SPH modelling of viscous flows around cylinders from Re=10 to Re=1000

The SPH model in his weakly compressible formulation is applied to simulate viscous flows at low and intermediate Reynolds numbers (10 < Re < 1000) around a cylinder. It is well know in the literature that this kind of problem represents a challenge for the proposed numerical model. To overcome these drawbacks, here a proper ghost-fluid technique is proposed to deal with blunt bodies in viscous fluids. The no-slip condition on the body surface is implemented combining the technique proposed by Takeda et al. (1994) with the one proposed by De Leffe et al. (2011). The global loads on bodies are efficiently evaluated in the ghost fluid framework. Making use of a weakly compressible approach, additional issues have to be addressed for the sound waves. An in-depth validation of the model is performed comparing the numerical outcome with experiments data from the literature and other numerical references. In particular the solver is validated on the prediction of: drag and lift coefficients, wake length and shape and angle of separation (low Reynolds number), shedding frequency and minimum and maximum angles of separation (intermediate Reynolds number). The influence of the domain size is discussed in order to avoid wall side effects and at the same time to limit the computational costs. Convergence of the numerical solutions have been checked for both global and local quantities choosing appropriate Reynolds-cell number for the different test cases.