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| 5 | <title>PALM chapter 4.4</title><meta content="StarOffice 7 (Win32)" name="GENERATOR"> |
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| 6 | <meta content="Siegfried Raasch" name="AUTHOR"> |
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| 9 | <meta content="parallel LES model" name="KEYWORDS"> |
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| 16 | <body dir="ltr" lang="en-US"> |
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| 17 | <h3 style="line-height: 100%;">4.4 Example of a minimum parameter set</h3> |
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| 18 | <p style="line-height: 100%;">In this chapter a brief, simple and |
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| 19 | complete parameter set is described, which can be used to carry out a |
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| 20 | model run. The presented example is available via <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/INSTALL/example_p3d">example |
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| 21 | file</a> and can be used (together with the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/INSTALL/.mrun.config">configuration |
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| 22 | file</a> described in <a href="chapter_3.2.html">chapter |
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| 23 | 3.2)</a> for the execution of a simple model run. </p> |
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| 24 | <p style="line-height: 100%;">This run simulates a quasi-stationary, |
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| 25 | convective, atmospheric boundary layer with <font color="#000000">zero |
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| 26 | mean horizontal |
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| 27 | wind.</font> For evaluation purposes, cross sections and horizontally averaged vertical |
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| 28 | profiles of typical boundary layer variables |
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| 29 | are output at the end of the run. The run shall be carried out in |
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| 30 | batch mode on the IBM Regatta "hanni" of the HLRN.</p> |
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| 31 | <p style="line-height: 100%;">The parameter file necessary to carry |
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| 32 | out a run must be provided to the model as an input file under the |
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| 33 | local name <a href="chapter_3.4.html#PARIN">PARIN</a> |
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| 34 | and has the following contents:</p> |
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| 35 | <pre style="line-height: 100%;">&inipar <a href="chapter_4.1.html#nx">nx</a> = <span style="font-style: italic;">39</span>, <a href="chapter_4.1.html#ny">ny</a> = <span style="font-style: italic;">39</span>, <a href="chapter_4.1.html#nz">nz</a> = <span style="font-style: italic;">40</span>,<br> <a href="chapter_4.1.html#dx">dx</a> = <span style="font-style: italic;">50.0</span>, <a href="chapter_4.1.html#dy">dy</a> = <span style="font-style: italic;">50.0</span>, <a href="chapter_4.1.html#dz">dz</a> = <span style="font-style: italic;">50.0</span>,<br> <a href="chapter_4.1.html#dz_stretch_level">dz_stretch_level</a> = <span style="font-style: italic;">1200.0</span>,<br> <a href="chapter_4.1.html#fft_method">fft_method</a> = <span style="font-style: italic;">'temperton-algorithm'</span>,<br> <a href="chapter_4.1.html#initializing_actions">initializing_actions</a> = <span style="font-style: italic;">'set_constant_profiles'</span>,<br> <a href="chapter_4.1.html#ug_surface">ug_surface</a> = <span style="font-style: italic;">0.0</span>, <a href="chapter_4.1.html#vg_surface">vg_surface</a> = <span style="font-style: italic;">0.0</span>,<br> <a href="chapter_4.1.html#pt_vertical_gradient">pt_vertical_gradient</a> = <span style="font-style: italic;">0.0</span>, <span style="font-style: italic;">1.0</span>,<br> <a href="chapter_4.1.html#pt_vertical_gradient_level">pt_vertical_gradient_level</a> = <span style="font-style: italic;">0.0</span>, <span style="font-style: italic;">800.0</span>,<br> <a href="chapter_4.1.html#surface_heatflux">surface_heatflux</a> = <span style="font-style: italic;">0.1</span>, <a href="chapter_4.1.html#bc_pt_b">bc_pt_b</a> = <span style="font-style: italic;">'neumann'</span>,/<br><br>&d3par <a href="chapter_4.2.html#end_time">end_time</a> = <span style="font-style: italic;">3600.0</span>,<br> <a href="chapter_4.2.html#create_disturbances">create_disturbances</a> = <span style="font-style: italic;">.T.