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- - **OpenFOAM - 2nd order of discretization?**
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OpenFOAM - 2nd order of discretization?Hi all!
When FVM discretization is considered in OpenFOAM manuals, it is stated that linear variation of variable within CV represents 2nd order of accuracy: f(x) = f(x0) + (x-x0) * (grad f(x))|x=x0 But ussualy f(x) = f(x0) represents zero order of accuracy f(x) = f(x0) + (x-x0) * (grad f(x))|x=x0 is of the 1st order of accuracy .... and so on. The same way we get first order temporal derivative: dt(f)/dt = (f(t_n) - f(t_n-1)) / delta t using only first two terms in Taylor series, and is necessary to use third term to get second order approximation: dt(f)/dt = (3/2*f(t_n) - 2*f(t_n-1) - 1/2*f(t_n-2)) / delta t So what does actually mean "2nd order of accuracy" then? Thank you for your attention! Waiting for your comments. |

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