[liangsun]

Dear All,

I am running the 'solitary' case in 'tutorials' of waves2Foam. But I am not sure that how to calculate the 'celerityFactor' in GABCSettings. Does anyone have more ideas? Thank you.

Example:

inletCoeffs
{
waveType chappelear1962;

x0 (-10 0 0);

height 0.15;
depth 0.50125;
direction (1 0 0);

GABCSettings
{
preProcessMethod constantDepth;
celerityFactor 1.11;
}
}

[ngj]

Dear Liang,


The celerity factor reflects the propagation speed of the wave to absorb, while my experience is that it matters less, what it is for wave generation. Consequently, I would run a few 2DV cases, where the performance of absorption of any internal reflection and/or propagation out of the down-wave boundary is checked.



The celerity factor in case of constantDepth is a factor on sqrt(gh) with h being still water depth at the boundary. For solitary waves, propagation speed exceeds sqrt(gh) (see e.g. the Boussinesq solution to solitary waves), so the celerity factor exceeds one (1). The celerity factor depends on the ratio of wave-height-to-water-depth.


I hope that you will find the GABC useful.



Kind regards


Niels

[liangsun]

Originally Posted by ngj

Dear Liang,


The celerity factor reflects the propagation speed of the wave to absorb, while my experience is that it matters less, what it is for wave generation. Consequently, I would run a few 2DV cases, where the performance of absorption of any internal reflection and/or propagation out of the down-wave boundary is checked.



The celerity factor in case of constantDepth is a factor on sqrt(gh) with h being still water depth at the boundary. For solitary waves, propagation speed exceeds sqrt(gh) (see e.g. the Boussinesq solution to solitary waves), so the celerity factor exceeds one (1). The celerity factor depends on the ratio of wave-height-to-water-depth.


I hope that you will find the GABC useful.



Kind regards


Niels

Dear Niels,

Thank you for the answer. By my calculation, celerity of solitary wave with height=0.15 and depth=0.50125 is 2.527169, which is different from the value 1.11 in tutorial.

I find the GABC is very useful in my research.

Kind regards

Liang

[ngj]

Dear Liang,


The celerity factor is nondimensional; please refer to the source code. In your specific case, it is



2.527169 [m/s] / sqrt(g 0.50125 [m]) = 1.1397 [-]



Kind regards


Niels

[liangsun]

Dear Niels,

Got it. Thank you for the reply.

Kind regards

Liang