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TOPIC: Water depth difference between Mascaret and Telemac

Water depth difference between Mascaret and Telemac 10 years 6 months ago #13098

  • special_20
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Hello all,

I use two superposed models (1D and 2D models) on a given area. By using the mesh of the 2D model I modified the geometry file of the 1D model so that both models have the same bathymetry on this area.

The free surface levels computed with Mascaret are used as free surface downstream boundary conditions for the 2D model and the discharges computed with Mascaret are used as upstream boundary conditions for the 2D model.

The problem is that the water depth computed with Mascaret at a given cross section (Z(10)-ZREF(10)) is not the same as the mean water depth computed with Telemac on the same cross section (mean of H%R on the cross section) ... The difference is almost constant and about 3 meters :sick:

Do you know where this difference originate from ? Is there some parameter to set ?

More, even though I'm not in the Mascaret forum do you know how is computed the ZREF variable in Mascaret ?

Thanks for your answers ;)
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Water depth difference between Mascaret and Telemac 10 years 6 months ago #13099

  • jmhervouet
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Hello,

Be aware that Mascaret will have friction on all the perimeter of the cross section, whereas with Telemac-2D you will get only friction on the bottom, unless you specify friction on the lateral boundaries. This is a difference that may require different coefficients for calibration, but 3 m seems a lot...,

JMH
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Water depth difference between Mascaret and Telemac 10 years 6 months ago #13111

  • special_20
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Hello,

I just understood what the problem is : it comes from my way to compute the depth with the 2D model. As I said before I compute the depth with Telemac as the mean depth on the cross section whereas I compute the depth with Mascaret as the difference Z-ZREF. But ZREF is not the mean of the elevation of the cross section this is the minimum elevation of the cross section. Hence if your bottom topography is not flat there may have a huge difference between those two methods...
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