# Barrier obstacle in TELEMAC-3D with tracer

**URL:** <https://opentelemac.org/forum/t/barrier-obstacle-in-telemac-3d-with-tracer/8151>\
**Category:** TELEMAC-3D\
**Created:** [July 17, 2026, 7:53am UTC](https://opentelemac.org/forum/t/barrier-obstacle-in-telemac-3d-with-tracer/8151 "2026-07-17T07:53:41Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![user\_16110](https://opentelemac.org/forum/letter_avatar_proxy/v4/letter/u/dfb087/32.png) [@user\_16110](https://opentelemac.org/forum/u/user_16110)\
**Post date:** [July 17, 2026, 7:53am UTC](https://opentelemac.org/forum/t/barrier-obstacle-in-telemac-3d-with-tracer/8151/1 "2026-07-17T07:53:41Z")

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Dear [name removed],

I am testing the use of a porous barrier obstacle in TELEMAC-3D (v9.1) to represent a wooden pier. The model runs fine without tracers, but when I activate salinity, it crashes at the first iteration with:

================================================================================

ITERATION 0 TIME 0 D 0 H 0 MN 0.0000 S ( 0.0000 S)

================================================================================

APPEL DE PRERES\_TELEMAC3D

RETOUR DE PRERES\_TELEMAC3D

APPEL DE BIEF\_DESIMP

RETOUR DE BIEF DESIMP

APPEL DE BIEF\_DESIMP POUR 2D

RETOUR DE BIEF\_DESIMP POUR 2D

* * *

```
            MASS BALANCE

```

INITIAL VOLUME OF WATER IN THE DOMAIN : \<US\_SSN\>.52115595

PREMIER APPEL DE SOURCES\_SINKS

RETOUR DE SOURCES\_SINKS

PREMIER APPEL DE PREADV

OM4141 (BIEF): OFF-DIAGONAL STORAGE 2

```
            NOT IMPLEMENTED

            WITH OPERATION M=MSK(M)

```

The manual states that masking is not available in 3D and barriers cannot be used, suggesting obstacles must be represented as a hole in the mesh (which is not the best way to schematize a porous structure).

Could you please confirm:

- Are barrier obstacles not supported in TELEMAC-3D when tracers are used?

- Is this error directly related to that limitation?

Thank you for your help.

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<div class="post-metadata">

**Author:** ![user\_438](https://opentelemac.org/forum/letter_avatar_proxy/v4/letter/u/c77e96/32.png) [@user\_438](https://opentelemac.org/forum/u/user_438)\
**Post date:** [August 2, 2026, 5:39pm UTC](https://opentelemac.org/forum/t/barrier-obstacle-in-telemac-3d-with-tracer/8151/2 "2026-08-02T17:39:43Z")

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Hello,

I am not the specialist of this feature (obstacles) but indeed in TELEMAC-3D, porosity is not available and masking does not work for some features (including distributive schemes). I am surprised that it works without tracers (but are the results really good? Do you use e.g. characteristics). Anyway, if it is recommended not to use in the user manual, I would not try if I were you.

Hope this helps,

[name removed]

---

<div class="post-metadata">

**Author:** ![user\_16110](https://opentelemac.org/forum/letter_avatar_proxy/v4/letter/u/dfb087/32.png) [@user\_16110](https://opentelemac.org/forum/u/user_16110)\
**Post date:** [August 25, 2026, 2:21pm UTC](https://opentelemac.org/forum/t/barrier-obstacle-in-telemac-3d-with-tracer/8151/3 "2026-08-25T14:21:39Z")

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Hello [name removed],

Thanks for your reply.

Indeed, introducing the barrier obstacle affects the velocity field of the neighbouring elements. I’m not sure whether the resulting changes are good or bad, as I don’t have any measurement stations very close to the barrier structure. However, as you recommended, I will not use it in my project and will wait for the full implementation of this feature in future Telemac3D releases.

[name removed]