Implemented rescaling of velocity for decayling isotropic turbulence …

…runs.

The line in the input file that deals with rescales contains two numbers: TRESCALE (when to rescale) and NRESCALE (how many times to rescale).  The rescaling happens at times TRESCALE*1, TRESCALE*2, ..., TRESCALE*NRESCALE.

Rescaling means that the Fourier components of velocity are multipled in such a way that the energy spectrum takes the shape prescribed in the input file by the variables ips_type and peak_wavenum.

00_example.in

@@ -10,7 +10,7 @@ INPUT FILE FOR THE SPECTRAL CODE WITH SCALARS   (example for v.1.0.0)
 500		IWRITE4  how often to write real*4 binary files
 ----------------------------------------------------------------------
 10.0		TMAX     the maximum simulation time
-1000.0          TRESCALE time when to rescale the velocity (definct)
+1.0 3           TRESCALE, NRESCALE  rescale time and # of rescales
 0.0             TSCALAR  time when to start moving scalars in the flow
 ----------------------------------------------------------------------
 1               ITYPV    flow type: 0=decay, 1=forced

Makefile

@@ -67,6 +67,7 @@ OBJ     = main.o\
 	restart_io.o\
 	rhs_velocity.o\
 	rhs_scalars.o\
+	velocity_rescale.o\
 	write_tmp4.o
 
 

m_parameters.f90

@@ -2,7 +2,7 @@
 ! M_PARAMETERS - module for all parameters in the calculation: 
 !                such as array dimensions, reynolds numbers, switches/flags etc.
 !
-! Time-stamp: <2009-04-21 09:21:30 (chumakov)>
+! Time-stamp: <2009-04-30 12:07:52 (chumakov)>
 ! Time-stamp: <2008-11-20 17:27:59 MST (vladimirova)>
 !================================================================================
 
@@ -29,6 +29,9 @@ module m_parameters
 
   real*8  :: TMAX, TRESCALE, TSCALAR, RE, nu, dt
 
+  ! now many times to rescale teh velocities
+  integer :: NRESCALE
+
   integer :: flow_type
 
   logical :: variable_dt
@@ -238,8 +241,8 @@ subroutine read_input_file
     read(in,*,ERR=9000,END=9000) TMAX
     write(out,*) 'TMAX     =',TMAX  
 
-    read(in,*,ERR=9000,END=9000) TRESCALE
-    write(out,*) 'TRESCALE =',TRESCALE
+    read(in,*,ERR=8000,END=9000) TRESCALE, NRESCALE
+100 write(out,*) 'TRESCALE, NRESCALE =',TRESCALE, NRESCALE
 
     read(in,*,ERR=9000,END=9000) TSCALAR
     write(out,*) 'TSCALAR  =',TSCALAR
@@ -479,6 +482,18 @@ subroutine read_input_file
     end if
 
     return
+
+!--------------------------------------------------------------------------------
+!  ERROR PROCESSING
+!--------------------------------------------------------------------------------
+
+8000 continue
+    NRESCALE = 0
+    if (TRESCALE.gt.zip) NRESCALE = 1
+    write(out,*) "*** NRESCALE IS AUTOMATICALLY ASSIGNED to be ONE"
+    call flush(out)
+    goto 100
+
 9000 continue
     write(out,*)'An error was encountered while reading input file'
     call flush(out)

main.f90

@@ -101,6 +101,17 @@ program x_code
 !--------------------------------------------------------------------------------
      hydro: if (task.eq.'hydro') then
 
+        ! taking care of rescaling
+        ! if the time just was divisible by TRESCALE
+        if (floor((time-dt)/TRESCALE) .lt. floor(time/TRESCALE)) then 
+           ! ...and if we haven't rescaled NRESCALE times
+           if (floor(time/TRESCALE) .le. NRESCALE) then
+              write(out,*) "MAIN: Rescaling velocities"
+              call flush(out)
+              call velocity_rescale
+           end if
+        end if
+
         ! RHS for scalars
         call rhs_scalars
 !!$        write(out,*) "done with rhs_scalars"
@@ -214,7 +225,7 @@ program x_code
 !  requirements on the wrk array sizes in the particle interpolation routines.
 !--------------------------------------------------------------------------------
      particles: if (task.eq.'parts') then
-        
+
         call fields_to_parts
 
         if (int_particles) then
@@ -251,7 +262,12 @@ program x_code
         if (myid_world.eq.0) call m_timing_check
         count = 1
         call MPI_BCAST(cpu_min_total,count,MPI_INTEGER4,0,MPI_COMM_WORLD,mpi_err)
+
         ! allowing 5 extra minutes for writing restart file
+        ! note that for large-scale calculations (e.g. 1024^3)
+        ! the restart writing time can be long (up to 20 minutes or so).
+        ! this should be taken care of in the job submission script
+        ! via file job_parameters.txt
         if (cpu_min_total+5 .gt. job_runlimit) call my_exit(2)
 
         ! user termination.  If the file "stop" is in the directory, stop