reduced.h
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Requires: iforce.h · curvature.h
Test cases (6): axi_rising_bubble, gravity, large-ns, rising, rt, stokes-ns
Examples (2): gaussian-ns, tangaroa
Reduced gravity
We re-express gravity in two-phase flows as an interfacial force as
with $p'= p - \rho\mathbf{g}\cdot\mathbf{x}$ the dynamic pressure and $\rho\mathbf{g}\cdot\mathbf{x}$ the hydrostatic pressure. The corresponding potential is
with $\mathbf{G}$ the gravity vector and $\mathbf{Z}$ an optional reference level.
coord G = {0.,0.,0.}, Z = {0.,0.,0.};We need the interfacial force module as well as some functions to compute the position of the interface.
#include "iforce.h" [api]
#include "curvature.h" [api]We overload the acceleration() event to add the contribution of gravity to the interfacial potential $\phi$.
If $\phi$ is already allocated, we add the contribution of gravity, otherwise we allocate a new field and set it to the contribution of gravity.
event acceleration (i++)
{
scalar phi = f.phi;
coord G1;
foreach_dimension()
G1.x = (rho2 - rho1)*G.x;
if (phi.i)
position (f, phi, G1, Z, add = true);
else {
phi = new scalar;
position (f, phi, G1, Z, add = false);
f.phi = phi;
}
}