# Lack of understanding? Spatial OF Schemes

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 April 15, 2014, 09:38 Lack of understanding? Spatial OF Schemes #1 Senior Member   Join Date: Jan 2014 Posts: 179 Rep Power: 11 Hi guys, i just want to ask a simple question, I heard often that OF is 2nd order in spatial and time. Higher order in time: Possible, implementing Runge-Kutta Higher order spatial: If I have a look at the numerical schemes of OpenFoam on this side: http://openfoam.org/docs/user/fvSchemes.php For those terms is always a fourth order interpolation scheme existing: interpolationSchemes snGradSchemes gradSchemes Gradient divSchemes Divergence laplacianSchemes Laplacian This means that the reconstruction of the flux could be done by 4th order polynomials (bounded or unbounded) for all NS Eq Terms . So this must be 4th order in space, or do I miss something really important? Thanks to you In addition to that: How can I use the fourth order schemes in correct way? I got always the error that the fourth order schemes are unknown Code: ```gradSchemes { default none; grad(p) Gauss fourth; } divSchemes { default none; div(phi,U) Gauss fourth; } laplacianSchemes { default none; laplacian(nu,U) Gauss fourth; laplacian((1|A(U)),p) Gauss fourth; } interpolationSchemes { default none; interpolate(HbyA) cubicCorrection; } snGradSchemes { default fourth; } fluxRequired { default no; p ; }```

 April 30, 2014, 07:15 #2 Senior Member   Join Date: Jan 2014 Posts: 179 Rep Power: 11 no one can comment on that?