Merge pull request #225 from kent0/cyl-update

Update cylinder example with new run_rom and run_fom scripts

examples/cyl/README.md

@@ -4,13 +4,23 @@ A unit-diameter cylinder is centered at (0,0) in a box on [-2.5,17] x [-5,5].
 With unit inflow velocity at x=-2.5, the Reynolds number is given by Re =
 1/viscosity
 
-For the current case, we have Re=100.  The drag and lift coefficients are also
-computed by calls in userchk. To see the drag vs. time:
-
-grep drag logfile
+Run (with NekROM/bin and Nek5000/bin in $PATH and $MOR_DIR set to NekROM) `./run_fom` to generate the FOM fields and drag/lift data.
 
 ## ROM: Flow past a cylinder in 2D
 
+To obtain the ROM solution, run 
+
+```
+mkdir snaps && cp cyl0.f* snaps && ls snaps/*0.f* > file.list
+makerom cyl_rom
+nekbmpi cyl 1
+```
+
+```
+grep dragx logfile | sed 's/dragx//g' > rom.dragx.dat
+grep dragy logfile | sed 's/dragy//g' > rom.dragy.dat
+```
+
 The usr file for the ROM, cyl_rom.usr, mimics the FOM user file. In particular the rom_userchk subroutine is only a slight modification of the FOM userchk subroutine to accomodate variable name conflicts.
 
 To see the drag vs. time:

examples/cyl/cyl_rom.usr

@@ -52,6 +52,9 @@ c-----------------------------------------------------------------------
       include 'TOTAL'
       include 'MOR'
 
+      param(170) = -1
+      nsteps = 25 * 1e3 ! reduce to 100 CTUs
+
       call rom_update
 
       call exitt0
@@ -198,6 +201,11 @@ c-----------------------------------------------------------------------
       include 'TOTAL'
       include 'MOR'
 
+      if (ad_step.eq.0) then
+         isnap = 100 ! restart from 401 CTU snapshot
+         call copy(u,uk(1+(isnap-1)*(nb+1)),nb+1)
+      endif
+
       return
       end
 c-----------------------------------------------------------------------

examples/cyl/post.m

@@ -0,0 +1,28 @@
+% read fom and rom data
+fx=dlmread('fom.dragx.dat');
+fy=dlmread('fom.dragy.dat');
+rx=dlmread('rom.dragx.dat');
+ry=dlmread('rom.dragy.dat');
+
+% plot fom result:
+
+tstart=401;
+tend=500;
+
+figure;
+plot(fx(:,2),fx(:,3)); xlim([tstart tend]);
+title('Drag result');
+xlabel('Time');
+ylabel('Drag');
+
+% plot rom result:
+%figure;
+hold on
+rx(:,1)=rx(:,1)+tstart; % restart from t=400
+%plot(rx(:,1),rx(:,4)); xlim([400 500]);
+plot(rx(:,1),rx(:,4),'--');
+legend('FOM','ROM');
+%title('ROM drag result');
+xlabel('Time');
+ylabel('Drag');
+

examples/cyl/run_fom

@@ -0,0 +1,21 @@
+#!/bin/bash
+
+np=8 # number of processors to use for FOM calculation
+makerom cyl_fom # `makerom` can be replaced with `makenek`
+
+# generate mesh connectivity information
+genmap << EOF
+cyl
+0.1
+EOF
+
+echo 'running Nek5000 FOM calculation...'
+neklmpi cyl $np
+logfile=cyl.log.$np
+mkdir snaps && mv *cyl0.f* $logfile snaps && ls -r snaps/cyl0.f* > file.list
+
+# For the current case, we have Re=100. The drag and lift coefficients are also computed by calls in userchk. The following lines extract the data to .dat files
+grep dragx snaps/$logfile | sed 's/1dragx//g' > fom.dragx.dat
+grep dragy snaps/$logfile | sed 's/1dragy//g' > fom.dragy.dat
+
+echo 'done with FOM, exiting...'

examples/cyl/run_rom

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+makerom cyl_rom
+neklmpi cyl 1
+
+logfile=cyl.log.1
+
+# The detail computation of drag in the ROM is in Kento Kaneko An Augmented Basis Method for Reduced Order Models of Turbulent Flow. Ph.D. thesis (2022).
+grep dragx $logfile | sed 's/dragx//' > rom.dragx.dat
+grep dragy $logfile | sed 's/dragy//' > rom.dragy.dat
+