CFD Online Logo CFD Online URL
Home > Forums > OpenFOAM Programming & Development

Generalized Navier Boundary Condition

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   December 3, 2013, 00:12
Default Generalized Navier Boundary Condition
New Member
Join Date: May 2012
Posts: 17
Rep Power: 7
boeleman is on a distinguished road
Hello Foamers,

I am trying to implement the Generalized Navier Boundary Condition

beta*U_slip + mu*dU/dn + gamma*(cos(theta_d) - cos(theta_e))*n_a*delta


beta: friction coefficient
mu: viscosity
n_w: normal of the wall
gamma: surface tension
theta_d: dynamic contact angle
theta_e: equilibrium contact angle
n_a: normal of fluid interface (alpha)
delta: contact line segment

I thought the partialSlip BC would be a good starting point, but I cannot figure out how to add a constant (surface tension part) to that BC. Has anyone experience writing a mixed/robin BC for a velocity field?


boeleman is offline   Reply With Quote

Old   December 4, 2013, 20:58
New Member
Join Date: May 2012
Posts: 17
Rep Power: 7
boeleman is on a distinguished road
Trying to understand the partialSlip BC, so I can figure out how to modify it, but having some trouble. The BC should be equal to:

v dot n = 0
(a*v+(1-a)*(grad(v) dot n)) dot t = 0

with n the surface normal and t a tangential vector. grad has to be dimensionless. This can be discretized as:

(a*v_w + (1-a)*(v_w - v_p)L/d) = 0

with _w the value at the wall, _p in the cell center, d the distance between the wall and the cell center, and L a unit length. Looking at the snGrad function I expect the equation:

snGrad = ((1-a)/(1-a+a*d/L) * (I-n^2) dot v_p - v_p)/d

However, the code reads:

snGrad = ((1-a) * (I-n^2) dot v_p - v_p)/d

and I cannot figure out why.
boeleman is offline   Reply With Quote


generalized navier bc, gnbc, mixed bc, robin bc

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Domain Imbalance HMR CFX 5 October 10, 2016 05:57
CFX fails to calculate a diffuser pipe flow shenying0710 CFX 7 March 26, 2013 05:13
Mixed/Robin boundary condition aaev OpenFOAM Bugs 2 December 15, 2011 15:03
Setting outlet Pressure boundary condition using CAFFA code Mukund Pondkule Main CFD Forum 0 March 16, 2011 04:23
How exactly the "pressure outlet" bdry condition compute properties on the boundary? yating9901 FLUENT 3 June 28, 2010 12:26

All times are GMT -4. The time now is 18:27.