Surface Tension Initial Boundary Conditions
 

HI All,
Could someone please explain how initial boundary conditions for surface tension are defined in Handouts (Ansys Docs.).
dist = rdrop - sqrt((x - a[m])^2 +(y - b[m])^2,
delta = 0.01 >> (why only 0.01?? any calculations),
drop = 0.5*tanh(dist/delta)+0.5 >>> 0.5 (x coordinate value or fixed formula value) and 0.5 >> y coordinate value or fixed constant value ??

I have it in this form (below) and i dont know if it is done rightly or not, i doubt it though;

dist =sqrt((x- a [mm])^2 + (y- b [mm])^2 +( z+ c [mm])^2 )
and
liquid = step((rdrop-dist)/1 [mm]) But no Drop or Delta values calculated here.

Any suggestions Please, Thanks

The top set of equations simply blur the interface a little, whereas the bottom equations have a sharp interface. If you look at the resultign interface at the initial condition from both approaches you will see the blurring gives a smooth interface which converges nicely, but the sharp approach gives a jagged interface which can have convergence difficulties.

HI Glenn
 

Thanks, but in first set, what about delta value? I mean it is fixed 0.01??

delta is the blurring parameter. Bigger delta=bigger blur of the interface. Try changing it and see what happens.