Flow past a circular cylinder Research Papers (original) (raw)
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In the present paper the study of the two-dimensional flow field past a circular cylinder for Reynolds number up to 5 · 10 5 is addressed. A Lagrangian particle method approach has been exploited and the simulations have been performed... more
In the present paper the study of the two-dimensional flow field past a circular cylinder for Reynolds number up to 5 · 10 5 is addressed. A Lagrangian particle method approach has been exploited and the simulations have been performed with high spatial resolutions in order to resolve all the main vortical scales. Long simulation time evolutions have been performed in order to get the vortex shedding dynamics as well as the Fourier analysis of the loads. The adopted numerical method allows to discuss both local (boundary layer and near wake dynamics) and global (far wake dynamics) aspects of the problem. The fundamental aspects related to the different identified flow states as well as the drag crisis mechanism are investigated.
Negative viscosity seems to be an impossible parameter for any thermodynamic system. But for some special boundary conditions the viscosity of a fluid has apparently become negative, like for secondary flow of a fluid or in a plasma flow... more
Negative viscosity seems to be an impossible parameter for any thermodynamic system. But for some special boundary conditions the viscosity of a fluid has apparently become negative, like for secondary flow of a fluid or in a plasma flow interacting with a dominant magnetic field. This work studied the effect of negative viscosity for a fluid flow over a cylinder. Four different viscosities are considered, in which the positive viscosities of Air and CO2 has been considered at 300 K temperature and their negative pair of viscosities are considered in this work. The results show a vast difference in the vortex formation and pattern. General incompressible Navier Stokes equation has been employed for the analysis. The thermodynamic feasibility, vortex formation, variation of X direction velocity, variation of the VA factor and variation of drag coefficient has been studied subsequently in this work. SimFlow CFD software has been used in this work, which uses the OpenFOAM solver.