</span>,<br> <a href="chapter_4.2.html#dt_disturb">dt_disturb</a> = <span style="font-style: italic;">150.0</span>, <a href="chapter_4.2.html#disturbance_energy_limit">disturbance_energy_limit</a> = <span style="font-style: italic;">0.01</span>,<br> <a href="chapter_4.2.html#dt_run_control">dt_run_control</a> = <span style="font-style: italic;">0.0</span>,<br> <a href="chapter_4.2.html#data_output">data_output</a> = <span style="font-style: italic;">'w_xy'</span>, <span style="font-style: italic;">'w_xz'</span>, <span style="font-style: italic;">'w_xz_av'</span>, <span style="font-style: italic;">'pt_xy'</span>, <span style="font-style: italic;">'pt_xz'</span>,<br> <a href="chapter_4.2.html#dt_data_output">dt_data_output</a> = <span style="font-style: italic;">900.0</span>,<br> <a href="chapter_4.2.html#dt_data_output_av">dt_data_output_av</a> = <span style="font-style: italic;">1800.0</span>,<br> <a href="chapter_4.2.html#averaging_interval">averaging_interval</a> = <span style="font-style: italic;">900.0</span>,<br> <a href="chapter_4.2.html#dt_averaging_input">dt_averaging_input</a> = <span style="font-style: italic;">10.0</span>,<br> <a href="chapter_4.2.html#section_xy">section_xy</a> = <span style="font-style: italic;">2</span>, <span style="font-style: italic;">10</span>, <a href="chapter_4.2.html#section_xz">section_xz</a> = <span style="font-style: italic;">20</span>,<br> <a href="chapter_4.2.html#data_output_2d_on_each_pe">data_output_2d_on_each_pe</a> = <span style="font-style: italic;">.F.</span>,<br> <a href="chapter_4.2.html#dt_dopr">dt_dopr</a> = <span style="font-style: italic;">900.0</span>, <a href="chapter_4.2.html#averaging_interval_pr">averaging_interval_pr</a> = <span style="font-style: italic;">600.0</span>,<br> <a href="chapter_4.2.html#dt_averaging_input_pr">dt_averaging_input_pr</a> = <span style="font-style: italic;">10.0</span>,<br> <a href="chapter_4.2.html#data_output_pr">data_output_pr</a> = <span style="font-style: italic;">'#pt'</span>, <span style="font-style: italic;">'w”pt”'</span>, <span style="font-style: italic;">'w*pt*'</span>, <span style="font-style: italic;">'wpt'</span>, <span style="font-style: italic;">'w*2'</span>, <span style="font-style: italic;">'pt*2'</span>,<br> <a href="chapter_4.2.html#cross_profiles">cross_profiles</a> = <span style="font-style: italic;">' pt '</span>, <span style="font-style: italic;">' w"pt" w*pt* wpt '</span>, <span style="font-style: italic;">' w*2 '</span>, <span style="font-style: italic;">' pt*2 '</span>,<br> <a href="chapter_4.2.html#cross_xtext">cross_xtext</a> = <span style="font-style: italic;">'pot. temperature in K'</span>,<br> <span style="font-style: italic;">'heat flux in K ms>->1'</span>,<br> <span style="font-style: italic;">'velocity variance in m>2s>->2'</span>,<br> <span style="font-style: italic;">'temperature variance in K>2'</span>,<br> <a href="chapter_4.2.html#z_max_do1d">z_max_do1d</a> = <span style="font-style: italic;">1500.0</span>, /</pre> |
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| 36 | <p style="line-height: 100%;"><br> |
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| 37 | <br> |
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| 38 | </p> |
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| 39 | <p style="line-height: 100%;">The initialization parameters (<tt><font style="font-size: 10pt;" size="2">&inipar</font></tt>) |
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| 40 | are located at the beginning of the file. For analysis of a |
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| 41 | convective boundary layer of approx. 1000 m thickness the horizontal |
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| 42 | size of the model domain should amount to at least 2 km x 2 km. In |
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| 43 | order to resolve the convective structures a grid spacing of <b>dx</b> |
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| 44 | = |
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| 45 | <b>dy</b> = <b>dz</b> = <i>50 m</i> is enough, since the typical |
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| 46 | diameter of convective plumes is more than 100 m. Thereby the |
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| 47 | upper array index in the two horizontal directions needs to be <b>nx</b> |
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| 48 | = <b>ny</b> = <i>39</i>. <font color="#000000">Since in |
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| 49 | each case the lower array index has the value 0, 40 grid points are |
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| 50 | used along both horizontal directions.</font> In the vertical direction |
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| 51 | the domain must be high enough to include the entrainment processes at |
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| 52 | the top of the boundary layer as well as the propagation of gravity |
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| 53 | waves, which were stimulated by |
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| 54 | the convection. However, in the stably stratified region the grid |
