# Schematic representation of TETA the wave propagation direction

**URL:** <https://opentelemac.org/forum/t/schematic-representation-of-teta-the-wave-propagation-direction/6623>\
**Category:** TOMAWAC\
**Created:** [September 24, 2021, 6:34pm UTC](https://opentelemac.org/forum/t/schematic-representation-of-teta-the-wave-propagation-direction/6623 "2021-09-24T18:34:08Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![user\_15624](https://opentelemac.org/forum/letter_avatar_proxy/v4/letter/u/5fc32e/32.png) [@user\_15624](https://opentelemac.org/forum/u/user_15624)\
**Post date:** [September 24, 2021, 6:34pm UTC](https://opentelemac.org/forum/t/schematic-representation-of-teta-the-wave-propagation-direction/6623/1 "2021-09-24T18:34:08Z")

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hello [name removed],

I am new in tomawac and in wave modeling in general.

I am trying to understand the first equation, but I got a problem to schematically represent [name removed] (wave propagation direction).

 ![first_equation_teta.png](https://opentelemac.org/uploads/default/original/2X/c/cf23cab03e8dabaf7998617657e85882c40cf008.png)

 ![first_equation_teta_suite.png](https://opentelemac.org/uploads/default/original/2X/d/df6dec4eb635821f7f9b005e43a58e51665ccdb5.png)

in my research I didn’t find a “scheme” representing this angle.

so My questions are

is Teta the angle of the tangent of a specific point on/of the wave.???

is teta an angle leading an axis parallel to the X axis (pointing in the same direction as the X axis) ??? by this way the angle teta is always (pi/2 or 90 degree). (I suppose we are in a [group removed] coordinate system)

[name removed]

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**Author:** ![user\_8473](https://opentelemac.org/forum/letter_avatar_proxy/v4/letter/u/8c91f0/32.png) [@user\_8473](https://opentelemac.org/forum/u/user_8473)\
**Post date:** [September 27, 2021, 1:27pm UTC](https://opentelemac.org/forum/t/schematic-representation-of-teta-the-wave-propagation-direction/6623/2 "2021-09-27T13:27:36Z")

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Hello

I am not sure to understand your question, you will find a scheme with [name removed] of the user documentation.

hope this helps

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**Author:** ![user\_15624](https://opentelemac.org/forum/letter_avatar_proxy/v4/letter/u/5fc32e/32.png) [@user\_15624](https://opentelemac.org/forum/u/user_15624)\
**Post date:** [September 30, 2021, 7:07am UTC](https://opentelemac.org/forum/t/schematic-representation-of-teta-the-wave-propagation-direction/6623/3 "2021-09-30T07:07:32Z")

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Hi

Thanks tfouquet,

Sorry if my question was not explicit/clear, I will try to make it more simple and clear…

Bests