity and are collecting smaller ones. Only terminal droplet velocities are considered in this kernel (not their effective velocities).
+
+'' 'none' ''
+      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.
+
+'''Attention:''' Switching on the collision process drastically increases the CPU time of jobs.
 }}}
 |----------------
@@ -526 +555 @@
 |----------------
 {{{#!td style="vertical-align:top"
-[=#turbulence_effects_on_collision '''turbulence_effects\\_on_collision''']
-}}}
-{{{#!td style="vertical-align:top"
-L
-}}}
-{{{#!td style="vertical-align:top"
-.F.
-}}}
-{{{#!td
-Parameter to switch on turbulence effects for calculation of cloud droplet growth due to collision.\\\\
-
-For '''turbulence_effects_on_collision''' = ''.T.'' a turbulent collision kernel is used for the calculation of the cloud droplet growth due to collision. This turbulent collision kernel includes three possible turbulence effects: the modification of the relative velocity between the droplets, the effect of preferential concentration and the enhancement of the collision efficiencies. The turbulence effects are calcuclated using parameterizations of Ayala et al. (2008, New J. Phys., 10, 075015) and Wang and Grabowski (2009, Atmos. Sci. Lett., 10, 1-8). \\\\
-
-'''Note: turbulence_effects_on_collision''' = ''.T.'' requires [#wang_collision_kernel wang_collision_kernel] = ''.T.'', since the turbulence effects can only be considered during explicit calculation of the collision kernel.
-}}}
-|----------------
-{{{#!td style="vertical-align:top"
 [=#use_particle_tails '''use_particle_tails''']
 }}}
@@ -588 +600 @@
 |----------------
 {{{#!td style="vertical-align:top"
-[=#wang_collision_kernel '''wang_collision\\_kernel''']
-}}}
-{{{#!td style="vertical-align:top"
-L
-}}}
-{{{#!td style="vertical-align:top"
-.F.
-}}}
-{{{#!td
-Parameter to steer the calculation of the cloud droplet growth due to collision.\\\\
-
-The growth of a cloud droplet due to collision is parameterized using the so-called collision kernel. By default, the collision kernel is approximated using a method from Rogers and Yau (1989, A Short Course in Cloud Physics, Pergamon Press). In this case the collision efficiencies necessary for this calculation are also taken from Rogers and Yau. With '''wang_collision_kernel''' = ''.T.'' the collision kernel is calculated explicitly and collision efficiencies from Hall (1980, J. Atmos. Sci., 2486-2507) are used. 
-}}}
-|----------------
-{{{#!td style="vertical-align:top"
 [=#write_particle_statistics '''write_particle\\_statistics''']
 }}}