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| 55 | resolution has not necessarily to be as high as within the boundary |
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| 56 | layer. This can be obtained by a vertical stretching of the grid |
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| 57 | starting |
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| 58 | from 1200 m via <b>dz_stretch_level</b> = <i>1200.0 m.</i> This saves |
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| 59 | grid points and computing time. <font color="#800000">T</font><font color="#000000">he |
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| 60 | upper boundary of the model is located at (see </font><a href="chapter_4.1.html#dz_stretch_factor"><font color="#000000">dz_stretch_factor</font></a><font color="#000000">) |
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| 61 | … m (computed by the model)</font>.</p><p style="line-height: 100%;">Fast Fourier transformations are calculated using the Temperton-algorithm, which -on the IBM Regatta- is faster than the default system-specific algorithm (from IBM essl library).</p><p style="line-height: 100%;">The initial profiles for |
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| 62 | wind and temperature can be assigned via <b>initializing_actions</b> |
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| 63 | = <span style="font-style: italic;">'set_constant_profiles'</span>. |
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| 64 | The wind speed, constant with |
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| 65 | height, amounts to <b>ug_surface</b> = <b>vg_surface</b> = <i>0.0 m/s</i>. In order |
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| 66 | to allow for a fast onset of convection, a neutral stratified layer up |
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| 67 | to z |
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| 68 | = 800 m capped by an inversion with dtheta/dz = 1K/100 m is given: |
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| 69 | <b>pt_vertical_gradient</b> = <i>0.0, 1.0</i>, |
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| 70 | <b>pt_vertical_gradient_level</b> = <i>0.0, 800.0.</i> The surface |
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| 71 | temperature, which by default amounts to 300 K, provides the fixed |
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| 72 | point for the temperature profile (see <a href="chapter_4.1.html#pt_surface">pt_surface</a>). |
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| 73 | Convection is driven by a given, near-surface sensible heat flux via <b>surface_heatflux</b> |
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| 74 | = <i>0.1 K m/s.</i> A given surface sensible heta flux requires the |
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| 75 | bottom boundary condition for potential temperature to be <b>bc_pt_b</b> |
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| 76 | = |
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| 77 | <span style="font-style: italic;">'neumann'</span> . Thus |
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| 78 | all initialization parameters are determined. These can not be |
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| 79 | changed during the run (also not for restart runs). </p> |
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| 80 | <p style="line-height: 100%;">Now the run parameters (<tt><font style="font-size: 10pt;" size="2">&d3par</font></tt>) |
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| 81 | must be specified. To produce a quasi stationary boundary layer the |
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| 82 | simulated time should be at least one hour, i.e. <b>end_time</b> = <i>3600 |
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| 83 | s.</i> To stimulate convection, the initially homogeneous (zero) wind |
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| 84 | field must be disturbed (<b>create_disturbances</b> = <i>.T.</i>). |
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| 85 | These perturbations should be repeated in a temporal interval of |
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| 86 | <b>dt_disturb</b> = <i>150.0 s</i> until the energy of the |
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| 87 | perturbations exceeds the value <b>disturbance_energy_limit</b> = 0.<i>01 |
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| 88 | m<sup>2</sup>/s<sup>2</sup></i>. After each time step run time |
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| 89 | informations (e.g. size of the timestep, maximum velocities, etc.) are |
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| 90 | to be written to the local file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a> |
