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Plotting Velocity Vectors - More Help [message #1165] Fri, 09 July 1993 04:08
gnaa38 is currently offline  gnaa38
Messages: 17
Registered: June 1993
Junior Member
Thanks to all the people who replied to my first posting but im still having
trouble trying to emulate my Fortran/Gino program with IDL/PVWave.
I will try to elaborate a bit. The original program is actually very simple.


I have an existing Fortran/Gino program that i am using to plot velocity
vectors.
I also have an evaluation copy of IDL & PV-Wave and am trying to rewrite the
original program.
Im not sure how to emulate part of my program however and wonder if
anyone can advise.
My vectors need arrows to show direction and velocity. I achieve this in
the Fortran program by scaling the vectors appropriately. This gives me
two sets of X and Y coordinates. The second set are calcaulated by
adding the scaling.
I then plot the vectors by moving to the first set of X and Y's and then
using the Gino Arrow command to draw an arrow to the second set of X and
Y's. This gives me the required direction, and the speed is represented
by the length of the arrow.
If this can be done in PV-Wave i'd be greatful to know how.

Here is the above mentioned Fortran Code.

DO 110 INDEX=1,N
CALL GRAMOV(X(INDEX),Y(INDEX))
C scale the velocity vectors so the longest is 10mm
X2=X(INDEX) + (U(INDEX) / VMAGMAX) * (10.0 * SCAL)
Y2=Y(INDEX) + (V(INDEX) / VMAGMAX) * (10.0 * SCAL)
CALL ARROW(X2,Y2,2,1)
110 CONTINUE

Here is a small sample of the data file.


************************************************************ ******************
Test: BVI P7491 UPPER
Approx. Tunnel Speed: 47 m/s
Vortex Strength: 6.7 m^2/s
Notes: Approximate starburst correction

************************************************************ ******************
X(mm) Y(mm) Ux(mm/s) Vy(mm/s)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~
-251.828500 -4.391304 1142.694000 100.049300
-241.181200 -8.326087 1027.821000 -74.817380
-242.475700 -1.760869 1129.224000 -589.092300
-218.775100 1.086959E-01 2868.505000 1196.826000
-212.658600 -5.434780E-01 4546.877000 -684.455100

Any help will be greatly appreciated.

--
Paul Porcelli
Dept of Aerospace Engineering
University of Glasgow
E-Mail: gnaa38@tigermoth.aero.gla.ac.uk
Tel: 041-339-8855 (x4345)
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