Open AccessA Two-Dimensional Computational Study of a Single Right Trapezoidal Cylinder Subjected to Unsteady Laminar Flow Regime at Low Reynolds Number
Author(s) -
Sodsai Lamtharn,
Monsak Pimsarn
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/886/1/012022
Subject(s) - vortex shedding , reynolds number , laminar flow , mechanics , strouhal number , cylinder , potential flow around a circular cylinder , piping , physics , geometry , mathematics , turbulence , thermodynamics
A right trapezoidal cross-section cylinder is used as guided bars for a barred tee in the long pipeline and piping system to protect the moving of pigs across the branched pipe. The cylinder must have the integrity to withstand to fluid flows-induced vibration which concerns the synchronization between vortex shedding frequency of fluid flows with a natural frequency of the cylinder. Therefore, this article aims to numerically investigate the vortex shedding frequency responses which are in terms of Strouhal number, flow force coefficients and in order to provide additional data for use in the absence of more applicable data for engineering design of the single right trapezoidal cylinder in structural integrity point of view. In this study, the simulation of the single right trapezoidal cylinder immersed in the uniform oncoming laminar flow regime with low Reynolds number; Re = 100, was performed. There are various sharpening angles in this study; defined as angle which is measured from virtual line parallel with height base side to slant side or (90°- acute angle° ) of the cylinder, in the range of 0°, 15°, 22.5°, 40° and 60°, accompanying with the cylinder side ratio ( B / A ) which is the ratio of the longest base side-to-height base side, in the range of 1, 2, 3, 4, 5, 6 and 7. In the simulation, the Direct Numerical Simulation (DNS) with a finite volume method, an incompressible flow and constant fluid properties were employed. The computational results were validated against the published data. The effect of the sharpening angle and side ratio on the response of the single right trapezoidal cylinder were presented and discussed. The Strouhal number and flow force coefficients at fully ten cycle of saturated flow have been calculated. The simulated results show that increasing of sharpening angle, the Strouhal number slightly increases whilst the root mean square lift coefficients significantly increases. Additionally, as the side ratio increases, the Strouhal number and the root mean square lift coefficients decreases.