NUMERICAL SIMULATION OF FLOW BELOW HYDRAULIC STRUCTURES

Abstract

For a safe design of a hydraulic structure, an estimation of uplift pressure and exit gradient is of vital importance. The prevalent methods based on Khosla's theory or Electrical analogue investigations for the estimation of above parameters have a number of limitations and are based on many assumptions which may not always hold. Hence, a numerical model is developed to facilitate a more rational estimation of uplift pressure, exit gradient and seepage discharge for a given design eliminating the major assumptions. The model is based upon a numerical solution of the differential equation governing two dimensional transient saturated flow in a hetrogeneous porous medium. The numerical solution is obtained by the finite differences. The model has been validated by comparing its results with Khosla's curves and the results of Electrical analogy investigations under the ideal conditions. The impact of basic assumptions of Khosla's theory are examined using the model,