Fluid Mechanics

The Unsteady Flow of Fluid in a Revolving Cylinder

The paper investigates the unsteady and nonsensical flow of fluid in a revolving cylinder using the Reynolds number of 150. The research is conducted at unique and alternate vortex periods. Fluid flow is studied using continuity equations and the Navier-Stokes equation using the finite volume technique. The fluid flow parameters in the continuity equation include lift and drag coefficients, pressure contours, velocity contours, vorticity contours, Strouhal number, and pressure coefficient. In this study, all of the above measurements were calculated and compared to other experimental and numerical findings, which show strong agreement. The results of the study show that the fluid flow in the entrance cylindrical boundary is unsteady in spite of the steady flow. The results have also shown an alteration in the fluid flow and this has created a minimum value on the symmetry line in the calculation domain.

Keywords

Circular Cylinder- Strouhal number, unsteady flow, Drag and Lift coefficient and Finite Volume Method.

Introduction

Many complex computations relating to the aerodynamics are categorized under incompressible fluid flow and in most cases, the flow is usually unsteady; most of the flow conditions like the Reynolds number are considered. In this study, the analysis of the above types of the fluid flow system is essential. The flow systems around objects like square and circular cylinders are mostly applied in the field of engineering. Chimneys, tall buildings, heat exchange tubes, and cooling towers are examples of the engineering applications of fluid mechanics. A lot of research has been done on the flow systems around the cylinders and a variety of geometrics and computations have been established to enhance the studies in fluid mechanics. The study perspective of the fluid flow is coupled to the force coefficient, pressure distribution, flow patterns, Strouhal number, and vortex shedding. Most of the research on fluid flow around the cylinders has been done through wind tunnel experiments or numerical methods, and only the limit numerics of these studies carried out from the dimension of the actual scales. The fluid flow in the circular cylinder constitutes the major parts of the recent researches in the field of fluid mechanics because of its applicability in engineering. The studies also involve geometric simplicity. The fluid flow quantities on the cylindrical surface absolutely change with the increase in the Reynolds number. For instance, when the vortex measurement arises at the back of the circular cylindrical tube, the frictional drag inside the circular cylinder amplifies and the body experiences an intermittent force in the regular direction of the main flow stream. The distribution in pressure within the circular cylinder, the coefficient factor of drag and lift as well as the Strouhal number (Re = 200) have been investigated in the hydrodynamics characteristics of flow in the circular cylinder. According to Rajani (2009), the pressure-based finite volume method is applied in the accurate calculation of the incompressible fluid flow by the use of the second-order convective flux scheme. The resulting computational evidence is compared to the measurement of data obtained from the mean surface pressure, the length and size of the recirculation wake in the steady flow process and for the Strouhal frequency in the vortex shedding as well as the RMS and mean amplitude of the alternating aerodynamics coefficients in the unsteady intermittent flow process. The three-dimensional flow system in the cylinder is also captured by the current prediction process.

Reference

Rajani, B. N., Kandasamy, A., & Majumdar, S. (2009). Numerical simulation of laminar flow past a circular cylinder. Applied Mathematical Modelling, 33(3), 1228-1247.