Dependence of hydrodynamic forces acting on oscillating thin plates on the shape of edges in the range of large oscillation amplitudes

Abstract

In this work, numerical simulation of the viscous flow past harmonically oscillating thin plates with different shapes of edges is carried out in the Reynolds number range 10 <Re <600. To describe the motion of a fluid, a complete nonstationary system of Navier-Stokes equations is solved. The problem is considered in a plane formulation. The numerical model is implemented on the basis of the open-source OpenFOAM package. The effect of the shape of edges on the hydrodynamic drag in regimes with intense vortex formation is considered. The structure of the flow and the pressure distribution over the plate surface are analyzed, the drag coefficient for different oscillation amplitudes is calculated. The results of the study show that the change of the shape of edges leads to the shift the flow separation points. This has noticeable effect on the pressure distribution on the plate surface. For truncated plates, the difference between the pressure distribution on the right and left sides of the plate in the vicinity of the edges is less than for the rectangular plate. This leads to a decrease the aerodynamic drag of the truncated plate. In the considered range of parameters the values of the drag coefficient for a rectangular plate lie (on the average) 14% higher. The obtained results well explain the large spread of data between the earlier experimental and numerical studies, since in almost all numerical studies the cross section of the plate is assumed rectangular. .At the same time, samples, which are usually used in experiments, have truncated (triangular) edges. The corresponding data for each of these types of plates are in good agreement with the results obtained in this study.

Keywords

• вязкая жидкость
• тонкие пластины
• гармонические осцилляции
• коэффициент гидродинамического сопротивления
• форма торцов, численное моделирование