2019-05 - Modeling turbulence (2D)

Qualitative comparison of different turbulence models in jet flow is simulated by OpenFOAM. Four turbulence models found in OpenFOAM are compared: (i) kOmegaSST (ii) kOmegaSSTSAS (iii) kOmegaSSTDES (iv) RNGkEpsilon Passive scalar transport of substance “s“ is also simulated and presented in the animation. The value of 1 is assigned at inlet. Due to high inlet velocity, there is large velocity gradient at inlet and eddies would form due to Kelvin-Helmholtz instability. The eddies grow into bigger and bigger ones and the flow becomes chaotic. From appearance of the flow, turbulence modelled by “kOmegaSSTDES“ and “RNGkEpsilon“ looks similar. For “kOmegaSSTSAS, the eddies are weaker. For “kOmegaSST“, no eddy could be seen and there is the least dispersion of the substance. Remark: This simulation is in 2D and is strictly speaking incorrect in the sense that eddies are 3D in nature. Nevertheless, this animation might still give some feeling of how turbulence is modelled by different turbulence models.