Thanks, now I clearly understand what's going on! Jaekwang
On Monday, August 14, 2017 at 3:08:18 PM UTC-5, Jaekwang Kim wrote: > > Hi, all > > I am little bit confused by weak form for advection problem written in > step-9 tutorial > > in the its tutorial, in the middle of the line, it says that... > > I am little bit unsure the red-marked form, > > From the whole boundary integral, we put inflow case, to the right hand > side, and remaining part on left-hand-side is cases other than inflow > condition > > so I thought, this should be.. > > > <https://lh3.googleusercontent.com/-_-hS916j4W8/WZICJB_jYWI/AAAAAAAABEU/scEwE0R6BlYkOd4_vFYaAm-8rLuEOdqoACLcBGAs/s1600/Screen%2BShot%2B2017-08-14%2Bat%2B2.59.36%2BPM.png> > > > the left hand side term is boundary that is not inflow case... > > I saw similar expression, in Dr. Bangerth video lecture 31, on hyperbolic > equation, here his weak form also marked 'not inflow boundary' remaining in > left hand side and inflow case, with boundary value description went to RHS > <https://lh3.googleusercontent.com/-cH5kYs776Is/WZICpHCSv8I/AAAAAAAABEc/_xxauCWctgQjlxdx61-e9PCBuYZkLJINwCLcBGAs/s1600/Screen%2BShot%2B2017-08-14%2Bat%2B3.04.56%2BPM.png> > > ..... I am not sure i am just confusing some of indication... .. > > > thanks ! > > > > > > > > > > This is a point we made in the introduction of step-3 > <http://dealii.org/developer/doxygen/deal.II/step_3.html>. There, we > argued that to avoid this very kind of problem, one should get in the habit > of always multiplying with test functions *from the left* instead of from > the right to obtain the correct matrix right away. In order to obtain the > form of the linear system that we need, it is therefore best to rewrite the > weak formulation to > > (vh+δβ⋅∇vh,β⋅∇uh)Ω*−(β⋅nvh,uh**)**∂**Ω**−*=(vh+δβ⋅∇vh,f)Ω−(β⋅nvh,g)∂Ω− > > and then to obtain > > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
