Investigation of mesh independence in numerical modeling of sharp-crested weirs at different heights

Abstract

Mesh independence is a term used in numerical analysis and simulation to refer to a situation where the numerical solution of a problem is insensitive to changes in the size or density of the computational mesh used to discretize the problem domain. In other words, a numerical solution is said to be mesh independent if it remains stable and accurate even when the mesh is refined. This is important because the accuracy and stability of numerical simulations depend on the quality of the mesh used to discretize the problem domain. The shape, size and number of meshes used while performing numerical modeling in accordance with flow physics in the solution of hydraulic problems significantly affect the result. In this study, a total of 12 experiments were carried out for 4 different discharge values (Q=5 L/s, 10 L/s,15 L/s and 20 L/s) for sharp-crested weirs with three different weir heights (P=20 cm, 30 cm and 40 cm). Numerical models of each experimental setup with four different mesh sizes (m=1.25 mm, 2.50 mm, 5.00 mm and 10.00 mm) were created with the ANSYS-Fluent program. Numerical analyzes were performed using the grid resolution method to obtain a mesh size-independent result where the mesh size would not affect the results after the specified error rate.