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fixed defs for adap time step namelist vars in README.namelist (#2158)
TYPE: text only KEYWORDS: README.namelist, adaptive time step SOURCE: internal DESCRIPTION OF CHANGES: Problem: Definitions for a few adaptive time step-relative variables in README.namelist weren't comprehensible. Solution: Modified the wording to make more sense LIST OF MODIFIED FILES: M run/README.namelist
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run/README.namelist

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Original file line numberDiff line numberDiff line change
@@ -405,20 +405,23 @@ Namelist variables for controlling the adaptive time step option:
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use_adaptive_time_step = .false. ! T/F use adaptive time stepping.
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step_to_output_time = .true. ! if adaptive time stepping, T/F modify the
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time steps so that the exact history time is reached
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target_cfl(max_dom) = 1.2,1.2 ! vertical and horizontal CFL <= to this value implies
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no reason to reduce the time step, and to increase it
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target_hcfl(max_dom) = .84,.84 ! horizontal CFL <= to this value implies
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max_step_increase_pct(max_dom) = 5,51 ! percentage of previous time step to increase, if the
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target_cfl(max_dom) = 1.2,1.2 ! if vertical CFL is <= to this value, it means there
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is no reason to reduce the time step, and therefore
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time step is increased
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target_hcfl(max_dom) = .84,.84 ! if horizontal CFL <= to this value, it suggests no
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need to reduce time step, and therefore time step
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is increased
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max_step_increase_pct(max_dom) = 5,51 ! increase percentage for the previous time step, if the
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max(vert cfl, horiz cfl) <= target_cfl, then the time
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will increase by max_step_increase_pct. Use something
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large for nests (51% suggested)
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starting_time_step(max_dom) = -1,-1 ! flag = -1 implies use 4*dx (defined in start_em),
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will increase by this percentage; use something
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much larger for nests (51% suggested, i.e., = 5, 51, 51)
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starting_time_step(max_dom) = -1,-1 ! flag = -1 sets time step to 4*dx (defined in start_em),
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starting_time_step = 100 means the starting time step
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for the coarse grid is 100 s
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max_time_step(max_dom) = -1,-1 ! flag = -1 implies max time step is 8*dx,
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max_time_step(max_dom) = -1,-1 ! flag = -1 sets the max time step to 8*dx,
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max_time_step = 100 means that the time step will not
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exceed 100 s
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min_time_step(max_dom) = -1,-1 ! flag = -1 implies max time step is 3*dx,
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min_time_step(max_dom) = -1,-1 ! flag = -1 sets max time step to 3*dx,
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min_time_step = 100 means that the time step will not
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be less than 100 s
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adaptation_domain = 1 ! default, all fine grid domains adaptive dt driven by coarse-grid

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