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 sega April 19, 2008 13:14

dam break problem

I have some questions regarding the dam break problem in general.

I want to simulate the basic dam break problem.

I have data to compare from experiments (Martin & Moyce, 1951) and two numerical calculations (Griebel et al., 1995 and Ramaswamy, 1987).

The numerical soultions are both caluclatet for different Reynolds-Numbers. The Reynolds-Number for this problem is known as Re = H*sqrt(g*H) / nu Therin H equals the initial High of the water column, g gravity and nu the dynamic vicosity.

And now my first question. Which dynamic vicosity is meant to play a role in this problem. I suppose it must be the one for the water. So to compare the solutions obtained at a specific Re-Number I can calculate the appropriate nu and define it for the water-phase.

Now I have TWO problems left.

1. What Do I with the second nu? I don't think it's free to chose for the second phase. 2. What about the surface-tension? I have no idea about what to specify. Is it possible to derive it from the Re-Number? Or from the combination of phases?

 Mohamed April 20, 2008 17:51

Re: dam break problem

Hello ,

What kind of software are you using to simulate this case ?

What are the geometrical and numerical options choosen by the guys who have performed the numerical simulations related to your work ?

Best regards, Mohamed

 sega April 23, 2008 11:39

Re: dam break problem

I'm doing this with OpenFOAM. Currently I'm discussing solver related stuff in the appropriate forum.

My questions are rather basic and not concerning the solver itself.

The numerical simulation was done with Re=10 and a ratio of original high to original base-length of 2.

To compare the experiment: I think I will chose the transport Properties (nu,etc.) from the values for a real gas. I will chose the same properties for lengths as in the experiment.

To compare the numerical solution: I will chose the viscosity like the one for the real gas and will chose lengths to match the desired Re-number.

Does that sound appropriate?

Greetings.

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