The Effects of Grid Shape on Numerical Results: a Case Study of Fluid Flow in Cylindrical Pipe Yusron Feriadi(a)(b*), Umar Fauzi(a), M Rizqie Arbie(a), Fariduzzaman(c)
a) Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology
b) Research Center for Hydrodynamics Technology, National Research and Innovation Agency (BRIN)
*yusr004[at]brin.go.id
c) Laboratory for Aerodynamics, Aeroelastics and Aeroacoustics, National Research and Innovation Agency (BRIN)
Abstract
Generating high-quality grids is a challenge in computational simulations because the accuracy of the grid greatly affects the quality of the numerical simulation results. In this study, several grid shapes and sizes were tested to analyze this effect on the simulation. In general, structured and unstructured grids are used in this study, which consist of hexagonal and prism grids. Grid variation is applied to the case of poiseuille flow with a Reynolds number of 250. The pipe used has a length of 30 cm and a diameter of 1 mm, and a pressure difference of 2.4 pascal is applied between the two boundaries so that water flows from the inlet to the outlet. We adopted the finite volume method to solve the Navier-Stokes equation via the PIMPLE algorithm, which is a combination of the PISO algorithm (implicit pressure with splitting of operator) and SIMPLE (semi-implicit method for pressure-linked equations) The simulation results are then compared with the exact results, where the velocity profile around the outlet and the maximum speed are evaluated. To assess the quality of the simulation results, we used two equations, namely L2 norm and absolute error. The simulation shows that a larger number of grids increases the quality of the simulation results and hexagonal grid performance is better than prism one.
