Numerical analysis of flow around cylinder in critical and subcritical regime

The flow around cylinder open the path for studying more complex shape bodies like the ship’s hulls. The hydrodynamic properties of the ship’s hulls can be decomposed as combinations of the flow properties of simpler bodies like flat plates, cylinders, ellipses, spheres and ellipsoids. The aim of this study is to describe the flow around a cylinder based on simulations with platforms like Comsol and Ansys that further can be compared with experimental and analytical results. The drag force caused by the flow around cylinders can be combined with the drag force of simple elements like flat plates, ellipses in order to correlate with the drag force of a specific hull of ship. Cylinder is a case that offers with its simplicity the possibility to check the results in all three ways: analytical, computational and experimental. An exhaustive analysis of this shape offers a beginning path for generalizing the external flows like the application of the superposition theory for complex geometries.

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Numerical Analysis of Flow Around a Cylinder in Critical and Subcritical Regime

Sustainability ◽

10.3390/su13042048 ◽

2021 ◽

Vol 13 (4) ◽

pp. 2048

Author(s):

Ivan Kološ ◽

Vladimíra Michalcová ◽

Lenka Lausová

Keyword(s):

Numerical Analysis ◽

Physical Phenomenon ◽

Pressure Coefficient ◽

Reynolds Numbers ◽

Critical Regime ◽

Stream Velocity ◽

Flow Around A Cylinder ◽

Subcritical Regime ◽

Simple Geometry ◽

Les Model

Modeling the wind flow around cylindrical buildings is one of the problems within urban physics. Despite the simple geometry of the cylinder, it is an interesting physical phenomenon. Partial knowledge of flow field properties can be found in the literature, but in terms of their use for practical tasks, the data are still incomplete. The authors performed a numerical analysis of the flow around the smooth cylinder in the subcritical and critical regime for Reynolds numbers in the range of Re = 2.3 × 103 to 4 × 105. Turbulent flow was solved using LES model and the numerical solution was compared with available data from experiments or standard. Analysis of the mean stream velocity showed the elongation of the core of the wake with decreasing Re. The pressure coefficient evaluation showed a big difference between its distribution in the subcritical and critical regime. In the subcritical regime, a significant increase in the minimum value and a shift of the extreme close to the axis of the cylinder is proven. The results of the drag coefficient confirm a significant decrease in the transition from subcritical to critical regime, which is indicated in the cited experiments.

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