[kbaker]

Hello I am searching for a code can plot stream function in terms of u & v velocity components? May somebody guide me to a similar code?

Thanks
Khalid

[leflix]

Hi Kbaker,

Here is a piece of code in fortran to compute the stream function from the longitudinal U componnent of the velocity field.
Let me know if you need further details.

Leflix


C************************************************* *********
SUBROUTINE STREAM (U, DY, NI, NJ, PSI)
C************************************************* *********

IMPLICIT NONE

INTEGER NI,NJ, KX,KY, I, J
PARAMETER(KX=512,KY=512)

REAL*8 U, DY,PSI


DIMENSION U(0:KX,0:KY), PSI(0:KX,0:KY)

DO I=0,NI

PSI(I,0)=0.d0

DO J=1,NJ
PSI(I,J)= PSI(I,J-1) + U(I,J)*DY
END DO

END DO

RETURN
END

[kbaker]

Thanks Leflix for the reply. Actually I not looking for a fortran program I want to draw the stream function in Tecplot code? Do you have experience with it?

Khalid

Originally Posted by leflix

Hi Kbaker,

Here is a piece of code in fortran to compute the stream function from the longitudinal U componnent of the velocity field.
Let me know if you need further details.

Leflix


C************************************************* *********
SUBROUTINE STREAM (U, DY, NI, NJ, PSI)
C************************************************* *********

IMPLICIT NONE

INTEGER NI,NJ, KX,KY, I, J
PARAMETER(KX=512,KY=512)

REAL*8 U, DY,PSI


DIMENSION U(0:KX,0:KY), PSI(0:KX,0:KY)

DO I=0,NI

PSI(I,0)=0.d0

DO J=1,NJ
PSI(I,J)= PSI(I,J-1) + U(I,J)*DY
END DO

END DO

RETURN
END

[sbaffini]

That shoud be part of tecplot already... at least I recall it was. You should read the manual if that feature is not particularly immediate to reach.

[FMDenaro]

It is very easy, you have just to activate it in the menu and then click on a point in the field to have one streamline.

http://www.tecplot.com/blog/2014/10/...article-paths/

[leflix]

Ok ! Yes you have to upload your velocity field in 4 columns
x y Ux Uy
................
................

Then you activate streamtrace and as Filipo mentioned it click on a point you will have a streamline there. Yiu can also trace a line along the two opoosite corner of your domain and it will display sveral streamlines. Check out the documentation of tecplot.

Leflix

[kbaker]

Attachment 57592Thanks leflix and Filippo for the information. Leflix I already did a file with four coloums i.e. x y u v I saved it as general text file when I open it in Tecplot as a text and in order to activate streamtraces I need to do triangulation. The problem when I attempt to do 2D triangulation it give me error as the attached pict? so what the problem ?

Khalid

[leflix]

Is your grid structured or unstructured ?

[mariam.sara]

I have same problem

Originally Posted by leflix

Is your grid structured or unstructured ?

[kbaker]

Its structured grid I use meshing code to make the mesh and solve the problem using CFX code. My geometry is a sqaure cavity.

Originally Posted by leflix

Is your grid structured or unstructured ?

[FMDenaro]

Check first if the data are loaded correctly and show the grid to see if it appears structured

[leflix]

so you don't need to make a triangulation. Check how to format the data for structured grid. You have to loop on j and i , the number of nodes in j direction is NJ, and NI the number of nodes in the i direction.

write(1,*)'zone i=',NI,', j=', NJ,', F=POINT'

do j=1,NJ
do i=1,NI
write(1,*) Xc(i,j), Yc(i,j), U(I,J), V(I,J)
end do
end do

[FMDenaro]

leflix is correct, the first line is the header, the you can activate directly the streamtracer without triangulation

[kbaker]

I am really not sure about the type of mesh structured or not? I uploaded some picts for it?

Originally Posted by leflix

so you don't need to make a triangulation. Check how to format the data for structured grid. You have to loop on j and i , the number of nodes in j direction is NJ, and NI the number of nodes in the i direction.

write(1,*)'zone i=',NI,', j=', NJ,', F=POINT'

do j=1,NJ
do i=1,NI
write(1,*) Xc(i,j), Yc(i,j), U(I,J), V(I,J)
end do
end do

[leflix]

It is definetely a structured grid. You can access to every nodes with 2 indices i and j.

Leflix

[kbaker]

Dear Leflix As I think the part of program you sent it is in Fortran? right? I need to ask in order to apply it to the data I need to save the data in a file then call it by open? my question is do I need separate file for x,y,u and v or I store all of it in one file (as I stored it now see attached dat file which I arrange starting from left x,y,u,v)?
What part of program should be written before this statement:

write(1,*)'zone i=',NI,', j=', NJ,', F=POINT'

Originally Posted by leflix

It is definetely a structured grid. You can access to every nodes with 2 indices i and j.

Leflix

[leflix]

Hi Kbaker,

You should write all the data in the same file
x, y, U, V

just at the begining of the file write this:
VARIABLES= "X","Y", "U","V"
zone i= 100, j= 100 , F=POINT

assuming you have 100 grid nodes in i direction and 100 grid nodes in j direction. (this should be automatized when generatin the file in your code)

and then write
x,y, U,V as you did in your file.

name the file with .plt as extension rather than .txt so that Tecplot can recognise it and open it directly. Name it velocity.plt seems not bad.

[mariam.sara]

Is this code need to be programed in Fortran language?

[kbaker]

I am really confused about the program. Now I am started with writing a program to just reading the variable in a one matrix and print it as below:

IMPLICIT none
real X
integer i,j
DIMENSION X(5000,4)
open (unit = 1, file = "f:\velo.txt")
open(unit = 2 , file = "d:\fortran programing\res1.txt")
do i=1,4624
do j=1,4
Read(1,*) X(I,J)
enddo
enddo
do i=1,4624
write(2,*) (X(I,j),j=1,4)
enddo
stop
end



I just want to test the program validity in printing the variables but it tell me error: run time error F6501: Read(F:\velo.txt)
-end of file encountered

What the problem with my data? I attached the dat file?

Originally Posted by leflix

Hi Kbaker,

You should write all the data in the same file
x, y, U, V

just at the begining of the file write this:
VARIABLES= "X","Y", "U","V"
zone i= 100, j= 100 , F=POINT

assuming you have 100 grid nodes in i direction and 100 grid nodes in j direction. (this should be automatized when generatin the file in your code)

and then write
x,y, U,V as you did in your file.

name the file with .plt as extension rather than .txt so that Tecplot can recognise it and open it directly. Name it velocity.plt seems not bad.

[leflix]

First how many points do you have in x direction (i) and in y direction (j) ?