1st - 2nd order - convergence

antonio

Hi everybody, I'm running a simple 2D simulation. A cylinder (D=1 m) is placed on the ground (contact point in x=0, y=0). Air is entering the domain at 10 m/s. The domain is: [(x=-3 to 5), y=0 to 4]. Viscous model: Laminar.

I Run a simulation with the following scheme: [Pressure: Standard; P-V Coupling: SimpleC; Momentum: First Order Upwind] and the problem easily finds a convergence (1e-06).

If I change Momentum to [Second Order Upwind], the continuity residual shows an oscillatory behaviour at around 1e-04.

Do you have an idea what is this due to? Thank you very much,

antonio