open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi,
I have run the telemac3d/particles example. In the output .cas file, z coordinates seem to be sigma coordinates (they are in the range [0 1]): is it like this? If so, is there a way to have physical (true elevation) coordinates as an output?

I have checked the derive.f file: the sigma transform back conversion (lines 330-336) is written as

ETF = ETAFLO(IFLOT)
ZFLOT(IFLOT)=ZSTAR(ETF)+ SHZFLO(IFLOT)*(ZSTAR(ETF+1)-ZSTAR(ETF))

Shouldn't it be ZPLANE in place of ZSTAR in order to convert properly?

Hello Marco,

Can you explain more what you mean by "output .cas file". Is it the ASCII DROGUES FILE?

I have just run the telemac3d/particles example and looked at ASCII DROGUES FILE and there is obviously a bug when writing this file: y and z coordinates are exactly the same. Indeed, in TELEMAC3D subroutine when calling UTIMP_DROGUES, the 2nd YFLOT should be replaced by ZFLOT:

Change
CALL UTIMP_DROGUES( LT,AT,NPOIN2,NPOIN3,
& XFLOT%R,YFLOT%R,YFLOT%R,TAGFLO%I,CLSFLO%I,
& NFLOT,NFLOT_MAX,FLOPRD,DEJA_DROGUES_UTIMP,
& T3D_FILES(T3DFLO),T3D_FILES(T3DBLO), MARDAT,MARTIM )

to

CALL UTIMP_DROGUES( LT,AT,NPOIN2,NPOIN3,
& XFLOT%R,YFLOT%R,ZFLOT%R,TAGFLO%I,CLSFLO%I,
& NFLOT,NFLOT_MAX,FLOPRD,DEJA_DROGUES_UTIMP,
& T3D_FILES(T3DFLO),T3D_FILES(T3DBLO), MARDAT,MARTIM )

If you do not talk about ASCII DROGUES FILE, I do not understand your issue.

Hope this helps,

Chi-Tuan

Yes, I mean the ascii drogues file. In my case (using telemac3d v8p1r1) the z coordinates are not the same as the y coordinates: see the attached file t3d_particles_original.txt.
I couldn't find the lines you mention in telemac3d.f, I thought it was derive.f managing drogue advection, sorry!
I have tried modifying subroutine derive.f, putting SSIGMA=.FALSE. in place of line 242, and the result is t3d_particles_modified.txt which I have attached here. The z coordinates seem reasonable, but at this point I cannot be sure that they are correct. Also, with this change as you can see from comparing the files the x and y coordinates are modified too, though not dramatically...

Thank you!
Marco

Hello Marco,

Sorry, I ran the particles example with the trunk release and what I wrote you was introduced after the tag of v8p1. Anyway, you raised me a bug introduced by a recent new feature, that helps us.

I have to run the particle example with tagged releases to investigate, I do not have any on my personal computer. I keep in touch.

Chi-Tuan

Sure, I'd be glad to help if I can.