open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi forum,

The WAQTEL user manual (v8p2) says:
Dose it mean that coupling THERMIC and AED2 modules (WATER QUALITY PROCESS = 143) is invalid in T2D/T3D?

Regards,
Yunhao

Hello Yunhao,

Currently, AED2 module cannot be coupled with TELEMAC-2D.

Otherwise, the answer to your question is yes.

Coupling TELEMAC-3D with AED2 already includes a thermic exchanges, the same boundary condition for temperature at the free surface (see BORD3D subroutine) and quite the same volumetric source term for temperature (see the call in SOURCE_WAQ and the differences between CALCS3D_THERMICV and CALCS3D_AED2 subroutines; the only difference between the 2 subroutines for temperature is the light extinction coefficient given by Secchi depth or the user when coupling with THERMIC and computed by AED2 when coupling with this module).

Hope this helps,

Chi-Tuan

Hello Chi-Tuan,

Thanks for the explanation, I did some tests with THERMIC and AED2 as listed in the table below and found something strange regarding the water temperature modeling.

test 1	WATER QUALITY PROCESS = 11
test 2	WATER QUALITY PROCESS = 143 (initial Chl-a =44.42)
test 3	WATER QUALITY PROCESS = 143 (initial Chl-a =0.0)

The results were displayed in the attached picture and to my surprise, when coupled with AED2 the modeled surface water temperature was about 5°C higher than the result of TELEMAC-3D+THERMIC. Then in test3 the initial concentration of Chl-a was set to zero to exclude the potential impact of Chl-a on the light attenuation while the result remained almost the same. Do you have any idea why this happened? The tests were based on the waq3d_aed2_example with unchanged parameter setting.

Kind regards,
Yunhao

Hello Yunhao,

I thought what is written in the WAQTEL user manual and my explanations were clear, but it seems not to you.

With AED2, you can only user WATER QUALITY PROCESS = 13. So please do not try something else. In you case, you apply 2 times a computation of volumetric source term and that should explain your differences.

Anyway, if using this choice (= 13) and having differences of temperature between coupling with THERMIC module (= 11), this may be due to the extinction coefficient computed by AED2 that overwrites its equivalent value given to THERMIC.

Chi-Tuan