Dear Giavaras, using values in the nodes is not a good idea, in particular since it depends on the actual element you use. In general, the use of node values is NOT recommended in deal.II. FEValues, FEFaceValues and FESubfaceValues are used for this.
There are two techniques I can recommend: 1. You integrate the normal velocity over the boundary faces using FEFaceValues very much like you would integrate the residual. 2. If the boundary conditions at the other parts of the boundary are known, you can use integration by parts and a volume integral to achieve the same goal. This yields better accuracy. Your very own Paul Houston has proposed this a while ago, if I remember correctly. Best, Guido Giavaras Alexandros wrote: > Hi everybody > I want to calculate the mean normal velocity component on a given > boundary after solving the stokes equations.I was wondering if this can > be done within the library or I have to find a vizualization package > doing that.I guess I have to find out the value of the desired component > on the global boundary node and weight it by the area surrounding that > node and then dividing by the area/length of the boundary.Does anyone > knows how this can be done in deal.II or to propose a way to do this? I > would like also to ask if there is a way to get the position of the > center of an element without having to calculate it?I am using a > taylor-hood element so I assume that a node exists already at this point > so is there a way of getting this information? > All the best > Alex > > This message has been checked for viruses but the contents of an attachment > may still contain software viruses, which could damage your computer system: > you are advised to perform your own checks. Email communications with the > University of Nottingham may be monitored as permitted by UK legislation. > > _______________________________________________ > Dealii mailing list > [email protected] > http://poisson.dealii.org/mailman/listinfo/dealii _______________________________________________ Dealii mailing list [email protected] http://poisson.dealii.org/mailman/listinfo/dealii
