[FLASH-USERS] How to force the velocity to be zero in simulation

[Gabriel Rigon]

Hi,

You might want to use the BDRY_VAR variable to define your solid. This 
variable can be assigned to every cell, positive value correspond to 
rigid body.
You will need to add for each time step a loop to check the conditions 
inside the rigid body and change the BDRY_VAR to negative value when it 
should change state (melting / boiling point).

Best regards,
G. Rigon

Le 04/09/2019 à 11:05, leizhuray a écrit :
> According to you simulation results,  expansion just occurs in the 
> left corner. This may be due to laser heating in LaserSlab. You can 
> check the 'depo' in chk data file to make sure about this.
>
>
> 发自网易邮箱大师
> On 9/4/2019 16:45，Zhang Daoyuan<zdy0903 at stu.xjtu.edu.cn> 
> <mailto:zdy0903 at stu.xjtu.edu.cn> wrote：
>
>     Hi all!
>
>       For a lot of simulations, if I want to initialize it from room
>     temperature (300K) like LaserSlab, I find that there is thermal
>     expansion at the interface between the solid slab and low density
>     gas at room temperature. This is beacause the material strengh is
>     not taken into account in the simulation so that the pressure for
>     solid slab at 300K is very high. This is not physical in reality.
>
>       It can be shown on the picture below, this is density and
>     velocity at y direction distribution for LaserSlab simulation at
>     1e-11 s.
>
>
>
>
>       To solve this problem, an idea is that keep the solid at
>     stationary till the melting or boilding point. I need to force the
>     velocity to be zero in the simulation. In FLASH, how can I do that?
>
>       This is important to my simulation because my simulation is
>     about Z pinch which use a current to heat solid. Before the solid
>     reach to the melting teperature, the current will heat the
>     unphysical thermal expanded materials to very high temperature.
>
>       Thanks a lot!
>
>
>
>     Yours
>
>     Zhang
>
>
>
-- 
Gabriel Rigon
--
Ph.D. student
Laboratoire LULI
Ecole Polytechnique
91128 Palaiseau cedex, France
Tél : +33-(0)1 69 33 54 21

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