S = vec2scal(V) returns scalar field(s) S given by the norm of the
vector field(s) V. The vector field(s) V can be obtained from loadvec.
The resulting scalar field(s) S can be displayed using showf.
S = vec2scal(V,MODE) specifies the conversion MODE:
norm norm (ux^2 + uy^2)^(1/2); by default.
ux, uy x or y component of the vector field
en, ken kinetic energy, norm^2 / 2
curl (or rot) curl (vorticity field)
absrot absolute value of the curl
div 2D divergence (dux/dx + duy/dy)
ens enstrophy (=square of vorticity / 2)
rad, deg velocity angle (tan(angle)=vy/vx), in rad or deg
strain norm of the strain rate, sqrt(s1^2 + s2^2),
where s1 and s2 are the 2D strain eigenvalues.
q Q-criterion, Q = (enstrophy - strain^2)/2
eps squared strain rate, s1^2 + s2^2
duxdx, duxdy, duydx, duydy spatial derivatives (du_i / dx_j)
txx, tyy, txy 3 components of the Reynolds stress tensor (u_i u_j)
(Careful: the average is NOT subtracted, and the
usual minus (-) sign is NOT included here)
smin minimum eigenvalue
real, imag extracts the real part or the imaginary part
Adding '-' (minus sign) before MODE (e.g., '-rot') inverts the result.
The resulting scalar field S contains the following fields:
x,y: vectors containing the X and Y coordinates
w: matrix of scalar elements
namex, unitx, namey, unity: strings for the name and unit of coord
namew, unitw: strings for the name and unit of the matrix w
name: name of the VEC file from which originates V
setname: name of the current directory
history: Remind from which command S has been obtained
The scalar fields built from derivatives (e.g., rot, div, ens etc.)
are computed from 2nd-order centered differences.
Specify 'rot1', 'div1' etc. to use 1st-order finite differences (in
this case, the resulting field is decreased by 1 unit, and the x and y
coordinates are interpolated).
S = vec2scal(FILE) is a shortcut for S = vec2scal(loadvec(FILE)).
By default, vectors with a zero component are considered as erroneous,
and are not used for the computation of the derivative fields (rot,
div, eps, duxdx, ...). If however you want to keep them in the
computation, specify vec2scal(V,MODE,'keepzero').
vec2scal(...), without output argument, shows the result with showf.
Examples
showf(vec2scal(v,'div'));
showf(vec2scal(filterf('*.vc7',2),'rot'));
stat_rot = statf(vec2scal(v,'rot'));
vec2scal *.vc7 ken
See Also
showf, gradientf, operf.
Published output in the Help browser
showdemo vec2scal