# Discretization schemes of Comsol stationary solver

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 October 13, 2014, 10:10 Discretization schemes of Comsol stationary solver #1 Member   Sami Join Date: Nov 2012 Location: Cap Town, South Africa Posts: 87 Rep Power: 10 Hi, I would like to ask you how can I see what are the discretization schemes that a Comsol solver uses. This information is of great importance for any numerical study but Comsol doesn't show this ! Thank you in advance. PS: references are welcome Mehrez

 January 17, 2016, 09:57 #2 New Member   Join Date: Jan 2016 Posts: 2 Rep Power: 0 To display this section, click the Show button and select Discretization. It controls the discretization (the element types used in the finite element formulation). From the Discretization of fluids list select the element order for the velocity components and the pressure: P1+P1 (the default), P2+P1, or P3+P2. ! P2+P1 means that second order discretization for velocity field and first order discretization for pressure

 January 17, 2016, 10:18 A new problem with discretization with comsol #3 New Member   Join Date: Jan 2016 Posts: 2 Rep Power: 0 i have another problem with discretization with comsol: i use a SST scheme for a 3d geometry(sth like a tube with diameter of 30 mm and length of about 150 mm) every thing goes well for first order discretization type(P1+P1)and it converges up to 1e-5 with a relaxation factor about 0.5 BUT the problem begins when i want to solve the same problem with a second order discretization for the velocity field(P2+P1)! the software default discretization type is (P1+P1) and it has also mentioned that second order discretization for physics other than creeping flow will encounter with convergance problem and second order discretization will be suitable just for creeping flows. NOW i wanted to know whether a first order discretization will have enough accuracy or i have to deal the problem with second order discretization ??? Thanks in Advance!

 Tags comsol, discretization, scheme, solver, study