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| 91 | (<b>dt_run_control</b> = <i>0.0 s</i>).</p><p style="line-height: 100%;">Instantaneous cross section data of vertical velocity (<span style="font-style: italic;">w</span>) and potential temperature (<span style="font-style: italic;">pt</span>) are to be output for horizontal (<span style="font-style: italic;">xy</span>) and vertical (<span style="font-style: italic;">xz</span>) cross sections, and additionally, time averaged (<span style="font-style: italic;">av</span>) vertical cross section data are to be output for the vertical velocity: <span style="font-weight: bold;">data_output</span> = <span style="font-style: italic;">'w_xy'</span>, <span style="font-style: italic;">'w_xz'</span>, <span style="font-style: italic;">'w_xz_av'</span>, <span style="font-style: italic;">'pt_xy'</span>, <span style="font-style: italic;">'pt_xz'</span>. Output of instantaneous (time averaged) data is done after each 900 (1800)s: <span style="font-weight: bold;">dt_data_output</span> = <span style="font-style: italic;">900.0</span>, <span style="font-weight: bold;">dt_data_output_av</span> = <span style="font-style: italic;">1800.0</span>. The averaged data are time averaged over the last 900.0 s, where the temporal interval of data entering the average is 10 s: <span style="font-weight: bold;">averaging_interval</span> = <span style="font-style: italic;">900.0</span>, <span style="font-weight: bold;">dt_averaging_input</span> = <span style="font-style: italic;">10.0</span>. |
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| 92 | Horizontal cross sections are output for vertical levels with grid |
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| 93 | index k=2 and k=10, vertical cross sections are output for index j=20: <span style="font-weight: bold;">section_xy</span> = <span style="font-style: italic;">2</span>, <span style="font-style: italic;">10</span>, <span style="font-weight: bold;">section_xz</span> = <span style="font-style: italic;">20</span>. For runs on more than one processor, cross section data are collected and output on PE0: <span style="font-weight: bold;">data_output_2d_on_each_pe</span> = <span style="font-style: italic;">.F.</span>.</p><p style="line-height: 100%;">Output |
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| 94 | of vertical profiles is to be done after each 900 s. The profiles shall |
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| 95 | be temporally averaged<font color="#000000"> over the last <font color="#000000">600 </font>seconds, </font>whereby |
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| 96 | the temporal interval of the profiles entering the average has to be |
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| 97 | 10 s: <b>dt_dopr</b> = <i>900.0 s</i>, <b>averaging_interval_pr</b> = |
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| 98 | <i>600.0 s</i>, <b>dt_averaging_input_pr</b> = <i>10.0 s.</i> The temperature |
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| 99 | profile including the initial temperature profile (therefore <span style="font-style: italic;">'#pt'</span>), |
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| 100 | the subgrid scale, resolved and total vertical sensible heat flux as |
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| 101 | well as the variances of the vertical velocity and the potential |
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| 102 | temperature are to be output: <b>data_output_pr</b> = <span style="font-style: italic;">'#pt'</span><i>, 'w"pt”', |
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| 103 | 'w*pt*', 'wpt', 'w*2', 'pt*2'</i>.</p><p style="line-height: 100%;">If the data output format for graphic software <span style="font-weight: bold;">profil</span> is selected (see <a href="chapter_4.2.html#data_output_format">data_output_format</a>), the temperature |
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| 104 | profile and the individual variances are to be drawn into independent |
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| 105 | coordinate systems, and in contrast to this all heat flux profiles are to |
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| 106 | be |
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| 107 | drawn into the same system: <b>cross_profiles</b> = <span style="font-style: italic;">'pt'</span><i>, |
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| 108 | 'w"pt"w*pt*wpt', 'w*2', 'pt*2'</i>. The legend of the x |
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| 109 | axes of these systems is set to <b>cross_xtext</b>= <i>'pot. |
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| 110 | temperature in K', 'heat flux in K ms>->1', 'velocity variance |
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| 111 | in m>2s>->2', 'temperature variance in K>2'</i>. |
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| 112 | The profiles are to be drawn up to a height level of <b>z_max_do1d</b> |
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| 113 | = |
