http://www.channelflow.org/dokuwiki/ 2010-09-10T08:41:17-07:00 http://www.channelflow.org/dokuwiki/ http://www.channelflow.org/dokuwiki/lib/images/favicon.ico text/html 2010-03-04T17:35:58-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:continuefields?rev=1267752958&do=diff Quadratic extrapolation of FlowField u(mu) as function of parameter mu, where mu is one of Reynolds number, dP/dx, Lx, Lz, Lx/Lz, sqrt(Lx^2 + Lz^2), or the length between the starting (Lx,Lz) and a target value of (Lx,Lz). continuesoln : (ALPHA VERSION!) continue invariant solution of plane Couette flow in Reynolds number options : -r --restart … text/html 2010-02-02T07:55:09-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:continuesoln?rev=1265126109&do=diff continuesoln continues an equilibrium, traveling wave, or periodic orbit in a parameter μ. The parameter μ is one of Reynolds number, Lx, Lz, Lx/Lz, sqrt(Lx^2 + Lz^2), or dPdx. Continuation is done by a predictor-corrector method, using quadratic extrapolation in pseudo-arclength s along curves in the (μ,D) plane for prediction, and Newton-Krylov-hookstep search for correction. text/html 2009-02-13T08:45:53-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:couette?rev=1234543553&do=diff couette integrates plane Couette or channel flow from a given initial condition and save velocity fields to disk at a regular interval. (It should probably be called integrate; I might change it to that in the next release.) -T0 --T0 <real> default == 0 start time -T1 --T1 <real> default == 100 end time -dt --dt <real> default == 0.03125 timestep -dT --dT <real> … text/html 2010-02-02T07:55:09-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:field2ascii?rev=1265126109&do=diff convert a binary flowfield file (.ff) to an ascii data file (.asc) options -p --padding save full Nx x Ny x Nz grid rather eliminating padded modes -g --gridpoints write x.asc, y.asc, z.asc gridpoint files <fieldname> (trailing arg 2) flowfield input file <asciifile> (trailing arg 1) ascii output file text/html 2010-02-02T07:55:09-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:field2hdf5?rev=1265126109&do=diff convert a binary flowfield to HDF5 file format. -p --padding save full Nx x Ny x Nz grid rather eliminating padding <fieldname> (trailing arg 2) flowfield input file <hdf5file> (trailing arg 1) hdf5 output file text/html 2009-03-22T09:37:36-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:fieldprops?rev=1237739856&do=diff print out basic properties of a FlowField options : -g --geometry show geometrical properties -m --mean show mean properties -n --norm show norm properties -sp --spectral show spectral properties -sy --symmetry show symmetry pr… text/html 2009-06-08T06:40:21-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:findorbit?rev=1244468421&do=diff findorbit: Newton-Krylov-hookstep search for (relative) periodic orbit of plane Couette flow. Algorithm by . Note: this algorithm can take hours or days to run to completion. usage: findorbit [-orb|-eqb] [-rel] [-T maptime] [-opts] guess.ff main options: -eqb --equilibrium search for equilibrium or relative equilibrium (trav wave) -orb --periodicorbit search for periodic orbit or relative periodi… text/html 2010-03-04T17:37:53-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:findsoln?rev=1267753073&do=diff find an equilibrium, traveling wave, periodic orbit, or relative periodic orbit of plane Couette or channel flow, using a Newton-Krylov-hookstep search algorithm. -eqb --equilibrium search for equilibrium or relative equilibrium (trav wave) -orb --periodicorbit search for periodic orbit or relative periodic orbit -xrel --xrelative search over x phase s… text/html 2010-02-02T07:55:09-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:l2dist?rev=1265126109&do=diff compute the L2 Distance between two fields options -sx --shiftx shift by Lx/2 -sz --shiftz shift by Lz/2 <flowfield> (trailing arg 2) input field #1 <flowfield> (trailing arg 1) input field #2 text/html 2010-02-02T07:55:09-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:l2ip?rev=1265126109&do=diff compute the L2 inner product between two fields options -d --digits <int> default == 7 number of digits -n --normalize normalize by norms of each field <flowfield> (trailing arg 2) input field #1 <flowfield> (trailing arg 1) input field #2 text/html 2010-02-02T07:55:09-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:options?rev=1265126109&do=diff The channelflow utilities are stand-alone command-line programs that are run from the Unix shell. You can get brief built-in help information on each utility by running it with a -h or --help option. For example, running “couette --help” produces text/html 2009-03-02T11:13:52-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:poincare?rev=1236021232&do=diff Compute crossings of a Poincare section in a pre-computed trajectory. The Poincare condition is (u(t) - ueqb, e) == 0, i.e. the displacement from a given point ueqb is orthogonal to a direction e. The program checks for changes in sign in the inner product in the stored trajectory (with large dT, and when it finds one, goes back and reintegrates with small dt, and then does quadratic interpolation when the fine-scale trajectory recrosses the section. text/html 2009-07-08T08:02:50-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:randomfield?rev=1247065370&do=diff Create a velocity field with * random spectral coefficients that decay exponentially * zero divergence * Dirichlet boundary conditions at the walls options -Nx --Nx <int> # x gridpoints -Ny --Ny <int> # y gridpoints -Nz --Nz <int> # z gridpoints -a --alpha <real> default == 0 Lx = 2 pi/alpha -g --gamma <real> default == 0 … text/html 2009-02-11T09:10:56-07:00 http://www.channelflow.org/dokuwiki/doku.php/docs:utils:symmetryop?rev=1234372256&do=diff symmetryop: apply a symmetry operation to a given field options : -sn --sn <int> default == 0 apply s1, s2, or s3 symmetry (0 => use sx,sy,sz,ax,az,a) -sx --x-sign change u,x sign -sy --y-sign change v,y sign -sz --z-sign change w,z sign -ax --axshift <real> default == 0 translate x by ax*Lx -az --azshift <real> default == …