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Dear Users,

I hope somebody could point me into right direction. I am new to the tidal model. I am using version v6p3 in parallel. The tidal database is TPXO. For some reasons I cannot get any tidal results in r3d but I have some in r2d. Could it be because tpxo.f is located in source/telemac2d but not in telemac3d? I specified initial water depth as 900m (very simple bathymetry) but as per running results I get from 900m to 10m. Also velocity U is high as well up to 20m/s. I am definitely doing something wrong. I used validation case " tide" as example. I still have to learn a lot about tidal modelling as all my previous cases were on stratification only and not wave or tides were included. Also I had some problems with tpxo files but I think it is ok now. Please see attached cas, fortran and boundary condition file. Sorry for being a pain but any help would be much appreciated. Thanks a mil.

Kind Regards!

Violeta

Dear Users,

Please ignore my previous inquiry on velocities and water depth. My selafin file was wrong and did not read the water depth properly. It is fine now. But I still have a quick question on Initial Elevation. The Initial Conditions I have as Constant Elevation. The deepest area in my domain is around 70m. The predicted tides file starts with amplitude 0.9289. Maybe that what I have to enter as a initial elevation. Please advise. Thanks.

Kind Regards!

Violeta

Hello,

yes this is correct -- otherwise it would be such that you are trying to simulate a 1m wave / bore coming into your domain ...

Hope this helps,
Sébastien.

Thank you Sebastien. I also discovered another mistake in my cas file. Since I am using TPXO tidal database then I have to use Initial Conditions as TPXO SATELLITE ALTIMETRY. I am running it now, so hope this time it will be right, if not then I will be back:(. Sorry to be a pain. Thanks again.

Kind Regards!

Violeta

Hello,

Question for Violeta, Sébastien and Chi-Tuân: is there here an error that could be checked or secured automatically, e.g. if TPXO boundary conditions are used, initial elevation must be also TPXO, so we set it whatever does the user?

Regards,

JMH

Thank you Jean-Michel.

Looks like I cannot get tidal data on North Sea for full domain (to be able to plug in the data on the boundary line), on TPXO database I could get data for single point only and that is not enough. So I am afriad I cannot answer the question as per your previous post as I cannot get it working.

I see some posts and example on using JMJ database. I have been searching on internet to download it (maybe it is not an opensource?)but could not find it. Does it have any other name? Or maybe there is some other open source tidal database for Europe that I can use instead and Telemac accepts it. Thanks in advance.

Kind Regards!

Violeta

Dear Users,

Somehow I managed to get the TPXO tidal data file on full domain. I don't have experience on running tidal modal so it is my first attempt with some positive results but I am not sure if I got correct output. The water level seems to be fine but I have two points (on two nodes, far from each other, somewhere in domain) that produces high velocities.

My question is: Does the tidal data has to be specified at each node on the open boundary? For example, I have an open boundary with length 500km and mesh is 1km where tide comes from, so I am missing an understanding how the tidal data enters into domain, how the information is read on the boundary on Telemac3d. I saw a Tidal model simulation manual in french (unfortunately I cannot read in french, one more thing to learn in near future:) ) which has an example of Cas file if using TPXO, and that helped me a lot, but since I am getting two points of high velocity (on the boundary) in domain then I think that something is not right at the boundary. Please advise. Thanks in advance.

Kind Regards!

Violeta

Hello Violetta,

To use the harmonic constant database, you have to know and declare a geographic system to locate the liquid boundary nodes conditions.
It is highly advised to use a mesh generated with a plane projection, not latitude/longitude.

Have you read the TELEMAC-3D User manual for version 6.2? There are some paragraphs dealing with modelling tide in TELEMAC, and an English version exists.

Big values on liquid boundaries may come from location where there are tidal flats in the TPXO database. If these 2 nodes are not so far from the shoreline, it could be the reason why you have big values for velocities.
As told in a proceeding during the Telemac-Mascaret User Conference in 2012, it is advised to use the most refined solution coming from the Oregon State University when possible to prevent from a too coarse solution near the shoreline.

Hope this helps,

Chi-Tuan

Hello Violetta,

FYI, the JMJ database is provided in the 'tide' test case. You have to take the two files corresponding to the two keywords:
ASCII DATABASE FOR TIDE : bdd_tide-jmj.txt
TIDAL MODEL FILE : tid_tide-jmj.slf

Nevertheless, the extent of this model does not cover a large part of the North Sea.

Regards,

Chi-Tuan

Hello Jean-Michel,

I let people who want to model tide with the TPXO-like database to have the choice to use other initial conditions rather than the TPXO SATELLITE ALTIMETRY, even though these last ones should be the best choice.

Chi-Tuan