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| 114 | <i>1500.0 m</i>. </p> |
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| 115 | <p style="line-height: 100%;">Before starting the mo<font color="#000000">del |
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| 116 | on the parallel computer, the number of processing elements must be |
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| 117 | specified.</font> Since relatively few grid points are used for |
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| 118 | this run, choosing of e.g. 8 PEs is sufficient. By default, a 1d domain |
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| 119 | decomposition along x is used on the IBM-Regatta, which means that a |
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| 120 | virtual processor topology (grid) of 8*1 (x*y) is used. (<span style="font-weight: bold;">Note:</span> the user may adjust this |
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| 121 | default domain decomposition with the help of the parameters <a href="chapter_4.1.html#npex">npex</a> |
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| 122 | and <a href="chapter_4.1.html#npey">npey</a>). |
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| 123 | </p> |
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| 124 | <p style="line-height: 100%;">Provided that the parameters |
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| 125 | file described above are set within the file </p> |
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| 126 | <ul> |
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| 127 | <pre style="margin-bottom: 0.5cm; line-height: 100%;"><font style="font-size: 10pt;" size="2">~/palm/current_version/JOBS/example/INPUT/example_p3d</font></pre> |
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| 128 | </ul> |
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| 129 | <p style="line-height: 100%;">and that the conditions mentioned in the |
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| 130 | first sections of <a href="chapter_3.2.html">chapter |
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| 131 | 3.2</a> are met, the model run can be started with the command </p> |
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| 132 | <p style="line-height: 100%;"><font face="Cumberland, monospace"><font style="font-size: 10pt;" size="2">mrun |
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| 133 | -d example -h ibmh -K parallel -X 8 -T 8 -t 1800 -q cdev -r “d3# xy# xz# pr#”</font></font></p> |
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| 134 | <p style="line-height: 100%;">The output files will appear in the |
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| 135 | directories </p> |
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| 136 | <blockquote style="line-height: 100%;"><tt><font style="font-size: 10pt;" size="2">~/palm/current_version/JOBS/example/MONITORING</font></tt><font style="font-size: 10pt;" size="2"><br> |
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| 137 | </font><tt><font style="font-size: 10pt;" size="2">~/palm/current_version/JOBS/example/OUTPUT |
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| 138 | ,</font></tt></blockquote> |
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| 139 | <p style="line-height: 100%;">while the job protocol will appear in |
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| 140 | directory <font style="font-size: 10pt;" size="2"><font face="Cumberland, monospace">~/</font></font><tt><font style="font-size: 10pt;" size="2"><font face="Cumberland, monospace">job_queue</font></font></tt>. |
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| 141 | <br> |
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| 142 | </p> |
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| 143 | <hr> |
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| 144 | <p style="line-height: 100%;"><br> |
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| 145 | <font color="#000080"><font color="#000080"><a href="chapter_4.3.html"><font color="#000080"><img name="Grafik1" src="left.gif" align="bottom" border="2" height="32" width="32"></font></a><a href="index.html"><font color="#000080"><img name="Grafik2" src="up.gif" align="bottom" border="2" height="32" width="32"></font></a><a href="chapter_4.5.html"><font color="#000080"><img name="Grafik3" src="right.gif" align="bottom" border="2" height="32" width="32"></font></a></font></font></p> |
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| 146 | <p style="line-height: 100%;"><i>Last change: 13/04/06</i> (SR) |
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| 147 | <br> |
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| 148 | <br> |
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| 149 | </p> |
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| 150 | </body></html> |
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