TELEMAC-MASCARET Forum: turbulence model (1/1)

Welcome, Guest

TOPIC: turbulence model

turbulence model 9 years 4 months ago #17516

jbaills OFFLINE Fresh Boarder Posts: 23 Thank you received: 1	I use telemac2d for a calcul in a river or estuary("estuaire"). I wanted to know which turbulence model is the more interesting for this type of simulation. I did a first work with the model of smagorinski but I don't know if this model is good for a river. And which model is the fastest? Best regards, Julien
	The administrator has disabled public write access.

turbulence model 9 years 4 months ago #17542

jmhervouet	Hello, Given the probable size of your elements, you can start with a constant diffusion, of about 1 or 2 m2/s, it is certainly the fastest. Regards, Jean-Michel Hervouet
	The administrator has disabled public write access.

turbulence model 9 years 4 months ago #17552

jbaills OFFLINE Fresh Boarder Posts: 23 Thank you received: 1	Hello, I tried the constant diffusion with 1 m2/s but the simulation crashed after 25 sec but the same simulation worked with turbulence model 4 (smagorinsky model). The problem is with model 4, the simulation last a lot. I have no idea to explain this crash, maybe my boundary condition doesn't work with this model. Regards, Julien
	The administrator has disabled public write access.

turbulence model 9 years 4 months ago #17555

jmhervouet

Hello,

The problem with estuaries is to have a well posed problem, and if you prescribe the water elevation it may be unstable when the flow gets in, so you may want to try the Thompson boundary conditions. The choice of the turbulence model comes after, however check that the crash is not due to inf-sup condition, with checker-board oscillations of the free surface, in which case choosing : FREE SURFACE GRADIENT COMPATIBILITY : between 0.9 and 0. would help.

With best regards,

Jean-Michel Hervouet

The administrator has disabled public write access.