Page 314 - Process Modelling and Simulation With Finite Element Methods

Modeling of Multi-Phase Flow Using the Level Set Method 301

smhs (a hyperbolic tangent) is a common smooth approximant to the Heaviside
function. smdelta, similarly, is a smooth approximant to the Dirac delta
function. The prefactor on the Gaussian is for normalization - the quadrature
over the real line must be unity. It is potentially the case that weak terms could
be used to define point forces along the zero level set of phi, but the smooth
approximants are easier to code. kappa is the major component of the curvature
defined in (8.3). rO is the expression of the density as in (8.10).

For subdomain specifications, select the mode form Mulitiphysics and then pull
down the Subdomain menu. Select Subdomain settings.

Subdomain Mode
Select Incompressible N-S from Multiphysics
Select the Coefficient tab
0 Set p =rO, 77 =nu
Set F, =sigma*kappa*smdelta*phix/sqrt(phixA2+phiyA2)
Set Fy =sigma*kappa*smdelta*phiy/sqrt(phixA2+phiyA2)+r0*gy

0 Click Stream line diffusion on
Select Init tab
Set u=O, v=O and p=O
Click Apply and then OK
Select ChEM: Convection and diffusion from Multiphysics
Select ‘phi’ tab
SetD =dadd

0 SetR =O,u=uandv=v
Click Stream line diffusion on
Select Init tab
Set phi = $(l = 0) , see (8.12).
Click Apply and then OK

Now pull down the Solve menu and select the Parameters option.

Solver Parameters
Select Time dependent solver
Select Timestepping tab
Enter in output times: 0:0.025:3
Select fldaspk Timestepping algorithm
Define tolerance limits to 0.01
Click Apply, OK and then Solve
0