# Maximum still water level to calculate speedofsound using coefsound

Hi, Can someone let me know:

1) how the maximum still water level is calculated in each time step and regrading to which reference?

2) the default value is 0? this means it is equal to zero just for the initial condition? right?

Thanks

## Comments

1) how the maximum still water level is calculated in each time step and regrading to which reference?

This is only used at the beginning of the simulation to compute the speed of sound starting from the celerity of propagation of a dam-break

BUT it is not computed later at each time step...

2) the default value is 0? this means it is equal to zero just for the initial condition? right?

No, there is label auto=true after that that indicates that still water level is automatically computed.

If user wants to define a value should include the value instead of 0 and then auto=false

Dear Alex,

Thank you very much for your response. Just to make sure, when we have the hswl = 0; and auto=true, we have just one speed of sound for the entire simulation? For example, for dam break with 2 m water height, speed of sound = coefsound x

sqrt(g xhswl) = 20 x sqrt (20)? correct?Yes that it will be the speed of sound for the entire simulation.

More information about this (speed of sound and considering dam-break celerity as default) can be found in the book Violeau, 2012

Regards

Thank you.