Numerical Analyses of Flow in Transitions Using Grid Adaptive Method

In this research the two dimensional depth averaged shallow water equations are solved in transitions using MacCormack and two step Lax-Wendroff schemes over a fixed grid. In order to increase the accuracy of the results in the MacCormack scheme, the fixed grid is adjusted using a grid speed technique in each time step. This is a grid adaptive method in which the nodes come close to each other at the places where the flow characteristics (depth and velocity) vary intensely. In this article a new technique is proposed to prevent excessive concentration of the nodes. Using this technique the code run time is reduced considerably. In order to evaluate the accuracy of the results some laboratory tests were performed in a contraction transition. It is observed that the MacCormack scheme with the new grid adaptive technique is more compatible with the experimental results.