BC on further limited region

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Author Message   Susanne Zibek (susanne) New member Username: susanne Post Number: 1 Registered: 12-2007 Posted on Thursday, December 27, 2007 - 12:42 pm:    Hello and Happy belated Christmas, I have a cylinder including a fluid with concentration u=0, on the bottom is a limited region 'bottom-pore' with influx J of another fluid natural(u)=J. The distribution of influx fluid within cylinder is driven by convection (velocity vx,y,z destribed by Navier-Stokes-equations) and diffusion. The timedependent result is an expected consistant concentrationgradent in the 'cylinder'. Then I extend the model with two further limited regions 'blob1','blob2' as sensors. I'm interessted in the surface integrals over time within this area. My problem is now that the regions 'blob1','blob2' do influence velocity and therefor concentrationgradient in the cylinder- this result is unexpected. I guess the boundary conditions in 'blob1','blob2' are wrong. I hope for a good suggestion. Thanx Susan Forum.pde (7.7 k) NS_transfer_3D_04.dat (3673.4 k)   Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 1038 Registered: 06-2003 Posted on Friday, December 28, 2007 - 05:52 pm:    I don't see any sign of the "blobs" affecting the flow. I put a plot of U on the bottom surface, and it looks like this: