of tables above: Standard table:\\ ||='''Parameter Name''' =||='''FORTRAN Type''' =||='''Default Value''' =||='''Explanation''' =|| |---------------- {{{#!td style="vertical-align:top; text-align:left;width: 150px" [=#dt_prel '''dt_prel'''] }}} {{{#!td style="vertical-align:top; text-align:left;style="width: 50px" R }}} {{{#!td style="vertical-align:top; text-align:left;style="width: 100px" 9999999.9 }}} {{{#!td Temporal interval at which particles are to be released from a particle source (in s).\\ By default particles are released only at the beginning of a simulation (t_init=0). The time of the first release (t_init) can be changed with package parameter [#particle_advection_start particle_advection_start]. The time of the last release can be set with the package parameter [#end_time_prel end_time_prel]. If '''dt_prel''' has been set, additional releases will be at ''t = t_init+'''dt_prel''', t_init+2*'''dt_prel''', t_init+3*'''dt_prel''', etc..'' Actual release times may slightly deviate from thesel values (see e.g. [../d3par#dt_dopr dt_dopr]).\\\\ The domain of the particle source as well as the distance of released particles within this source are determined via package parameters [#pst pst], [#psl psl], [#psr psr], [#pss pss], [#psn psn], [#psb psb], [#pdx pdx], [#pdy pdy] and [#pdz pdz]. By default, one particle is released at all points defined by these parameters. The package parameter [#particles_per_point particles_per_point] can be used to start more than one particle per point.\\\\ Up to 10 different groups of particles can be released at the same time (see [#number_of_particle_groups number_of_particle_groups]) where each group may have a different source. All particles belonging to one group have the same density ratio and the same radius. All other particle features (e.g. location of the source) are identical for all groups of particles.\\\\ Subgrid scale velocities can (optionally) be included for calculating the particle advection, using the method of Weil et al. (2004, JAS, 61, 2877-2887). This method is switched on by the package parameter [#use_sgs_for_particles use_sgs_for_particles]. This also forces the Euler/upstream method to be used for time advancement of the TKE (see initialization parameter [../inipar#use_upstream_for_tke use_upstream_for_tke]). The minimum timestep during the sub-timesteps is controlled by package parameter [#dt_min_part dt_min_part]. \\\\ By default, particles are weightless and transported passively with the resolved scale flow. Particles can be given a mass and thus an inertia by assigning the package parameter density_ratio a non-zero value (it defines the ratio of the density of the fluid and the density of the particles). In these cases their radius must also be defined, which affects their flow resistance. \\\\ Boundary conditions for the particle transport can be defined with package parameters [#bc_par_t bc_par_t], [#bc_par_lr bc_par_lr], [#bc_par_ns bc_par_ns] and [#bc_par_b bc_par_b].\\\\ Timeseries of particle quantities in netCDF format can be output to local file [../iofile#DATA_1D_PTS_NETCDF DATA_1D_PTS_NETCDF] by using package parameter [#dt_dopts dt_dopts].\\\\ For analysis, additional output of particle information in equidistant temporal intervals can be carried out using [#dt_write_particle_data dt_write_particle_data] (file [../iofile#PARTICLE_DATA PARTICLE_DATA]).\\\\ Statistical informations (e.g. the total number of particles used, the number of particles exchanged between the PEs, etc.) are output to the local file [../iofile#PARTICLE_INFOS PARTICLE_INFOS], if switched on by the parameter [#write_particle_statistics write_particle_statistics]. \\\\ If a job chain is to be carried out, particle informations for the restart run (e.g. current location of all particles at the end of the run) is output to the local file [../iofile#PARTICLE_RESTART_DATA_OUT PARTICLE_RESTART_DATA_OUT], which must be saved at the end of the run and given as an input file to the restart run under local file name [../iofile#PARTICLE_RESTART_DATA_IN PARTICLE_RESTART_DATA_IN] using respective file connection statements in the '''mrun''' configuration file. \\\\ The output of particles for visualization with the graphic software '''dvrp''' is steered by the package parameter [../dvrpar#dt_dvrp dt_dvrp]. For visualization purposes particles can be given a diameter using the parameters [../dvrpar#dvrp_psize dvrp_psize] and [../dvrpar#particle_dvrpsize particle_dvrpsize] (this diameter only affects the visualization). All particles have the same size. Alternatively, particles can be given an individual size and a color by modifying the user-interface ''(subroutine user_init_particles)''. Particles can pull a ''tail'' behind themselves to improve their visualization. This is steered via the parameter [#use_particle_tails use_particle_tails].\\\\ '''So far, the particle transport realized in PALM does only work duly in case of a constant vertical grid spacing! ''' }}} |---------------- {{{#!td style="vertical-align:top" [=#bc_par_b '''bc_par_b'''] }}} {{{#!td style="vertical-align:top" C*15 }}} {{{#!td style="vertical-align:top" reflect }}} {{{#!td Bottom boundary condition for particle transport. \\ By default, particles are reflected at the bottom boundary. Alternatively, a particle absorption can set by '''bc_par_b''' = '' 'absorb' ''. }}} |---------------- {{{#!td style="vertical-align:top" [=#bc_par_lr '''bc_par_lr'''] }}} {{{#!td style="vertical-align:top" C*15 }}} {{{#!td style="vertical-align:top" cyclic }}} {{{#!td Lateral boundary condition (x-direction) for particle transport. \\ By default, cyclic boundary conditions are used along x. Alternatively, reflection ('''bc_par_lr''' = '' 'reflect' '') or absorption ('''bc_par_lr''' = '' 'absorb' '') can be set. \\ This lateral boundary conditions should correspond to the lateral boundary condition used for the flow (see [../inipar#bc_lr bc_lr]). }}} |---------------- {{{#!td style="vertical-align:top" [=#bc_par_ns '''bc_par_ns'''] }}} {{{#!td style="vertical-align:top" C*15 }}} {{{#!td style="vertical-align:top" cyclic }}} {{{#!td Lateral boundary condition (y-direction) for particle transport.\\ By default, cyclic boundary conditions are used along y. Alternatively, reflection ('''bc_par_ns''' = '' 'reflect' '') or absorption (bc_par_ns = '' 'absorb' '') can be set. \\ This lateral boundary conditions should correspond to the lateral boundary condition used for the flow (see [../inipar#bc_ns bc_ns]). }}} |---------------- {{{#!td style="vertical-align:top" [=#bc_par_t '''bc_par_t'''] }}} {{{#!td style="vertical-align:top" C*15 }}} {{{#!td style="vertical-align:top" absorb }}} {{{#!td 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" [=#density_ratio '''density_ratio'''] }}} {{{#!td style="vertical-align:top" R(10) }}} {{{#!td style="vertical-align:top" 0.0, 9 * 9999999.9 }}} {{{#!td Ratio of the density of the fluid and the density of the particles. \\ With the default value the particles are weightless and transported passively with the resolved scale flow. In case of '''density_ratio''' ''/= 0.0'' particles have a mass and hence inertia so that their velocity deviates more or less from the velocity of the surrounding flow. Particle velocity is calculated analytically and depends on (besides the density ratio and the current velocity difference between particles and surrounding fluid) the particle radius which is determined via [#radius radius] as well as on the molecular viscosity (assumed as 1.461E-5 m2/s). If '''density_ratio''' ''= 1.0'', the particle density corresponds to the density of the surrounding fluid and the particles do not feel any buoyancy. Otherwise, particles will be accelerated upwards ('''density_ratio''' > ''1.0'') or downwards ('''density_ratio''' < ''1.0''). With several groups of particles (see [#number_of_particle_groups number_of_particle_groups]), each group can be assigned a different value. If the number of values given for '''density_ratio''' is less than the number of groups defined by [#number_of_particle_groups number_of_particle_groups]), then the last assigned value is used for all remaining groups. This means that by default the particle density ratio for all groups will be ''0.0''. }}} |---------------- {{{#!td style="vertical-align:top" [=#dt_dopts '''dt_dopts'''] }}} {{{#!td style="vertical-align:top" R }}} {{{#!td style="vertical-align:top" value of [../d3par#dt_data_output dt_data_output] }}} {{{#!td Temporal interval at which time series data of particle quantities shall be output (in s). If particle advection is switched on (see [#dt_prel dt_prel]) this parameter can be used to assign the temporal interval at which time series of particle quantities shall be output. Output is written in netCDF format on local file [../io_file#DATA_1D_PTS_NETCDF DATA_1D_PTS_NETCDF]. The following list gives a short description of the quantities available. Most quantities are averages over all particles. The quantity name given in the first column is identical to the respective name of the variable on the netCDF file. In case of using more than one particle group (see [#number_of_particle_groups number_of_particle_groups]), seperate time series are output for each of the groups. The long names of the variables in the netCDF file containing the respective timeseries all end with the string ''PG'' ##, where ## is the number of the particle group ''(01, 02, etc.)''. \\\\ ||= tnpt =||= total number of particles =|| || x_ || particle x-coordinate with respect to the particle origin (in m) || || y_ || particle y-coordinate with respect to the particle origin (in m) || || z_ || particle z-coordinate with respect to the particle origin (in m) || || z_abs || absolute particle z-coordinate (in m) || || u || u particle velocity component (in m/s) || || v || v particle velocity component (in m/s) || || w || w particle velocity component (in m/s) || || u'' || subgrid-scale u particle velocity component (in m/s) || || v'' || subgrid-scale v particle velocity component (in m/s) || || w'' || subgrid-scale w particle velocity component (in m/s) || || npt_up || total number of upward moving particles || || w_up || vertical velocity of the upward moving particles (in m/s) || || w_down || vertical velocity of the downward moving particles (in m/s) || || npt_max || maximum number of particles in a subdomain (=tnpt for non-parallel runs) || || npt_min || minimum number of particles in a subdomain (=tnpt for non-parallel runs) || || x*2 || variance of the particle x-coordinate with respect to x_ (in m2) || || y*2 || variance of the particle y-coordinate with respect to y_ (in m2) || || z*2 || variance of the particle z-coordinate with respect to z_ (in m2) || || u*2 || variance of the u particle velocity component with respect to u (in m2/s2) || || v*2 || variance of the v particle velocity component with respect to v (in m2/s2) || || w*2 || variance of the w particle velocity component with respect to w (in m2/s2) || || u"2 || variance of the subgrid-scale u particle velocity component with respect to u" (in m2/s2) || || v"2 || variance of the subgrid-scale v particle velocity component with respect to v" (in m2/s2) || || w"2 || variance of the subgrid-scale w particle velocity component with respect to w" (in m2/s2) || || npt*2 || variance of the number of particles with respect to the average number of particles per subdomain || }}} Table row with nesting:\\ {{{#!td style="vertical-align:top" [=# ''''''] }}} {{{#!td style="vertical-align:top" }}} {{{#!td style="vertical-align:top" }}} {{{#!td ||=C1 =||=C2 =|| ||Text1 ||Text2 || }}}